TY - JOUR A1 - Lörchner, Dominique A1 - Kraus, Werner A1 - Köppen, Robert T1 - Photodegradation of the novel brominated flame retardant 2,4,6-Tris-(2,4,6-tribromophenoxy)-1,3,5-triazine in solvent system: Kinetics, photolysis products and pathway. N2 - In this study the direct and indirect photolysis of the novel brominated flame retardant 2,4,6-Tris-(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ) in an organic solvent mixture (60:30:10, ACN:MeOH:THF) under UV-(C) and simulated sunlight irradiation was investigated, and the formed photo-transformation products were identified for the first time. TTBP-TAZ was almost completely degraded within 10 min under UV-(C) irradiation. Due to the fast degradation no specific kinetic order could be observed. In comparison, the reaction under simulated sunlight irradiation was much slower and thus, the kinetic first-order could be determined. The observed photolysis rate constant k as well as the half-life time t1/2 were estimated to be k = (0.0163 ± 0.0002) h-1 and t1/2 = 42.3 h, respectively. The addition of 2-propanol and hydrogen peroxide to investigate the influence of indirect photolysis under UV-(C) irradiation causes no influence on the degradation of TTBP-TAZ. Nevertheless, the removal of TTBP-TAZ under UV-(C) and simulated sunlight without additional chemicals (except solvent) indicates that the direct photolysis plays a significant role in the degradation mechanism of TTBP-TAZ. In both irradiation experiments, TTBP-TAZ was quantitatively degraded that involve the formation of previously unknown PTPs. Overall, two main PTPs were determined when irradiated with UV-(C) and eight sequential debromination products were observed when irradiated by simulated sunlight. These were determined by HPLC-DAD and - MS/(MS), respectively. Based on the chosen experimental conditions the consecutive debromination as well as photo-Fries rearrangement was confirmed as the main degradation pathway by high resolution mass spectrometry and X-ray diffraction. KW - XRD KW - Direct/indirect photolysis KW - HRMS KW - Photo-transformation products KW - TTBP-TAZ PY - 2019 DO - https://doi.org/10.1016/j.chemosphere.2019.04.184 SN - 0045-6535 SN - 1879-1298 VL - 229 SP - 77 EP - 85 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-48066 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Surov, Artem O. A1 - Vasilev, Nikita A. A1 - Churakov, Andrei V. A1 - Stroh, Julia A1 - Emmerling, Franziska A1 - Perlovich, German L. T1 - Solid Forms of Ciprofloxacin Salicylate: Polymorphism, Formation Pathways, and Thermodynamic Stability N2 - The crystallization of ciprofloxacin - an antibacterial fluoroquinolone compound - with salicylic acid resulted in the isolation of five distinct solid forms of the drug, namely, an anhydrous salt, two polymorphic forms of the salt monohydrate, methanol and acetonitrile solvates, and the salt-cocrystal hydrate. The salicylate salts were investigated by different analytical techniques ranging from powder and single crystal X-ray diffractometry, differential scanning calorimetry, thermogravimetric analysis, variable temperature powder X-ray diffraction, dynamic vapor sorption analysis, dissolution, and solubility investigations. Real-time in situ Raman spectroscopy was used to investigate the mechanochemical formation pathways of the different solid polymorphs of ciprofloxacin salicylate. The mechanism of the phase transformation between the crystalline forms was evaluated under mechanochemical conditions. It was found that the formation pathway and kinetics of the grinding process depend on the form of the starting material and reaction conditions. The analysis of the solid-state thermal evolution of the hydrated salts revealed the two-step mechanism of dehydration process, which proceeds through a formation of the distinct intermediate crystalline products. KW - Cocrystal KW - Polymorphism KW - Ciprofloxacin KW - XRD KW - DSC PY - 2019 DO - https://doi.org/10.1021/acs.cgd.9b00185 SN - 1528-7483 VL - 19 IS - 5 SP - 2979 EP - 2990 PB - American Chemical Society AN - OPUS4-47903 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kulow, Anicó A1 - Witte, S. A1 - Beyer, S. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Riesemeier, H. A1 - Streli, C. T1 - A new experimental setup for time- and laterally-resolved X-ray absorption fine structure spectroscopy in a 'single shot' N2 - In this work, a new setup for dispersive XAFS measurements is presented. This reproducible and scanningfree setup yields both time- and laterally-resolved XAFS experiments in a ‘single-shot’. It allows a straightforward adjustment for probing different elements covering many relevant applications in materials science. An incoming energetic broadband beam is diffracted by a Si (111) crystal after passing through the sample and collected by an area sensitive detector. Depending on the energy range of the incoming beam, XANES and/or EXAFS spectra can be recorded with a time resolution down to 1 s. The feasibility of this setup was demonstrated at the BAMline at BESSY II (Berlin, Germany) with reference Fe and Cu foils and the results are hereby presented and discussed. Additionally, an application where time resolution on the second scale is required is briefly evaluated. The presented example concerns studying early stages of zinc(II)2-methylimidazolate (ZIF-8) crystallization. This is particularly important for biomedical applications. KW - X-ray spectroscopy KW - X-ray absorption fine structure KW - Time-resolved KW - Laterally-resolved KW - Experimental setup PY - 2019 DO - https://doi.org/10.1039/c8ja00313k SN - 0267-9477 SN - 1364-5544 VL - 34 IS - 1 SP - 239 EP - 246 PB - Royal Society of Chemistry CY - London AN - OPUS4-47207 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Manso, M. A1 - Pessanha, S. A1 - Guerra, M. A1 - Reinholz, Uwe A1 - Afonso, C. A1 - Radtke, Martin A1 - Lourenco, H. A1 - Carvalho, M. L. A1 - de Oliveira Guilherme Buzanich, Ana T1 - Assessment of Toxic Metals and Hazardous Substances in Tattoo Inks Using Sy-XRF, AAS, and Raman Spectroscopy N2 - Synchrotron radiation X-ray fluorescence spectroscopy, in conjunction with atomic absorption and Raman spectroscopy, was used to analyze a set of top brand tattoo inks to investigate the presence of toxic elements and hazardous substances. The Cr, Cu, and Pb contents were found to be above the maximum allowed levels established by the Council of Europe through the resolution ResAP(2008)1 on requirements and criteria for the safety of tattoos and permanent makeup. Raman analysis has revealed the presence of a set of prohibited substances mentioned in ResAP(2008)1, among which are the pigments Blue 15, Green 7, and Violet 23. Other pigments that were identified in white, black, red, and yellow inks are the Pigment White 6, Carbon Black, Pigment Red 8, and a diazo yellow, respectively. The present results show the importance of regulating tattoo ink composition. KW - Synchrotron KW - Tattoo inks KW - XRF KW - Toxic metals KW - Hazardous substances PY - 2019 DO - https://doi.org/10.1007/s12011-018-1406-y VL - 187 IS - 2 SP - 596 EP - 601 PB - Springer AN - OPUS4-47369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weber, Kathrin A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Stephan-Scherb, Christiane T1 - A µ‐XANES study of the combined oxidation/sulfidation of Fe–Cr model alloys N2 - The precise analysis of cation diffusion profiles through corrosion scales is an important aspect to evaluate corrosion phenomena under multicomponent chemical load, as during high‐temperature corrosion under deposits and salts. The present study shows a comprehensive analysis of cation diffusion profiles by electron microprobe analysis and microbeam X‐ray absorption near edge structure (µ‐XANES) spectroscopy in mixed oxide/sulfide scales grown on Fe–Cr model alloys after exposing them to 0.5% SO2. The results presented here correspond to depth‐dependent phase identification of oxides and sulfides in the corrosion scales by µ‐XANES and the description of oxidation‐state‐dependent diffusion profiles. Scales grown on low‐ and high‐alloyed materials show both a well‐pronounced diffusion profile with a high concentration of Fe3+ at the gas and a high concentration of Fe2+ at the alloy interface. The distribution of the cations within a close‐packed oxide lattice is strongly influencing the lattice diffusion phenomena due to their different oxidation states and therefore different crystal‐field preference energies. This issue is discussed based on the results obtained by µ‐XANES analysis. KW - X-ray absorption spectroscopy KW - Oxidation KW - Sulfidation PY - 2019 DO - https://doi.org/10.1002/maco.201810644 VL - 70 IS - 8 SP - 1360 EP - 1370 PB - Wiley VCH-Verlag AN - OPUS4-47934 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bierstedt, Andreas A1 - You, Yi A1 - van Wasen, Sebastian A1 - Bosc-Bierne, Gaby A1 - Weller, Michael G. A1 - Riedel, Jens T1 - Laser-Induced Microplasma as an Ambient Ionization Approach for the Mass-Spectrometric Analysis of Liquid Samples N2 - An airborne high repetition rate laser-induced plasma was applied as a versatile ambient ionization source for mass-spectrometric determinations of polar and nonpolar analytes in solution. The laser plasma was sustained between a home-built pneumatic nebulizer and the inlet capillary of an Orbitrap mass spectrometer. To maintain stable conditions in the droplet-rich spray environment, the plasma was directly fed by the fundamental output (λ = 1064 nm) of a current state-of-the-art diode-pumped solid-state laser. Ionization by the laser-driven plasma resulted in signals of intact analyte ions of several chemical categories. The analyte ions were found to be fully desolvated since no further increase in ion signal was observed upon heating of the inlet capillary. Due to the electroneutrality of the plasma, both positive and negative analyte ions could be formed simultaneously without altering the operational parameters of the ion source. While, typically, polar analytes with pronounced gas phase basicities worked best, nonpolar and amphoteric compounds were also detected. The latter were detected with lower ion signals and were prone to a certain degree of fragmentation induced during the ionization process. All the described attests the laser-induced microplasma by a good performance in terms of stability, robustness, sensitivity, and general applicability as a self-contained ion source for the liquid sample introduction. KW - Laser KW - Laser-induced plasma KW - Ambient ionization KW - Mass Spectrometry PY - 2019 DO - https://doi.org/10.1021/acs.analchem.9b00329 SN - 0003-2700 VL - 91 IS - 9 SP - 5922 EP - 5928 PB - American Chemical Society CY - Washington, DC, USA AN - OPUS4-47939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Trimpin, S. A1 - Inutan, E. A1 - Karki, S. A1 - Elia, E. A1 - Zhang, W. A1 - Weidner, Steffen A1 - Marshall, D. A1 - Hoang, K. A1 - Lee, C. A1 - Davis, E. A1 - Smith, V. A1 - Meher, A. A1 - Cornejo, M. A1 - Auner, G. A1 - McEwen, C. T1 - Fundamental studies of new ionization technologies and insights from IMS-MS N2 - Exceptional ion mobility spectrometry mass spectrometry (IMS-MS) developments by von Helden, Jarrold, and Clemmer provided technology that gives a view of chemical/biological compositions previously not achievable. The ionization method of choice used with IMS-MS has been electrospray ionization (ESI). In this Special issue contribution, we focus on fundamentals of heretofore unprecedented means for transferring volatile and nonvolatile compounds into gas-phase ions singly and multiply charged. These newer ionization processes frequently lead to different selectivity relative to ESI and, together with IMS-MS, may provide a more comprehensive view of chemical compositions directly from their original Environment such as surfaces, e.g., tissue. Similarities of results using solvent- and matrix-assisted ionization are highlighted, as are differences between ESI and the inlet ionization methods, especially with mixtures such as bacterial extracts. Selectivity using different matrices is discussed, as are results which add to our fundamental knowledge of inlet ionization as well as pose additional avenues for inquiry. IMS-MS provides an opportunity for comparison studies relative to ESI and will prove valuable using the new ionization technologies for direct analyses. Our hypothesis is that some ESI-IMS-MS applications will be replaced by the new ionization processes and by understanding mechanistic aspects to aid enhanced source and method developments this will be hastened. KW - Inlet ionization KW - Vacuum ionization KW - Matrices KW - Fundamentals KW - Ion mobility PY - 2019 DO - https://doi.org/10.1007/s13361-019-02194-7 SN - 1044-0305 SN - 1879-1123 VL - 30 IS - 6 SP - 1133 EP - 1147 PB - Springer AN - OPUS4-48011 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Al-Terkawi, Abdal-Azim A1 - Prinz, Carsten A1 - Scholz, Gudrun A1 - Kemnitz, Erhard A1 - Emmerling, Franziska T1 - Ca-, Sr-, and Ba-Coordination polymers based on anthranilic acid via mechanochemistry N2 - Ca-, Sr-, and Ba-Based coordination polymers (CPs) were prepared mechanochemically by milling metal-hydroxide samples with anthranilic acid (oABAH). {[Ca(oABA)2(H2O)3]}n consists of one-dimensional polymeric chains that are further connected by a hydrogen-bonding network. {[Sr(oABA)2(H2O)2]·H2O}n is a one-dimensional CP in which water molecules bridge Sr2+ ions and increase the dimensionality by building an extended network. {[Ba(oABA)2(H2O)]}n crystallizes as a two-dimensional CP comprising one bridging water molecule. The cation radii influence the inorganic connectivity and dimensionality of the resulting crystal structures. The crystal structures were refined from powder X-ray diffraction data using the Rietveld method. The local coordination environments were studied via extended X-ray absorption fine structure (EXAFS) measurements. The compounds were further characterized using comprehensive analytical methods such as elemental analysis, thermal analysis, MAS NMR, imaging, and dynamic vapor sorption (DVS) measurements. Compounds 1, 2, and 3 exhibit small surface areas which decrease further after thermal annealing experiments. All compounds exhibit a phase transformation upon heating, which is only reversible in 3. KW - Mechanochemistry KW - XRD PY - 2019 DO - https://doi.org/10.1039/c9dt00991d SN - 1477-9226 SN - 1477-9234 VL - 48 IS - 19 SP - 6513 EP - 6521 PB - Royal Society of Chemistry AN - OPUS4-48014 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kulow, Anicó T1 - X-ray imaging with coded apertures N2 - Coded aperture imaging systems are in use in astrophysics since the 1960's. We want to adapt this technique for full field x-ray fluorescence imaging in combination with a color-x-ray-camera. T2 - Seminar des Atominstituts der TU Wien CY - Vienna, Austria DA - 14.05.2019 KW - Reconstruction KW - X-ray spectroscopy KW - X-ray fluorescence KW - Spectroscopy KW - Imaging KW - Coded apertures PY - 2019 AN - OPUS4-47997 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kulla, Hannes A1 - Michalchuk, Adam A1 - Emmerling, Franziska T1 - Manipulating the dynamics of mechanochemical ternary cocrystal formation N2 - The mechanism of ternary cocrystal formation, and the potential role of intermediate binary phases, has been debated for some time. We report here the first in situ real-time monitoring of two prototypic ternary cocrystals. Our results suggest that the question is more complicated than previously considered. The mechanism of mechanochemical ternary cocrystal formation depends on the milling conditions, here the milling frequency and addition of liquid. Binary phases can form under certain conditions, but do not act as intermediates in the formation of the ternary cocrystals. Rather, binary phases are competitive with the ternary phase, and their formation appears to compete with that of the ternary components. The presence of binary phases leads to an increase in the overall reaction time. The results reported here offer the first insights into the true complexities of mechanochemical multi-component synthesis of higher order multi-component crystals and demonstrate a new understanding of the influence of milling condition for the study of mechanisms and kinetics. KW - Mechanochemistry KW - In situ KW - Cocrystal PY - 2019 UR - https://pubs.rsc.org/en/content/articlepdf/2019/cc/c9cc03034d DO - https://doi.org/10.1039/c9cc03034d SN - 1364-548X VL - 55 IS - 66 SP - 9793 EP - 9796 PB - RSC AN - OPUS4-48613 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - You, Yi A1 - Bierstedt, Andreas A1 - Riedel, Jens T1 - Spatial, temporal, and spectral characterization and kinetic investigations of a high repetition-rate laser-induced micro-plasma in air N2 - Advances in laser-induced plasmas have enabled various rapid and simple analytical applications. Especially, their uses in the analyses of condensed-phase samples have drawn significant attention in the past few decades. Depending on the laser energy per pulse, various analytical goals can be achieved. Laser-induced airborne plasmas allow direct analysis of species in ambient air. Importantly, all of these applications are based on a fundamental understanding of the laser–medium interaction. Recent developments of diode-pumped solid-state lasers offer an alternative to conventional powerful, yet bulky lasers, which can specifically operate at high Repetition rates. Although these lasers deliver much lower power per pulse (mJ compared to mJ), the outstanding repetition rates offer significant improvement to meet statistical needs in some cases. In the present work, a mJ-laserinduced airborne plasma was characterized through optical emission analysis. By using a ns-timegated image detector coupled with specific bandpass filters, spatially, temporally, and spectrally resolved plasma images were recorded. Compared to conventional mJ-laser-induced plasmas, the one induced by mJ-lasers demonstrated unique features during its evolution. Specifically, measurements of the distribution of ionic and atomic species revealed distinctive energy/matter transfer processes during early ignition of the plasma. Meanwhile, dynamic investigations suggested subsequent matter transport in the later stage. KW - Laser-induced plasma KW - Plasma KW - DPSS-laser PY - 2019 UR - https://pubs.rsc.org/en/content/articlehtml/2019/ja/c9ja00163h DO - https://doi.org/10.1039/C9JA00163H SN - 0267-9477 VL - 34 IS - 8 SP - 1618 EP - 1629 PB - Royal Society of Chemistry CY - London AN - OPUS4-48622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Emmerling, Franziska T1 - Foschung an der BAM - Von Termiten bis zum 3D Druck in der Schwerelosigkeit N2 - Eine Übersicht über die Forschung an der BAM mit Schwerpunkt auf dem Fachbereich Strukturanalytik T2 - Naturwissenschaftstag in Senftenberg CY - Senftenberg, Germany DA - 14.06.19 KW - Mechanochemie KW - XRD PY - 2019 AN - OPUS4-48393 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Emmerling, Franziska T1 - How to write your thesis N2 - Useful tips & tricks to overcome procrastination and get you PhD thesis written. T2 - 13. Interdisziplinäres Doktorandenseminar CY - Berlin, Germany DA - 19.03.2019 KW - Outreach KW - Pomodore KW - Deep work PY - 2019 AN - OPUS4-48097 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Emmerling, Franziska T1 - New insights in cocrystal formations: in situ investigations of mechanochemical syntheses N2 - Mechanochemistry is increasingly used for synthesizing soft matter materials including metal organic compounds and cocrystals. The ever-increasing interest in this method is contrasted by a limited mechanistic understanding of the mechanochemical reactivity and selectivity. Time-resolved in situ investigations of milling reactions provide direct insights in the underlying mechanisms. We introduced a setup enabling in situ investigation of mechanochemical reactions using synchrotron XRD combined with Raman spectroscopy. The specific combination allows to study milling processes comprehensively on the level of the molecular and crystalline structure and thus obtaining reliable data for mechanistic studies. We discuss our recent results investigating the formation of (polymorphic) cocrystals. First investigations of a mechanochemical synthesis under controlled temperature which allow determining the activation barrier are presented.6 Furthermore, X-ray diffraction and in situ Raman spectroscopy coupled with thermography revealed a low temperature increase during milling reactions due to the mechanical impact and clear temperature increases as a result of the reaction heat. Our results indicate that in situ investigation of milling reactions offer a new approach to tune and optimize mechanochemically synthesized compounds. T2 - CSEC Seminar University of Edinburgh CY - Edinburgh, Scotland DA - 16.05.2019 KW - Mechanochemistry KW - Acoustic levitation KW - In situ PY - 2019 AN - OPUS4-48098 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wahl, S. A1 - El-Refaei, S. M. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Amsalem, P. A1 - Lee, K.-S. A1 - Koch, N. A1 - Doublet, M.-L. A1 - Pinna, N. T1 - Zn0.35Co0.65O – A Stable and highly active oxygen evolution catalyst formed by zinc leaching and tetrahedral coordinated cobalt in wurtzite structure N2 - To arrive to sustainable hydrogen-based energy solutions, the understanding of water-splitting catalysts plays the most crucial role. Herein, state-of-the-art hypotheses are combined on electrocatalytic active metal sites toward the oxygen evolution reaction (OER) to develop a highly efficient catalyst based on Earth-abundant cobalt and zinc oxides. The precursor catalyst Zn0.35Co0.65O is synthesized via a fast microwaveassisted approach at low temperatures. Subsequently, it transforms in situ from the wurtzite structure to the layered γ-Co(O)OH, while most of its zinc leaches out. This material shows outstanding catalytic Performance and stability toward the OER in 1 m KOH (overpotential at 10 mA cm−2 ηinitial = 306 mV, η98 h = 318 mV). By comparing the electrochemical results and ex situ analyses to today’s literature, clear structureactivity correlations are able to be identified. The findings suggest that coordinately unsaturated cobalt octahedra on the surface are indeed the active centers for the OER. KW - Oxygen Evolution Catalyst KW - XAFS KW - Oxygen evolution reaction (OER) KW - Cobalt and zinc oxides PY - 2019 DO - https://doi.org/10.1002/aenm.201900328 SN - 1614-6832 SN - 1614-6840 VL - 9 IS - 20 SP - 1900328,1 EP - 10 PB - WILEY-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-48200 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Characterization of co (polyamide)s N2 - Characterization problems of technically relevant copolyamides applying size exclusion chromatography, interaction chromatography and their combination with MALDI-TOF-MS will be discussed. T2 - 23. Kolloquium Massenspektrometrie und synthetische Polymere CY - Berlin, Germany DA - 14.05.2019 KW - LCCC KW - Mass spectrometry of polymers KW - SEC KW - LC / MALDI-TOF-MS coupling PY - 2019 AN - OPUS4-48221 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Shedding Light into Polymer Microstructure N2 - It is a well-known story that copolymers beside their molar mass distribution (MMD) can exhibit a functionality type distribution (FTD), a copolymer composition distribution (CCD), a monomer sequence distribution (MSD) and additionally different topologies within one sample. Nowadays a wide range of different analytical separation techniques and multi-detection possibilities are available. The challenge consists in a clever combination of these techniques coordinated with the heterogeneity to be investigated. A number of applications will be presented from e.g. topology elucidation of branched EO-PO “academic” copolymers to copolymer composition of partially broadly distributed progressively tailored “industrial relevant” copolymers consisting of e.g. polyamides, polycarbonates and polysiloxanes. Multidimensional separation techniques will be demonstrated with focus on mass spectrometric detection techniques (ESI-/MALDI-TOF-MS) coupled online or semi-online to prior separation. T2 - FAST 2019, COAST Community of Innovation CY - Veldhoven, The Netherlands DA - 21.05.2019 KW - LCCC KW - Mass spectrometry of polymers KW - SEC KW - LC x MALDI/ESI-TOF-MS coupling PY - 2019 AN - OPUS4-48222 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Coupling of chromatographic and spectrometric techniques for polymer characterization N2 - Presentation of coupling of polymer chromatography and polymer mass spectrometry based on different examples. T2 - Kolloquium CY - Universität für Bodenkultur, Wien, Austria DA - 14.06.2019 KW - LCCC KW - Mass spectrometry of polymers KW - LC x MALDI/ESI-TOF-MS KW - Liquid chromatography of polymers PY - 2019 AN - OPUS4-48223 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Haferkamp, Sebastian A1 - Paul, Andrea A1 - Michalchuk, Adam A1 - Emmerling, Franziska T1 - Unexpected polymorphism during a catalyzed mechanochemical Knoevenagel condensation N2 - The transformation of a base-catalyzed, mechano-assisted Knoevenagel condensation of mono-fluorinated benzaldehyde derivatives (p-, m-, o-benzaldehyde) with malonodinitrile was investigated in situ and in real time. Upon milling, the para-substituted product was found to crystallize initially into two different polymorphic forms, depending on the quantity of catalyst used. For low catalyst concentrations, a mechanically metastable phase (monoclinic) was initially formed, converting to the mechanically stable phase (triclinic) upon further grinding. Instead, higher catalyst concentrations crystallize directly as the triclinic product. Inclusion of catalyst in the final product, as evidenced by mass spectrometric analysis, suggests this complex polymorphic pathway may be due to seeding effects. Multivariate analysis for the in situ Raman spectra supports this complex formation pathway, and offers a new approach to monitoring multi-phase reactions during ball milling. KW - Ball milling KW - C-C coupling KW - In situ KW - Mechanochemistry KW - Multivariate data analysis PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-481872 DO - https://doi.org/10.3762/bjoc.15.110 SN - 1860-5397 VL - 15 SP - 1141 EP - 1148 PB - Beilstein Insitut CY - Frankfurt am Main AN - OPUS4-48187 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Linberg, Kevin A1 - Ali, Naveed Zafar A1 - Etter, M. A1 - Michalchuk, Adam A1 - Rademann, K. A1 - Emmerling, Franziska T1 - A Comparative Study of the Ionic Cocrystals NaX (α-d-Glucose)2 (X = Cl, Br, I) N2 - The mechanochemical formation of the ionic cocrystals of glucose (Glc) and sodium salts Glc2NaCl·H2O (1) and Glc2NaX (X = Br (2), I (3)) is presented. Products are formed by co-milling Glc with three sodium salts (NaCl, NaBr, NaI). The ionic cocrystals were obtained under both neat grinding and liquid-assisted grinding conditions, the later found to accelerate the reaction kinetics. The crystal structures of the ionic cocrystals (2) and (3) were solved from powder X-ray diffraction data. The structure solution contrasts with the structure of Glc2NaCl·H2O (1) where the electron density at three halide crystallographic sites is modeled as of being the intermediate between water molecule and a chloride ion. The reaction pathways of the three ionic cocrystals were investigated in real time using our tandem approach comprising a combination of in situ synchrotron powder X-ray diffraction and Raman spectroscopy. The results indicate the rapid formation of each cocrystal directly from their respective starting materials without any intermediate moiety formation. The products were further characterized by DTA-TG and elemental analysis. KW - In situ KW - Co-crystal KW - Mechanochemistry KW - Glucose PY - 2019 DO - https://doi.org/10.1021/acs.cgd.8b01929 VL - 19 IS - 8 SP - 4293 EP - 4299 PB - ACS Publications AN - OPUS4-48781 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ali, Naveed Zafar A1 - Campbell, B. J. A1 - Jansen, M. T1 - Topotactic, pressure-driven, diffusion-less phasetransition of layered CsCoO2to a stuffedcristobalite-type configuration N2 - CsCoO2, featuring a two-dimensional layered architecture of edge- and vertex-linked CoO4tetrahedra, is subjected to a temperature-driven reversible second-order phase transformation at 100 K, which corresponds to a structuralrelaxation with concurrent tilting and breathing modes of edge-sharing CoO4tetrahedra. In the present investigation, it was found that pressure induces a phase transition, which encompasses a dramatic change in the connectivity ofthe tetrahedra. At 923 K and 2 GPa, beta-CsCoO2 undergoes a first-order phasetransition to a new quenchable high-pressure polymorph,alpha-CsCoO2. It is built up of a three-dimensional cristobalite-type network of vertex-sharing CoO4 tetrahedra. According to a Rietveld refinement of high-resolution powderdiffraction data, the new high-pressure polymorph gamma-CsCoO2 crystallizes in the tetragonal space groupI41/amd:2 (Z= 4) with the lattice constants a= 5.8711 (1) and c= 8.3214 (2) A, corresponding to a shrinkage in volume by 5.7% compared with the ambient-temperature and atmospheric pressure-CsCoO2polymorph.The pressure-induced transition (beta>gamma) is reversible;-CsCoO2 stays metastable under ambient conditions, but transforms back to the-CsCoO2structure upon heating to 573 K. The transformation pathway revealed isremarkable in that it is topotactic, as is demonstrated through a clean displacive transformation track between the two phases that employs the symmetry oftheir common subgroupPb21a(alternative setting of space group No. 29 that matches the conventional-phase cell). KW - Structures under extreme conditions KW - Topotactic phase transitions KW - Transformation pathways KW - Oxocobaltates KW - Cristobalite frameworks PY - 2019 DO - https://doi.org/10.1107/S2052520619008436 SN - 2052-5206 VL - 75 IS - 4 SP - 704 EP - 710 PB - International Union of Crystallography AN - OPUS4-48782 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mutruc, D. A1 - Goulet-Hanssens, A. A1 - Fairmann, S. A1 - Wahl, S. A1 - Zimathies, Annett A1 - Knie, C. A1 - Hecht, S. T1 - Modulating Guest Uptake in Core-Shell MOFs with Visible Light N2 - A two-component core-shell UiO-68 type metal-organic framework (MOF) with a nonfunctionalized interior for efficient guest uptake and storage and a thin light-responsive outer shell was prepared by initial solvothermal MOF synthesis followed by solvent-assisted linker exchange. The bulky shell linker features two tetra-ortho-fluorinated azobenzene moieties to exploit their advantageous photoisomerization properties. The obtained perfect octahedral MOF single crystals can be switched repeatedly and with an unprecedented efficiency between E- and Z-rich states using visible light only. Due to the high photoswitch density per pore of the shell layer, its steric demand and thus molecular uptake (and release) can be conveniently modulated upon green and blue light irradiation. Therefore, the "smart" shell acts as a light-controlled kinetic barrier or "gate" for the diffusion of cargo molecules in and out of the MOF crystals. KW - Visible light KW - Azobenzene KW - Guest uptake/release KW - Metal– organic frameworks KW - Photochromism PY - 2019 DO - https://doi.org/10.1002/anie.201906606 VL - 58 SP - 12862 EP - 12867 PB - WILEY-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-48941 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Moldovan, R.-P. A1 - Wenzel, B. A1 - Teodoro, R. A1 - Neumann, W. A1 - Dukic-Stefanovic, S. A1 - Kraus, Werner A1 - Rong, P. A1 - Deuther-Conrad, W. A1 - Hey-Hawkins, E. A1 - Krügel, U. A1 - Brust, P. T1 - Studies towards the development of a PET radiotracer for imaging of the P2Y1 receptors in the brain: synthesis, 18F-labeling and preliminary biological evaluation N2 - Purine nucleotides such as ATP and ADP are important extracellular signaling molecules in almost all tissues activating various subtypes of purinoreceptors. In the brain, the P2Y1 receptor (P2Y1R) subtype mediates trophic functions like differentiation and proliferation, and modulates fast synaptic transmission, both suggested to be affected in diseases of the central nervous system. Research on P2Y1R is limited because suitable brain-penetrating P2Y1R-selective tracers are not yet available. Here, we describe the first efforts to develop an 18F-labeled PET tracer based on the structure of the highly affine and selective, non-nucleotidic P2Y1R allosteric modulator 1-(2-[2-(tert-butyl)phenoxy]pyridin-3-yl)-3- [4-(trifluoromethoxy)phenyl]urea (7). A small series of fluorinated compounds was developed by systematic modification of the p-(trifluoromethoxy)phenyl, the urea and the 2-pyridyl subunits of the lead compound 7. Additionally, the p-(trifluoromethoxy)phenyl subunit was substituted by carborane, a boron-rich cluster with potential applicability in boron neutron capture therapy (BNCT). By functional assays, the new fluorinated derivative 1-{2-[2-(tert-butyl)phenoxy]pyridin-3-yl}-3-[4-(2-fluoroethyl) phenyl]urea (18) was identified with a high P2Y1R antagonistic potency (IC50 ¼10 nM). Compound [18F] 18 was radiosynthesized by using tetra-n-butyl ammonium [18F]fluoride with high radiochemical purity, radiochemical yield and molar activities. Investigation of brain homogenates using hydrophilic interaction chromatography (HILIC) revealed [18F]fluoride as major radiometabolite. Although [18F]18 showed fast in vivo metabolization, the high potency and unique allosteric binding mode makes this class of compounds interesting for further optimizations and investigation of the theranostic potential as PET tracer and BNCT agent. KW - Purine P2Y1 receptors KW - Positron emission tomography KW - Brain PET tracers KW - Radiometabolites KW - Micellar chromatography KW - Hydrophilic interaction chromatography PY - 2019 DO - https://doi.org/10.1016/j.ejmech.2019.01.006 SN - 0223-5234 VL - 165 SP - 142 EP - 159 PB - Elsevier CY - Amsterdam AN - OPUS4-47253 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - de Oliveira Guilherme Buzanich, Ana T1 - Career talk & lab tour - Working at BESSY II, a large scale research facility in Adlershof N2 - What exactly does a postdoc do at a research institute? What scientific questions does he or she want to address? What is their daily work routine? During our regular Lab Tours, female postdocs provide insight into their jobs. They also tell us about their career path: How did they get there? And what do they envision for their professional future? This time, Dr. Ana Guilherme Buzanich, a scientist from the Structure Analysis division at the Bundesanstalt für Materialforschung und -prüfung (BAM), will give an overview of her Research areas. She works at the electron storage ring BESSY-II where she conducts experiments at two hard X-ray beamlines (BAMline and µSpot). The tour includes a guided visit of the research facility. T2 - Lab Tour & Career Talk, WiNS CY - Berlin, Germany DA - 11.02.2019 KW - Women in STEM KW - X-ray Spectroscopy KW - Synchrotron KW - Beamline KW - Material characterization PY - 2019 AN - OPUS4-47418 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gollwitzer, Christian A1 - Scholz, Philipp A1 - Ulbricht, Alexander A1 - Joshi, Yogita A1 - Weidner, Steffen T1 - Synchrotron based absorption edge tomography for the analysis of 3D printed polymer MOF N2 - Absorption edge tomography is a method which exploits the sudden change of the attenuation coefficient, when the photon energy crosses the absorption edge of an element. The beamline BAM line at BESSY II, which is operated by the Federal Institute for Materials Research and Testing, can provide a monochromatized beam in a photon energy range from 5 keV up to 80 keV with a bandwidth of 2%. Together with the microtomography setup, this enables differential tomography sensitive to any element with N >= 24 (Cr) by using an appropriate K- or L-edge in this range. Here, a polymer filament embedding metal organic framework (MOF) was prepared and used for 3D printing. Absorption edge tomography at the copper K edge was employed to perform a non-destructive 3D characterization of the microstructure of the embedded MOF. Data fusion was then used to determine the size distribution of the embedded MOF. T2 - iCT 2019 CY - Padua, Italy DA - 12.02.2019 KW - Synchrotron tomography KW - BAMline KW - MOF KW - Absorption edge tomography PY - 2019 AN - OPUS4-47391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gollwitzer, Christian A1 - Scholz, Philipp A1 - Ulbricht, Alexander A1 - Joshi, Yogita A1 - Weidner, Steffen T1 - Synchrotron based absorption edge tomography for the analysis of 3D printed polymer MOF N2 - Absorption edge tomography is a method which exploits the sudden change of the attenuation coefficient, when the photon energy crosses the absorption edge of an element. The beamline BAM line at BESSY II, which is operated by the Federal Institute for Materials Research and Testing, can provide a monochromatized beam in a photon energy range from 5 keV up to 80 keV with a bandwidth of 2%. Together with the microtomography setup, this enables differential tomography sensitive to any element with N >= 24 (Cr) by using an appropriate K- or L-edge in this range. Here, a polymer filament embedding metal organic framework (MOF) was prepared and used for 3D printing. Absorption edge tomography at the copper K edge was employed to perform a non-destructive 3D characterization of the microstructure of the embedded MOF. Data fusion was then used to determine the size distribution of the embedded MOF. T2 - iCT 2019 CY - Padua, Italy DA - 12.02.2019 KW - Synchrotron tomography KW - BAMline KW - MOF KW - Absorption edge tomography PY - 2019 AN - OPUS4-47392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Domonov, D.P. A1 - Pechenyuk, S.I. A1 - Semushina, Y.P. A1 - Yusenko, Kirill T1 - Solid state transformation in inner coordination sphere of [Co(NH3)6][Fe(C2O4)3]·3H2O as a route to access catalytically active Co-Fe materials N2 - Thermal decomposition of [Co(NH₃)₆][Fe(C₂O₄)₃]∙3H₂O in argon atmosphere, at a low heating rate (3°/min), and in large amounts of the initial complex (~0.1 mole), has been studied. It was possible to distinguish four decomposition steps upon heating: In the temperature range of 50⁻100 °C-the loss of crystal water; 100⁻190 °C-stability region of dehydrated complex; 230⁻270 °C-the range of stability of intermediate phase with the formula CoFe(NH₃)₂(C₂O₄)₂; 270⁻350 °C-thermal decomposition of the intermediate with the formation of metallic products and further air oxidation with the formation of Co1.5Fe1.5O₄. Catalytic properties of thermolysis products were tested in the decomposition reaction of H₂O₂ (inactive), oxidation of acetone (average activity), and decomposition of ammonium perchlorate (highly active). KW - Double complex salts KW - Catalysts KW - Single-source precursors PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474014 DO - https://doi.org/10.3390/ma12020221 SN - 1996-1944 VL - 12 IS - 2 SP - 221, 1 EP - 10 PB - mdpi CY - Zürich AN - OPUS4-47401 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baek, W. A1 - Gromilov, S. A1 - Kuklin, A. A1 - Kovaleva, E. A1 - Fedorov, A. A1 - Sukhikh, Alex A1 - Hanfland, M. A1 - Pomogaev, V. A1 - Melchakova, Y. A1 - Avramov, P. A1 - Yusenko, Kirill T1 - Unique Nanomechanical Properties of Diamond-Lonsdaleite Biphases: Combined Exp and Theor consideration of popigai impact diamonds N2 - For the first time, lonsdaleite-rich impact diamonds from one of the largest Popigai impact crater (Northern Siberia) with a high concentration of structural defects are investigated under hydrostatic compression up to 25 GPa. It is found that, depending on the nature of a sample, the bulk modulus for lonsdaleite experimentally obtained by X-ray diffraction in diamond-anvil cells is systematically lower and equal to 93.3−100.5% of the average values of the bulk moduli of a diamond matrix. Density functional theory calculations reveal possible coexistence of a number of diamond/lonsdaleite and twin diamond biphases. Among the different mutual configurations, separate inclusions of one lonsdaleite (001) plane per four diamond (111) demonstrate the lowest energy per carbon atom, suggesting a favorable formation of single-layer lonsdaleite (001) fragments inserted in the diamond matrix. Calculated formation energies and experimental diamond (311) and lonsdaleite (331) powder X-ray diffraction patterns indicate that all biphases could be formed under high-temperature, high-pressure conditions. Following the equation of states, the bulk modulus of the diamond (111)/lonsdaleite (001) biphase is the largest one among all bulk moduli, including pristine diamond and lonsdaleite. KW - Compressibility KW - Lonsdaleite KW - Impact diamonds PY - 2019 DO - https://doi.org/10.1021/acs.nanolett.8b04421 VL - 19 IS - 9 SP - 1570 EP - 1576 PB - ACS AN - OPUS4-47403 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - You, Zengchao A1 - Jakubowski, Norbert A1 - Panne, Ulrich A1 - Weidner, Steffen T1 - Separation of polystyrene nanoparticles with different coatings using two-dimensional off-line coupling of asymmetrical flow field flow fractionation and capillary electrophoresis N2 - The successful off-line coupling of asymmetrical flow field flow fractionation (AF4) and capillary electrophoresis (CE) for separation of nanoparticles (NPs) with different surface coatings was shown. We could successfully demonstrate that, in a certain NP size range, hyphenation of both techniques significantly improved the separation of differently coated NPs. Three mixtures of polystyrene nanoparticles (PS-NPs) with comparable core sizes but different coatings (no coating/carboxyl-coated) were studied. Separation in either method resulted in non-baseline resolved or non-separated peaks. In contrast, two-dimensional off-line coupling of AF4 and CE resulted in clearly separated regions in their 2 D plots in case of 20 and 50 nm particle mixtures, whereas the 100 nm NP mixture could not be separated at all. Various factors affecting the separation like hydrodynamic diameter or SDS concentration were discussed. KW - Capillary electrophoresis (CE) KW - Nanoparticles with same nominal diameter KW - Surface coating KW - Two-dimensional off-line coupling KW - Asymmetrical flow field flow fractionation (AF4) PY - 2019 DO - https://doi.org/10.1016/j.chroma.2019.01.056 VL - 1593 SP - 119 EP - 126 PB - Elsevier AN - OPUS4-47363 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - de Oliveira Guilherme Buzanich, Ana T1 - Hard X-ray spectroscopy and imaging at the BAMline and MySpot beamlines at BESSY II (Berlin, Germany) N2 - Overview of the X-ray based analytical methods conducted at the BAMline and µSpot Beamline for structure analysis. T2 - Pccr2 + AfLS conference CY - Accra, Ghana DA - 29.01.2019 KW - X-ray spectroscopy KW - Synchrotron KW - Beamline KW - Material characterization PY - 2019 AN - OPUS4-47319 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Emmerling, Franziska T1 - May the Force be with you - Mechanochemical syntheses studied in situ N2 - Mechanochemistry is a fast and efficient method applicable for the synthesis of new organic, metal-organic, and inorganic compounds. The direct monitoring of milling reactions is still challenging. The underlying reaction mechanisms remain often unclear. In the last years, have established a tandem in situ approach for investigating mechanochemical reactions using time-resolved in situ XRD coupled with Raman spectroscopy. Here, we present an in situ coupling of synchrotron XRD, Raman spectroscopy, and thermography allowing the observation of mechanochemical reactions in real time. Information on the crystalline, molecular, and temperature state of the materials during grinding could be collected. The chemical composition of the reaction mixture was found to be directly correlated with changes in the temperature profile of the reaction. Furthermore, the presented setup allows the detection of crystalline, amorphous, eutectic as well as liquid intermediates. The resulting deeper kinetic and thermodynamic understanding of milling processes is the key for future optimization of mechanochemical syntheses. T2 - Seminar Universität Montpellier CY - Montpellier, France DA - 24.01.2019 KW - Mechanochemistry KW - In situ PY - 2019 AN - OPUS4-47261 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Emmerling, Franziska T1 - New insights in mechanochemical processes using real-time in situ investigations N2 - Use of synchrotron radiation for special sample conditions. Recent work of the group at BESSY II. T2 - DESY Usermeeting Satelite Workshop CY - Hamburg, Germany DA - 22.01.2019 KW - XRD KW - In situ KW - Rietveld KW - Synchrotron PY - 2019 AN - OPUS4-47262 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Lauer, F. A1 - Seifert, S. A1 - Diehn, S. A1 - Kneipp, Janina T1 - MALDI-TOF MS und MALDI-MSI zur Identifikation und Klassifizierung von Pollen N2 - Es werden die letzten Ergebnisse präsentiert, die es ermöglichen, einzelne Pollenkörner unterschiedlicher Arten in Mischungen mittels MALDI-TOF Massenspektrometrie bzw. MALDI-TOF Imaging zu messen und unter Zuhilfenahme multivariater Auswertemethoden zu klassifizieren. T2 - 24. Bruker MALDI Anwendertreffen CY - Leipzig, Germany DA - 18.02.2019 KW - MALDI-TOF Massenspektrometrie KW - Pollenkörner KW - Klassifizierung KW - MALDI Imaging KW - Multivariate Analyse PY - 2019 AN - OPUS4-47441 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radtke, Martin A1 - de Oliveira Guilherme Buzanich, Ana A1 - Reinholz, Uwe A1 - Emmerling, Franziska T1 - Materials research with synchrotron radiation N2 - Synchrotron radiation sources with their unique properties in terms of intensity, polarization and adjustability offer a wide range of possibilities in materials research. A basic introduction about the creation and special properties of synchrotron radiation will be given. Examples of current work at BAMline, the high-energy measuring facility of the Federal Institute for Materials Research and Testing at the synchrotron BESSY, are used to illustrate the possibilities and limitations of existing measuring methods. It will be shown how the formation of corrosion layers can be tracked, how the abrasion of implants leads to the introduction of heavy metals into the surrounding bone matrix and how the detection of smallest impurities in gold is possible by optimizing the measuring conditions. Finally, an outlook at the hardware and software developments to be expected in the coming years is given. T2 - INCT-FNA Symposium 2019 CY - Niteroi, Brazil DA - 27.05.2019 KW - Synchrotron KW - XRF KW - XANES KW - EXAFS KW - TXRF KW - Color X-ray Camera PY - 2019 AN - OPUS4-48897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fittschen, U.E.A. A1 - Möckel, R. A1 - Schreiner, M. A1 - klinger, M. A1 - Radtke, Martin A1 - Meyer, B. A1 - Guhl, S. A1 - Renno, A. A1 - Godinho, J. A1 - Gloaguen, R. A1 - Gutzmer, J. T1 - Bundling analytical capacities to understand phase formation in recycling of functional materials N2 - Transitioning from combustion engine-driven transportation to e-mobility demands a paradigm shift – from a system geared to maximize energy efficiency (i.e. fuel consumption) to a system that may be constrained by the availability of high technology (critical) metals required for electrical energy storage systems and drives. In the wake of these developments efforts in securing new resources of these metals from recycling of end-of-life products are increasing steadily. Recycling of Li-Ion batteries has recently been evaluated. The results pinpoint to a critical need for understanding slag Formation and its dependence on metal components like Mn under extreme conditions. This will allow researchers to predict optimal Operation setting and to react quickly to changing market demands (which may be Li or Co at one point but may also shift to Ni or rare earth elements (REE)). The long-term goal is to control the formation of specific phases in slags allowing for a Maximum yield of elements of interest and optimal recovery in the separation processes that follows. The combination of data on the physical micro structure and local chemistry of the multi-Phase products during and after processing will help to understand and derive thermodynamic and kinetic data on its formation. In this paper we are giving an overview on the analytical challenges and approaches to provide robust data on local element concentration and species (especially Mn which is a common component of next generation Li-ion batteries cathodes), spanning the dimensions from the nanometer scale to the bulk material. The complementary interactions of X-rays and electrons make them ideal probes to collect Interface and “in-depth” information. Before- and -after studies as well as in situ structural changes and Phase (trans)formation, changes in elemental and elemental species (e.g. oxidation state) distribution may be tracked by X-ray diffraction (XRD), X-ray fluorescence microscopy and X-ray Absorption spectroscopy. The application of such advanced analytical tools will not only provide essential clues during early lab-based experiments towards the development of new recycling technologies, but may also be deployed for on-line and in-line monitoring of industrial processes. KW - Synchrotron KW - XANES KW - Slags KW - Battery PY - 2019 DO - https://doi.org/10.4028/www.scientific.net/MSF.959.183 SN - 1662-9752 VL - 959 SP - 183 EP - 190 PB - Trans Tech Publ. AN - OPUS4-48900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radtke, Martin T1 - Machine learning for direct quantification of XRF measurements N2 - In X-ray fluorescence (XRF), a sample is excited with X-rays, and the resulting characteristic radiation is detected to detect elements quantitatively and qualitatively. Quantification is traditionally done in several steps: 1. Normalization of the data 2. Determination of the existing elements 3. Fit of the measured spectrum 4. Calculation of concentrations with fundamental parameters / MC simulations / standard based The problem with standard based procedures is the availability of corresponding standards. The problem with the calculations is that the measured intensities for XRF measurements are matrix-dependent. Calculations must, therefore, be performed iteratively (= time consuming) in order to determine the chemical composition. First experiments with gold samples have shown the feasibility of machine learning based quantification in principle. A large number of compositions were simulated (> 10000) and analyzed with a deep learning network. For first experiments, an ANN (Artificial Neural Network) with 3 hidden layers and 33x33x33 neurons was used. This network learned the mapping of spectra to concentrations using supervised learning by multidimensional regression. The input layer was formed by the normalized spectrum, and the output layer directly yielded the searched values. The applicability for real samples was shown by measurements on certified reference materials. T2 - Denver X-ray Conference CY - Lombard, IL, USA DA - 05.08.2019 KW - Machine learning KW - Artificial intelligence KW - Neural network KW - XRF KW - Synchrotron PY - 2019 AN - OPUS4-48903 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gao, S. A1 - Hou, J. A1 - Deng, Z. A1 - Wang, T. A1 - Beyer, Sebastian A1 - de Oliveira Guilherme Buzanich, Ana A1 - Richardson, J. J. A1 - Rawal, A. A1 - Seidel, R. A1 - Zulkifli, M. Y. A1 - Li, W. A1 - Bennett, T. D. A1 - Cheetham, A. K. A1 - Liang, K. T1 - Improving the Acidic Stability of Zeolitic Imidazolate Frameworks by Biofunctional Molecules N2 - Zeolitic imidazolate frameworks (ZIFs) have been widely investigated for their use in separation, gas adsorption, catalysis, and biotechnology. Their practical applications, however, can be hampered by their structural instability in humid acidic conditions. Here, guided by density functional theory calculations, we demonstrate that the acidic stability of two polymorphic ZIFs (i.e., ZIF-8 and ZIF-L) can be enhanced by the incorporation of functional groups on polypeptides or DNA. A range of complementary synchrotron investigations into the local chemical structure and bonding environment suggest that the enhanced acidic stability arises from the newly established coordinative interactions between the Zn centers and the inserted carboxylate (for polypeptides) or phosphate (for DNA) groups, both of which have lower pKas than the imidazolate ligand. With functional biomolecular homologs (i.e., enzymes), we demonstrate a symbiotic stability reinforcement effect, i.e., the encapsulated biomolecules stabilize the ZIF matrix while the ZIF exoskeleton protects the enzyme from denaturation. KW - Zeolitic Imidazolate Frameworks KW - Biofunctional Molecules KW - X-ray Absorption Spectroscopy PY - 2019 DO - https://doi.org/10.1016/j.chempr.2019.03.025 VL - 5 IS - 6 SP - 1597 EP - 1608 PB - Elsevier Inc. AN - OPUS4-48702 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kulow, Anicó A1 - Radtke, Martin A1 - de Oliveira Guilherme Buzanich, Ana A1 - Streli, C. T1 - X-ray fluorescence imaging with coded apertures N2 - Our aim is to develop a new method for full field X ray fluorescence imaging at the BAM line @ BESSY II. We will combine an energydispersive array detector for X rays with a coded aperture to get high resolution images . In coded aperture imaging , an object is projected through a mask , producing many overlapping images on the detector . The first part of the project is to perform raytracing simulations to get realistic data and to develop a reconstruction method that allows to get the Information about the investigated object out of the projected image . T2 - Symposium "IRIS 2019" CY - Berlin, Germany DA - 24.10.2019 KW - X-ray spectroscopy KW - X-ray fluorescence KW - Imaging KW - Coded Apertures PY - 2019 AN - OPUS4-49434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stroh, Julia A1 - Feiler, Torvid A1 - Ali, N. Z. A1 - Minas da Piedade, M. E. A1 - Emmerling, Franziska T1 - Mechanistic Insights into a Sustainable Mechanochemical Synthesis of Ettringite N2 - Mechanochemistry offers an environmentally benign and facile synthesis method for a variety of cement paste constituents. In addition, these methods can be used to selectively tune the properties of cement components. The mineral ettringite is an important component of cementitious materials and has additional technological potential due to its ion exchange properties. Synthesis of ettringite via mechanochemistry is an environmentally friendly alternative to conventional wet-chemical synthesis established in industry. This contribution explores the mechanism of a two-step mechanochemical synthesis of ettringite, which was previously found to greatly improve the reaction conversion as compared with one-pot synthesis. The crystallinity of Al(OH)3 was found to decrease during the first stage of this mechanochemical synthesis. This was correlated to a significant decrease in the particle size of Al(OH)3 in this stage. No other significant changes were found for the other components, suggesting that mechanochemical activation of Al(OH)3 is responsible for the enhanced formation of ettringite by the two-step approach. The environmentally friendly approach developed for ettringite synthesis offers a versatile synthetic strategy, which can be applied to synthesise further cementitious materials. KW - Ettringite KW - Mechanochemistry KW - Sustainability KW - X-ray diffraction PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-489172 DO - https://doi.org/10.1002/open.201900215 VL - 8 IS - 7 SP - 1012 EP - 1019 PB - ChemPubSoc AN - OPUS4-48917 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kulow, Anicó A1 - de Oliveira Guilherme Buzanich, Ana A1 - Reinholz, Uwe A1 - Radtke, Martin A1 - Riesemeier, Heinrich A1 - Streli, C. T1 - Time- and lateral-resolved X-ray absorption fine structure spectroscopy N2 - We developed a setup for time- and lateral-resolved X-ray absorption fine structure (XAFS) spectroscopy. A dispersive element is placed behind the sample to investigate. The broadband incoming beam transmits the sample, is then dispersed and finally collected by a position sensitive detector. This allows the recording of a whole X-ray absorption near edge structure (XANES) or extended X-ray absorption fine structure (EXAFS) spectrum in a single shot. The dispersive element is a Si(111) crystal, bent by means of a so called wafer bender, developed in house. Our setup is very flexible, easy to adjust and allows a time resolution down to one second which can be used to follow chemical reactions with dynamics on this time scale. T2 - SXR2019 CY - Berlin, Germany DA - 16.09.2019 KW - Spectroscopy KW - X-ray KW - Absorption KW - Synchrotron PY - 2019 AN - OPUS4-49045 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - De Samber, B. A1 - Scharf, Oliver A1 - Buzanich, Günter A1 - Garrevoet, J. A1 - Tack, P. A1 - Radtke, Martin A1 - Riesemeier, Heinrich A1 - Reinholz, Uwe A1 - Evens, R. A1 - De Schamphelaere, K. A1 - Falkenberg, G. A1 - Janssen, C. A1 - Vincze, L. T1 - Three-dimensional X-ray fluorescence imaging modes for biological specimens using a full-field energy dispersive CCD camera N2 - Besides conventional scanning X-ray fluorescence imaging at synchrotron sources, full-field X-ray fluorescence (FF-XRF) imaging techniques that do not implicitly require spatial scanning of the sample have become available. FF-XRF has become achievable thanks to the development of a new type of energy dispersive CCD-based 2D detector, also referred to as a 'color X-ray camera (CXC)' or 'SLcam'. We report on different imaging schemes for biological samples using FF-XRF imaging: (a) 2D 'zoom' imaging with pinhole optics using the 'camera obscura' principle; (b) 2D 'fixed magnification' imaging using magnifying polycapillary optics; and (c) 3D-FF-XRF imaging using an X-ray sheet beam or computed tomography (CT). The different FF-XRF imaging modes are illustrated using the crustacean Daphnia magna, a model organism for investigating the effects of metals on organism/ecosystem health, and foraminifera, a class of amoeboid protist. Detailed analytical characterization of the set-up is performed through analyzing various reference materials in order to determine limits of detection (LODs) and sensitivities. Experiments were performed using the BAMline at the BESSY synchrotron (Berlin, Germany) and using the P06 Hard X-ray Microprobe at the PETRAIII synchrotron (Hamburg, Germany). KW - CXC KW - BAMline KW - Maia detector KW - Synchrotron PY - 2019 DO - https://doi.org/10.1039/c9ja00198k VL - 34 IS - 10 SP - 2083 EP - 2093 PB - Royal Society of Chemistry CY - Cambridge, United Kingdom AN - OPUS4-49359 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stroh, Julia A1 - Ali, Naveed Zafar A1 - Maierhofer, Christiane A1 - Emmerling, Franziska T1 - Ettringite via Mechanochemistry: A Green and Rapid Approach for Industrial Application N2 - Here, we report on a first mechanochemical synthesis of ettringite, an important cement hydrate phase. The mineral compound ettringite ([Ca3Al(OH)6]2·(SO4)3·26H2O) occurs rarely in nature, but is common for cement-based materials. Ettringite has wide technical application in the ceramic and paper industry. However, its typical wet-chemical synthesis is cumbersome and produces waste water and CO2 emissions. Here, we investigate the first mechanochemical synthesis of ettringite for developing an easy and sustainable alternative for industrial application. The mechanosynthesis was monitored in situ by coupled synchrotron X-ray diffraction (XRD) and infrared thermography (IRT). The consumption of the reactants and the formation of the reaction product were monitored with time-resolved XRD. IRT showed the temperature increase based on the exothermic reaction. The reaction conversion was significantly improved changing the strategy of the mechanosynthesis from a one- to a two-step process. The latter included neat pregrinding of solid reactants followed by a delayed addition of the stoichiometric amount of water. Thus, an increase of reaction conversion from 34 to 94% of ettringite could be achieved. KW - XRD KW - Mechanochemistry KW - Ettringite KW - In situ PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479016 DO - https://doi.org/10.1021/acsomega.9b00560 SN - 2470-1343 VL - 4 IS - 4 SP - 7734 EP - 7737 PB - ACS Publications CY - Washington, DC AN - OPUS4-47901 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Xue, Boyang A1 - Riedel, Jens A1 - Gornushkin, Igor B. A1 - Zheng, R. A1 - You, Yi T1 - High-throughput underwater elemental analysis through optical emission spectroscopy with ultrasound-assisted μJ-laser-induced breakdown at kHz repetition rate N2 - The elemental analysis of seawater is often critical to the understanding of marine chemistry, marine geochemistry, and the deep-sea ecosystems. Laser-induced breakdown spectroscopy (LIBS) with the advantage of rapid multi-elements detection, has a great potential for in-situ elemental analysis of seawater. In practice, it is crucial to create a compact, low cost and power saving instrument for the long-term deep-sea observation. A recently appeared diode-pumped solid-state (DPSS) laser seems to be a promising candidate as it is both compact and robust. Additionally, its high repetition rate up to hundreds of kHz can provide a considerable throughput for LIBS analysis. However, the DPSS lasers operate at moderate pulse energies, usually less than one mJ, which cannot sustain stable breakdowns in bulk water. To ensure stable laser-induced plasmas underwater with such a μJ-DPSS laser, we introduced an ultrasound source to assist the breakdown process. The phase interface and mass flow generated by the near-field ultrasound can greatly reduce the breakdown threshold and enhance element-specific emissions. Meanwhile, the high repetition-rate pulses can also improve the breakdown probability and generate unique emission lines originated from the water molecule. We further demonstrate that the high repetition-rate DPSS laser combined with the Echelle spectrometer can provide effective quantitative analysis for metal elements in bulk water. T2 - 10th Euro-Mediterranean Symposium on Laser-Induced Breakdown Spectroscopy, EMSLIBS 2019 CY - Czech, Brno DA - 08.09.2019 KW - Ultrasound KW - Underwater LIBS KW - µJ-DPSS laser KW - High repetition-rate PY - 2019 AN - OPUS4-49223 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lüdecke, Nils A1 - Weidner, Steffen A1 - Schlaad, Helmut T1 - Poly(2‐oxazoline) s Based on Phenolic Acids N2 - A series of phenolic-acid-based 2-oxazoline monomers with methoxysubstituted phenyl and cinnamyl side chains is synthesized and polymerized in a microwave reactor at 140 °C using methyl tosylate as the initiator. The obtained poly(2-oxazoline)s are characterized by NMR spectroscopy, MALDITOF mass spectrometry, and size-exclusion chromatography (SEC). Kinetic studies reveal that the microwave-assisted polymerization is fast and completed within less than ≈10 min for low monomer-to-initiator ratios of ≤25. Polymers with number-average molar masses of up to 6500 g mol−1 and low dispersity (1.2–1.3) are produced. The aryl methyl ethers are successfully cleaved with aluminum triiodide/N,N′ diisopropylcarbodiimide to give a poly(2-oxazoline) with pendent catechol groups. KW - 2-oxazoline KW - Catechol KW - Cationic ring opening polymerization KW - Microwave KW - Phenolic acid PY - 2019 DO - https://doi.org/10.1002/marc.201900404 SP - 1900404 PB - Wiley VCH-Verlag AN - OPUS4-49396 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scholz, Philipp A1 - Ulbricht, Alexander A1 - Joshi, Y. A1 - Gollwitzer, Christian A1 - Weidner, Steffen T1 - Microstructure of polymer-imprinted metal–organic frameworks determined by absorption edge tomography N2 - Mechanochemically synthesized metal–organic Framework material HKUST-1 in combination with acrylonitrile butadiene styrene polymer was used to form a polymer metal–organic framework composite material by a simple extruder. This composite filament was used for 3D printing. Xray diffraction measurements were used to prove the homogeneous distribution of the metal–organic framework in the polymer on a centimeter scale, whereas X-ray Absorption Edge Tomography using a synchrotron radiation source was able to evaluate the 3D distribution of the metal–organic framework material both in the filament and the resultant printed sample with a resolution of a few lm. Our very first data indicate that, apart from a few clusters having significantly higher Cu concentration, HKUST-1 is distributed homogeneously down to the 100 lm length scale in both polymer bulk materials in the form of clusters with a size of a few lm. Absorption Edge Tomography in combination with data fusion also allows for the calculation of the metal–organic framework amount located on the external polymer surface. KW - MOF KW - Polymer KW - AET PY - 2019 DO - https://doi.org/10.3139/146.111817 SN - 1862-5282 SP - 1 EP - 10 PB - Carl Hanser Verlag AN - OPUS4-49483 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lumpe, H. A1 - Menke, A. A1 - Haisch, C. A1 - Mayer, P. A1 - Kabelitz, Anke A1 - Yusenko, Kirill A1 - de Oliveira Guilherme Buzanich, Ana A1 - Block, T. A1 - Pöttgen, R. A1 - Emmerling, Franziska A1 - Daumann, L. J. T1 - The Earlier the Better: Structural Analysis and Separation of Lanthanides with Pyrroloquinoline Quinone N2 - Lanthanides (Ln) are critical raw materials, however, their mining and purification have a considerable negative environmental impact and sustainable recycling and separation strategies for these elements are needed. In this study, the precipitation and solubility behavior of Ln complexes with pyrroloquinoline quinone (PQQ), the cofactor of recently discovered lanthanide (Ln) dependent methanol Dehydrogenase (MDH) enzymes, is presented. In this context, the molecular structure of a biorelevant europium PQQ complex was for the first time elucidated outside a protein environment. The complex crystallizes as an inversion symmetric dimer, Eu2PQQ2, with binding of Eu in the biologically relevant pocket of PQQ. LnPQQ and Ln1Ln2PQQ complexes were characterized by using inductively coupled Plasma mass spectrometry (ICP-MS), infrared (IR) spectroscopy, 151Eu-Mössbauer spectroscopy, X-ray total scattering, and Extended X-ray absorption fine structure (EXAFS). It is shown that a natural enzymatic cofactor is capable to achieve Separation by precipitation of the notoriously similar, and thus difficult to separate, lanthanides to some extent. KW - Lanthanides KW - Structural Analysis KW - Separation PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510821 DO - https://doi.org/10.1002/chem.202002653 SN - 0947-6539 VL - 26 SP - 1 EP - 8 PB - WILEY-VCH Verlag GmbH & co. KGaA AN - OPUS4-51082 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen T1 - High molar mass cyclic poly(L-lactide)s by means of neat tin (II) 2-ethylhexanoate N2 - L-lactide was polymerized in bulk at 120, 140, 160 and 180°C with neat tin(II) 2-ethylhexanoate (SnOct2) as catalyst. At 180°C the Lac/Cat ratio was varied from 25/1 up to 8 000/1 and at 160°C from 25/1 up to 6 000/1. The vast majority of the resulting polylactides consist of cycles in combination with a small fraction of linear chains having one octanoate and one COOH end group. The linear chains almost vanished at high Lac/Cat ratios, as evidenced by MALDI-TOF mass spectrometry and measurements of intrinsic viscosities and dn/dc values. At Lac/Cat ratios <1000/1 the number average molar masses (Mn) are far higher than expected for stoichiometic initiation, and above 400/1 the molar masses vary relatively little with the Lac/Cat ratio. At 180° slight discoloration even at short times and degradation of the molar masses were observed, but at 160°C or below colorless products with weight average molar masses (Mw) up to 310 000 g mol-1 were obtained. The formation of high molar mass cyclic polylactides is explained by a ROPPOC (Ring-Opening Polymerizatiom with simultaneous Polycondensation) mechanism with intermediate formation of linear chains having one Sn-O-CH end group and one mixed anhydride end group. Additional experiments with tin(II)acetate as catalyst confirm this interpretation. These findings together with the detection of several transesterification mechanisms confirm previous critique of the Jacobson-Stockmayer theory. KW - Polylactide KW - MALDI-TOF MS KW - Cyclization PY - 2020 DO - https://doi.org/10.1039/d0py00811g VL - 11 IS - 32 SP - 5249 EP - 5260 PB - Royal Society for Chemistry AN - OPUS4-51130 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen T1 - The Ring-Opening Polymerisation-Polycondensation (ROPPOC) Approach to cyclic Polymers N2 - A new concept called “Ring-Opening Polymerization (ROP) combined with simultaneous POlyCondensation” (ROPPOC) is presented and discussed. This synthetic strategy is based on the intermediate formation of chains having two end groups that can react with each other. The ROPPOC syntheses are subdivided into three groups according to the nature of the chain ends: two ionic end groups, one ionic and one covalent chain end and a combination of two reactive covalent end groups may be involved, depending on the catalyst. The usefulness for the preparation of cyclic polymers is discussed with a review of numerous previously published examples. These examples concern to following classes of cyclic polymers: polypeptides, polyamides, polyesters, including polycarbonates, and cyclic polysiloxanes. It is demonstrated, that the results of certain ROPPOC syntheses are in contradiction to the Jacobson-Stockmayer theory. Finally, the usefulness of ROPPOCs for the detection of polydisperse catenanes is discussed. KW - Ring-opening Polymerisation KW - MALDI-TOF MS KW - ROPPOC KW - Cyclic PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508509 DO - https://doi.org/10.1002/marc.202000152 SP - 2000152 PB - Wiley AN - OPUS4-50850 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Kricheldorf, H. R. T1 - Differences in MALDI Ionization of neat linear and cyclic poly(L-lactide)s N2 - In addition to molar mass distribution (MMD) synthetic polymers often exhibit an additional chemical heterogeneity distribution, expressed by different end groups and other structural variations (e.g. tacticity, copolymer composition etc.). Ionization in MALDI MS is always strongly affected by such chemical properties. For example, the abundance of cyclics in MALDI TOF mass spectra is frequently reported to greatly exceed that of linears. Thus, the MALDI ionization behavior of various neat end-capped linear poly(L-lactide)s and one cyclic poly(L-lactide) was investigated and compared with that of blends of both structures. Moreover, the influence of the cationizing salt was investigated too. Neat compounds and various blends of cyclic and linear species were prepared and studied using two MALDI TOF mass spectrometers under identical conditions with regard to sample preparation and instrumental conditions, except for the laser power and the salt used for cationization. Polymer samples were additionally characterized by NMR and SEC. The steady increase of the laser intensity caused an exponential increase of the peak intensities of both linear and cyclic polylactides.The response of linear polylactides (in the investigated molecular mass range), whether as neat polymer or in blends with other linear polylactides was almost similar. This clearly supports our assumption that ionization in MALDI is probably unaffected by the end group structure.The variation of the laser power shows only little effect on the intensity ratio of linear-to linear and cyclic-to-linear polylactides in blends. Whereas neat linear polylactides at all laser intensities have a significantly higher abundance than neat cyclics, in mixtures of both an overestimation of cyclic species in MALDI TOF mass spectra of polylactides was found. However, this is far less distinct than frequently reported for other polymers.Concluding, peak suppression of linear polymers in mixtures of both architectures can be excluded, which also means, that polylactides showing only peaks of cyclic compounds in their MALDI - TOF mass spectra do not contain a significant fraction of linear analogues. Our study is the first systematic comparison of the MALDI ionization of neat and blended cyclic and linear polylactides. T2 - ASMS 2020 Reboot CY - Online meeting DA - 01.06.2020 KW - MALDI KW - Ionization KW - Linear KW - Cyclic KW - Polylactide PY - 2020 AN - OPUS4-50852 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reifschneider, O. A1 - Vennemann, A. A1 - Buzanich, Günter A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Riesemeier, Heinrich A1 - Hogeback, J A1 - Köppen, C. A1 - Großgarten, M. A1 - Sperling, M. A1 - Wiemann, M. A1 - Karst, U. T1 - Revealing Silver Nanoparticle Uptake by Macrophages Using SR-μXRF and LA-ICP-MS N2 - To better study the impact of nanoparticles on both in vitro and in vivo models, tissue distribution and cellular doses need to be described more closely. Here silver nanoparticles were visualized in alveolar macrophages by means of synchrotron radiation micro X-ray fluorescence spectroscopy (SR-μXRF) with high spatial resolution of 3 × 3 μm2. For the spatial allocation of silver signals to cells and tissue structures, additional elemental labeling was carried out by staining with eosin, which binds to protein and can be detected as bromine signal with SR-μXRF. The method was compatible with immunostaining of macrophage antigens. We found that the silver distribution obtained with SR-μXRF was largely congruent with distribution maps from a subsequent laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of the same tissue sites. The study shows a predominant, though not exclusive uptake of silver into alveolar macrophages in the rat lung, which can be modeled by a similar uptake in cultured alveolar macrophages. Advantages and limitations of the different strategies for measuring nanoparticle uptake at the single cell level are discussed. KW - Synchrotron KW - BAMline KW - XRF KW - Nanoparticle KW - Macrophagen PY - 2020 DO - https://doi.org/10.1021/acs.chemrestox.9b00507 VL - 33 IS - 5 SP - 1250 EP - 1255 PB - American Chemical Society AN - OPUS4-50855 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rautenberg, Max A1 - Bhattacharya, Biswajit A1 - Akhmetova, Irinia A1 - Emmerling, Franziska T1 - Mechanochemical and solution syntheses of two novel cocrystals of orcinol with two N,N0-Dipyridines: Structural diversity with varying ligand flexibility N2 - We studied the influence of coformers flexibility on the supramolecular assembly of 5-substituted resorcinol. Two cocrystals of orcinol (ORL) with two dipyridine molecules, i.e. 1,2-di(4-pyridyl)ethane (ORLeBPE) and 1,2-di(4-pyridyl)ethylene (ORLeBPY), were prepared by mechanochemical synthesis and slow evaporation of solvent. The new crystalline solids were thoroughly characterized by single crystal Xray diffraction (SCXRD), powder X-ray diffraction analysis (PXRD), Fourier-transform infrared spectroscopy (FT-IR), differential thermal analysis (DTA), and thermogravimetric analysis (TGA). Structural determination reveals that in both cocrystals, the phenolepyridine, i.e. OeH/N(py) heterosynthon takes the main role in the formation of cocrystals. In ORLeBPE, the components form infinite 1D zig-zag chains, which are extended to 2D layer structure by inter-chain CeH/O interactions between BPE hydrogen atoms and hydroxyl oxygen atoms of ORL. In ORLeBPY, the components form a 0D fourcomponent complex. Formation of the discrete assemblies is attributed to the comparative rigid nature of BPY, which restricts the formation of an extended network. KW - Cocrystal KW - Single crystal KW - X-ray diffraction KW - Mechanochemistry PY - 2020 DO - https://doi.org/10.1016/j.molstruc.2020.128303 SN - 0022-2860 VL - 1217 SP - 128303 PB - Elsevier B.V. AN - OPUS4-51023 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kervarec, M.-C. A1 - Kemnitz, E. A1 - Scholz, G. A1 - Rudic, S. A1 - Jäger, Christian A1 - Braun, T. A1 - Michalchuk, Adam A1 - Emmerling, Franziska T1 - A HF Loaded Lewis-Acidic Aluminium Chlorofluoride for Hydrofluorination Reactions N2 - The very strong Lewis acid aluminium chlorofluo-ride (ACF) was loaded with anhydrous HF. The interactionbetween the surface of the catalyst and HF was investigatedusing a variety of characterization methods, which revealed he formation of polyfluorides. Moreover, the reactivity ofthe HF-loaded ACF towards the hydrofluorination of alkyneswas studied. KW - Aluminium KW - HF KW - Hydrofluorination KW - Metal fluorides PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508360 DO - https://doi.org/10.1002/chem.202001627 VL - 26 SP - 1 PB - Wiley Online Libary AN - OPUS4-50836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - da Silva, D.A. A1 - Greiser, Sebastian A1 - Contro, J. A1 - Medeiros, V.L. A1 - Nery, J.G. A1 - Jäger, Christian T1 - 1H, 29Si and 119Sn double and triple resonance NMR spectroscopy of the small-pore framework sodium stannosilicate Na2SnSi3O9⋅2H2O N2 - The small-pore framework sodium stannosilicate AV-10, chemical composition Na2SnSi3O9⋅2H2O and known crystallographic structure, was synthesized by hydrothermal crystallization. This stannosilicate is built up of a three-dimensional network of corner-shared SiO4 tetrahedra and SnO6 octahedra. The SnO6 sites are linked to six SiO4 tetrahedra (Sn(6Si)) while each of the two crystallographically different SiO4 units are connected to two SnO6 and SiO4 units (Si(2Si,2Sn)). This material was used as model compound for developing a solid-state MAS NMR strategy aimed on the challenges and possibilities for structural studies, particularly considering the short and medium range order to verify the connectivity of SiO4 and SnO6 of such compounds despite the low natural abundances of 4.68% for 29Si and 8.59% for 119Sn nuclei as a real challenge. 29Si{119Sn} and 119Sn{29Si} REDOR (Rotational-Echo Double-Resonance) NMR measurements after 1H cross-polarization (CP) were carried out. The REDOR curves show a significant change after the “normal” quadratic short time evolution from which both (i) the shortest internuclear 29Si – 119Sn distances (and vice versa) and (ii) the number of corner-sharing SiO4 tetrahedra around the SnO6 octahedra (and vice versa) can be obtained. Based on these data, optimized 29Si {119Sn} and 119Sn{29Si} REPT-HMQC (Recoupled Polarization Transfer-Heteronuclear Multiple-Quantum Correlation, again after 1H CP) experiments were implemented, which directly show those heterogroup connectivity as correlation peaks in a 2D spectrum. This information was also obtained using 2D29Si{119Sn}-J-Coupling NMR experiments. Furthermore, 2D29Si INADEQUATE NMR experiments are also feasible, showing the connectivity of SiO4 tetrahedra. The combination of REDOR, REPT-HMQC, J-Coupling and INADEQUATE experiments yielded a complete analysis of the short and medium range structure of this microporous stannosilicate, in agreement with the previously published structure obtained Ab Initio from powder X-Ray diffraction data (XRD). KW - Stannosilicates KW - REDOR KW - REPT-HMQC KW - INADEQUATE PY - 2020 DO - https://doi.org/10.1016/j.ssnmr.2020.101661 SN - 0926-2040 VL - 107 SP - 101661 PB - Elsevier Inc. AN - OPUS4-50710 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kanwal, S. A1 - Ali, Naveed Zafar A1 - Hussain, R. A1 - Shah, F.U. A1 - Akhter, Z. T1 - Poly-thiourea formaldehyde based anticorrosion marine coatings on Type 304 stainless steel N2 - In the present study, hexamethylene diisocyanate (HMDI) encapsulated poly-thiourea formaldehyde (PTF) (10 wt%) coating was developed in an epoxy-polyamine matrix and their anticorrosion studies on Type SS304 stainless steel substrate have been conducted using electrochemistry techniques. The compact and hydrophobic shell wall of PTF proved to be a potent shell wall material for HMDI encapsulation. The effect of temperature and pH values was found to be decisive factor in the synthesis of microcapsules. The PTF microcapsules were synthesized in acidic condition with a pH value of 3. Over 90% of the core fraction is retained in water after 21 days immersion. However, core content decreased with increasing temperature. The capsules were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Electrochemical Impedance spectroscopy (EIS). Scanning electron microscopic analysis depicts the uniform morphology of coating with a particle size in the range of 1.08 µm–22.06 µm. The vibrational band at 2271 cm−1 attributed to NCO signal further endorses the successful encapsulation of HMDI into the PTF capsules. Electrochemical testing on steel specifies the appreciable anticorrosion performance of the synthesized poly thiourea formaldehyde (PTF) coating against artificial sea water. KW - In-situ polymerization KW - Encapsulation KW - Thiourea-formaldehyde KW - Marine corrosion PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507932 DO - https://doi.org/10.1016/j.jmrt.2019.12.045 VL - 9 IS - 2 SP - 2146 EP - 2153 PB - Elsevier B.V. AN - OPUS4-50793 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen A1 - Scheliga, F. T1 - Synthesis of cyclic polymers and flaws of the Jacobson–Stockmayer theory N2 - Cyclic poly(L-lactide)s were prepared by ring-opening polymerization combined with simultaneous polycondensation (ROPPOC) in bulk at 160 ° with dibutyltin bis(4-cyanophenoxide) as catalyst. It is demonstrated by MALDI TOF mass spectrometry and 1H NMR end group analyses that cycles are formed by endto-end cyclization in addition to “back-biting” transesterification. Formation of high molar mass cyclic poly L-lactide)s by means of several more reactive ROPPOC catalysts presented previously and in new experiments is discussed. These experimental results, together with theoretical arguments, prove that part of the Jacobson–Stockmayer theory is wrong. The critical monomer concentration, above which end-toend cyclization is seemingly impossible, does not exist and reversible like irreversible polycondensations can theoretically proceed up to 100% conversion, so that finally all reaction products will necessarily adopt a cyclic architecture. KW - Polylactide KW - MALDI-TOF MS KW - Cyclization PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506419 DO - https://doi.org/10.1039/d0py00226g VL - 11 IS - 14 SP - 2595 EP - 2604 PB - Royal Society for Chemistry AN - OPUS4-50641 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Meyer, A. A1 - Kricheldorf, H. R. T1 - Ring–Ring Equilibration in Solid, Even-Numbered Cyclic Poly(l-lactide)s and their Stereocomplexes N2 - Even-numbered cyclic poly(d-lactide) and poly(l-lactide) are prepared by ringexpansion polymerization. The cyclic pol(l-lactide) is annealed either at 120 or at 160 °C for several days. The progress of transesterification in the solid state is monitored by the formation of odd-numbered cycles via matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The changes of the crystallinity are monitored by differential scanning calorimetry, wideand small-angle x-ray scattering (WAXS and SAXS) measurements. Despite total even-odd equilibration at 160 °C, the crystallinity of poly(l-lactide) is not reduced. Furthermore, the crystallinity of the stereocomplexes of both cyclic polylactides do not decrease or vanish, as expected, when a blocky or random stereosequence is formed by transesterification. This conclusion is confirmed by 13C NMR spectroscopy. These measurements demonstrate that transesterification is a ring–ring equilibration involving the loops on the surfaces of the lamellar crystallites thereby improving crystallinity and 3D packing of crystallites without significant broadening of the molecular weight distribution. KW - Polylactide KW - MALDI-TOF MS KW - Cyclization PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506458 DO - https://doi.org/10.1002/macp.202000012 VL - 221 IS - 9 SP - 2000012 PB - Wiley-VCH Verlag AN - OPUS4-50645 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Marquardt, Julien A1 - Frisch, M. A1 - Kiske, S. A1 - Bernicke, M. A1 - Raza, H. A1 - Pinna, N. A1 - Kraehnert, R. A1 - Emmerling, Franziska T1 - Investigating the morphology of nanostructured mixed metal oxides (Ir/TiOx) and its impact on the electrocatalytic OER-activity N2 - The electrocatalytic conversion of water into molecular hydrogen and oxygen under the utilization of excess renewable energies, such as wind power, photovoltaics and hydroelectric power is one possible pathway to establish a sustainable hydrogen economy. The obtained hydrogen is either stored and used in a fuel cell or consumed on-site in industrial applications. Water electrolysis systems (WES) are based on two half cell reactions, such as oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) which both proceed simultaneously. The OER suffers from slow reaction kinetics and thus limits the overall performance. The most promising compounds in acidic electrolysis are IrO2 and RuO2. Due to their rare abundance and extremely high price a wide use of acidic WES was prevented. Lowering the catalysts noble metal content by mixing iridium with titanium reduces the production costs. Thin films are produced by dip coating a solution of metal oxide precursors alongside with a polymer template dissolved in ethanol. The obtained samples are subsequently calcined to the remove the template and adjust crystallinity. Finally, an additional iridium deposition step was performed on the outer surface plane area. Understanding the influence of structural and morphological aspects on the OER-activity is beneficial to further optimize WES. The current presentation will thus give detailed insights to structural aspects obtained by Raman spectroscopy, small- and wide-angle X-ray scattering which are then combined with electrochemical parameters to deduce structure-activity relationships. T2 - Joint Polish-German Crystallographic Meeting 2020 CY - Wrocław, Poland DA - 24.02.2020 KW - nanostructured KW - electrocatalysis PY - 2020 AN - OPUS4-50664 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baláž, M. A1 - Tešinský, M. A1 - Marquardt, Julien A1 - Škrobian, M. A1 - Daneu, N. A1 - Rajňák, M. A1 - Baláž, P. T1 - Synthesis of copper nanoparticles from refractory sulfides using a semi-industrial mechanochemical approach N2 - The large-scale mechanochemical reduction of binary sulfides chalcocite (Cu2S) and covellite (CuS) by elemental iron was investigated in this work. The reduction of Cu2S was almost complete after 360 min of milling, whereas in the case of CuS, a significant amount of non-reacted elemental iron could still be identified after 480 min. Upon application of more effective laboratory-scale planetary ball milling, it was possible to reach almost complete reduction of CuS. Longer milling leads to the formation of ternary sulfides and oxidation product, namely cuprospinel CuFe2O4. The rate constant calculated from the magnetometry measurements using a diffusion model for Cu2S and CuS reduction by iron in a large-scale mill is 0.056 min−0.5 and 0.037 min−0.5, respectively, whereas for the CuS reduction in a laboratory-scale mill, it is 0.1477 min−1. The nanocrystalline character of the samples was confirmed by TEM and XRD, as the produced Cu exhibited sizes up to 16 nm in all cases. The process can be easily scaled up and thus copper can be obtained much easier from refractory minerals than in traditional metallurgical approaches. KW - Mechanochemistry KW - Copper sulfides KW - Copper nanoparticles KW - Magnetometry KW - Oxidation PY - 2020 DO - https://doi.org/10.1016/j.apt.2019.11.032 VL - 31 IS - 2 SP - 782 EP - 791 PB - Elsevier B.V. AN - OPUS4-50665 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heilmann, Maria A1 - Kulla, Hannes A1 - Prinz, Carsten A1 - Bienert, Ralf A1 - Reinholz, Uwe A1 - de Oliveira Guilherme Buzanich, Ana A1 - Emmerling, Franziska T1 - Advances in Nickel Nanoparticle Synthesis via Oleylamine Route N2 - Nickel nanoparticles are an active research area due to their multiple applications as catalysts in different processes. A variety of preparation techniques have been reported for the synthesis of these nanoparticles, including solvothermal, microwave-assisted, and emulsion techniques. The well-studied solvothermal oleylamine synthesis route comes with the drawback of needing standard air-free techniques and often space-consuming glassware. Here, we present a facile and straightforward synthesis method for size-controlled highly monodisperse nickel nanoparticles avoiding the use of, e.g., Schlenk techniques and space-consuming labware. The nanoparticles produced by this novel synthetic route were investigated using small-angle X-ray scattering, transmission electron microscopy, X-ray diffraction, and X-ray spectroscopy. The nanoparticles were in a size range of 4–16 nm, show high sphericity, no oxidation, and no agglomeration after synthesis. KW - Nanoparticle synthesis KW - Nickel nanoparticles KW - SAXS KW - TEM KW - XAS PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507531 DO - https://doi.org/10.3390/nano10040713 VL - 10 IS - 4 SP - 713 PB - MDPI AN - OPUS4-50753 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heilmann, Maria A1 - Kulla, Hannes A1 - Prinz, Carsten A1 - Bienert, Ralf A1 - Marquardt, Julien A1 - de Oliveira Guilherme Buzanich, Ana A1 - Emmerling, Franziska T1 - Synthesis of Bimetallic Nickel Nanoparticles as Catalysts for the Sabatier Reaction N2 - Nanoparticles (NP) have become important materials for a variety of chemical technologies. The enhance surface-area-to-volume ratio of NPs is very high, making them excellent for use as catalyst, in analytical assays, and for antimicrobial applications. Nickel NPs have exhibited immense potential as important catalyst for the Sabatier reaction, i.e. converting waste to energy via transformation of CO2 into CH4, and could replace the rare earth elements such as Ru, PT, or Rh. In this work we describe the solvothermal synthesis of monometallic and bimetallic nickel nanoparticles. Monodisperse monometallic Ni nanoparticles were synthesized using Oleylamin as solvent and reducing agent. The nanoparticles were investigated using small angle scattering (SAXS), scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDX), showing that the catalytically active sites are accessible. However, Ni has a high propensity to undergo oxidation, and becoming deactivated by coke formation. Hence, we further explore the preparation of bimetallic NPs, where a second metal is added to stabilize the Ni. Bimetallic Cu-Ni NPs were synthesized by simultaneous solvothermal reduction. These bimetallic NPs exhibit excellent catalytic properties are promising candidates to be used as catalysts for efficient energy storage. T2 - Joint Polish-German Crystallographic Meeting CY - Wroclaw, Poland DA - 24.02.2020 KW - Nanoparticles KW - Synthesis KW - Catalysis PY - 2020 AN - OPUS4-51663 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Feiler, Torvid A1 - Bhattacharya, Biswajit A1 - Michalchuk, Adam A1 - Schröder, V. A1 - List-Kratochvil, E. A1 - Emmerling, Franziska T1 - Mechanochemical Syntheses of Isostructural Luminescent Cocrystals of 9-Anthracenecarboxylic Acid with two Dipyridines Coformers N2 - Tuning and controlling the solid-state photophysical properties of organic luminophore are very important to develop next-generation organic luminescent materials. With the aim of discovering new functional luminescent materials, new cocrystals of 9-anthracene carboxylic acid (ACA) were prepared with two different dipyridine coformers: 1,2-bis(4-pyridyl)ethylene and 1,2-bis(4-pyridyl)ethane. The cocrystals were successfully obtained by both mechanochemical approaches and conventional solvent crystallization. The newly obtained crystalline solids were characterized thoroughly using a combination of single crystal X-ray diffraction, powder X-ray diffraction, Fourier-transform infrared spectroscopy, differential thermal analysis, and thermogravimetric analysis. Structural analysis revealed that the cocrystals are isostructural, exhibiting two-fold interpenetrated hydrogen bonded networks. While the O–H···N hydrogen bonds adopts a primary role in the stabilization of the cocrystal phases, the C–H···O hydrogen bonding interactions appear to play a significant role in guiding the three-dimensional assembly. Both π···π and C–H···π interactions assist in stabilizing the interpenetrated structure. The photoluminescence properties of both the starting materials and cocrystals were examined in their solid states. All the cocrystals display tunable photophysical properties as compared to pure ACA. Density functional theory simulations suggest that the modified optical properties result from charge transfers between the ACA and coformer molecules in each case. This study demonstrates the potential of crystal engineering to design solid-state luminescence switching materials through cocrystallization. KW - Cocrystal KW - Mechanochemical synthesis KW - Luminescence KW - X-ray diffraction KW - DFT calculation PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518226 DO - https://doi.org/10.3390/cryst10100889 VL - 10 IS - 10 SP - 889 PB - MDPI AN - OPUS4-51822 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kunkel, B. A1 - Kabelitz, Anke A1 - de Oliveira Guilherme Buzanich, Ana A1 - Wohlrab, S. T1 - Increasing the Efficiency of Optimized V-SBA-15 Catalysts in the Selective Oxidation of Methane to Formaldehyde by Artificial Neural Network Modelling N2 - The present study investigates the possibility of improving the selective oxidation of methane to formaldehyde over V-SBA-15 catalysts in two different ways. In a classical approach of catalyst optimization, the in situ synthesis of V-SBA-15 catalysts was optimized with regard to the applied pH value. Among the set of catalysts synthesized, a higher amount of incorporated vanadium, a higher content of polymeric VOx species as well as a less ordered structure of the support material were observed by increasing the pH values from 2.0 to 3.0. An optimum in performance during the selective oxidation of methane to formaldehyde with respect to activity and selectivity was found over V-SBA-15 prepared at a pH value of 2.5. With this knowledge, we have now evaluated the possibilities of reaction control using this catalyst. Specifically, artificial neural network modelling was applied after the collection of 232 training samples for obtaining insight into the influence of different reaction parameters (temperature; gas hourly space velocity (GHSV); and concentration of O2, N2 and H2O) onto methane conversion and selectivity towards formaldehyde. This optimization of reaction conditions resulted in an outstanding high space-time yield of 13.6 kgCH2O∙kgcat∙h−1 KW - Artificial neural network modelling KW - Selective oxidation KW - Molecular VOx catalysts KW - Formaldehyde PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517420 DO - https://doi.org/10.3390/catal10121411 VL - 10 IS - 12 SP - 1411 PB - MDPI AN - OPUS4-51742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Surov, A. A1 - Vasilev, N. A1 - Voronin, A. A1 - Churakov, A. A1 - Emmerling, Franziska A1 - Perlovich, G. T1 - Ciprofloxacin salts with benzoic acid derivatives: structural aspects, solid-state properties and solubility performance N2 - n this work, three new pharmaceutical hydrated salts of ciprofloxacin with selected derivatives of benzoic acid, namely 4-hydroxybenzoic acid, 4-aminobenzoic acid and gallic acid, were obtained and systematically investigated by several solid-state analytical techniques. In situ Raman spectroscopy was applied to elucidate the alternative pathways of the solid forms' formation under mechanochemical conditions. Crystal structure analysis and a CSD survey allowed us to establish a distinct supramolecular motif formed by infinite columnar stacks of ciprofloxacin dimers arranged in the “head-to-tail” manner. An alternative “head-to-head” packing arrangement was only observed in the crystal of the hydrated ciprofloxacin salt with 4-aminobenzoic acid. In addition, the pH-solubility behavior of the solid forms was thoroughly investigated. Furthermore, a distinct structure–property relationship between the specific features of the supramolecular organization of the hydrated salts and their solubility was observed and discussed. KW - Mechanochemistry KW - XRD PY - 2020 DO - https://doi.org/10.1039/D0CE00514B VL - 22 IS - 25 SP - 4238 EP - 4249 AN - OPUS4-51818 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Opitz, P. A1 - Asta, M. A1 - Fernandez-Martinez, A. A1 - Panthöfer, M. A1 - Kabelitz, Anke A1 - Emmerling, Franziska A1 - Mondeshki, M. A1 - Tremel, W. T1 - Monitoring a Mechanochemical Syntheses of Isostructural Luminescent Cocrystals of 9-Anthracenecarboxylic Acid with two Dipyridines Coformers N2 - Amorphous calcium carbonate (ACC) is an important precursor in the biomineralization of crystalline CaCO3. In nature, it serves as a storage material or as a permanent structural element, whose lifetime is regulated by an organic matrix. The relevance of ACC in materials science is primarily related to our understanding of CaCO3 crystallization pathways and CaCO3/(bio)polymer nanocomposites. ACC can be synthesized by liquid–liquid phase separation, and it is typically stabilized with macromolecules. We have prepared ACC by milling calcite in a planetary ball mill. Phosphate “impurities” were added in the form of monetite (CaHPO4) to substitute the carbonate anions, thereby stabilizing ACC by substitutional disorder. The phosphate anions do not simply replace the carbonate anions. They undergo shear-driven acid/base and condensation reactions, where stoichiometric (10%) phosphate contents are required for the amorphization to be complete. The phosphate anions generate a strained network that hinders ACC recrystallization kinetically. The amorphization reaction and the structure of BM-ACC were studied by quantitative Fourier transform infrared spectroscopy and solid state 31P, 13C, and 1H magic angle spinning nuclear magnetic resonance spectroscopy, which are highly sensitive to symmetry changes of the local environment. In the first—and fast—reaction step, the CO32– anions are protonated by the HPO42– groups. The formation of unprecedented hydrogen carbonate (HCO3–) and orthophosphate anions appears to be the driving force of the reaction, because the phosphate group has a higher Coulomb energy and the tetrahedral PO43– unit can fill space more efficiently. In a competing second—and slow—reaction step, pyrophosphate anions are formed in a condensation reaction. No pyrophosphates are formed at higher carbonate contents. High strain leads to such a large energy barrier that any reaction is suppressed. Our findings aid in the understanding of the mechanochemical amorphization of calcium carbonate and emphasize the effect of impurities for the stabilization of the amorphous phases in general. Our approach allowed the synthesis of new amorphous alkaline earth defect variants containing the unique HCO3– anion. Our approach outlines a general strategy to obtain new amorphous solids for a variety of carbonate/phosphate systems that offer promise as biomaterials for bone regeneration. KW - Crystallization KW - Mechanochemistry KW - PDF PY - 2020 DO - https://doi.org/10.1021/acs.cgd.0c00912 VL - 20 IS - 10 SP - 6831 EP - 6846 PB - American Chemical Society AN - OPUS4-51819 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Oliveira Guilherme Buzanich, Ana A1 - Kulow, Anicó A1 - Kabelitz, Anke A1 - Grunewald, C. A1 - Seidel, R. A1 - Chapartegui-Arias, Ander A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Emmerling, Franziska A1 - Beyer, S. T1 - Observation of early ZIF-8 crystallization stages with X-ray absorption spectroscopy N2 - The present study investigates early stages of ZIF-8 crystallization up to 5 minutes post mixing of precursor solutions. Dispersive X-ray Absorption Spectroscopy (DXAS) provides a refined understanding of the evolution of the coordination environment during ZIF-8 crystallization. Linear Combination Fiting (LCF) suggests tetrakis(1-methylimidazole)zinc2+ to be a suitable and stable mononuclear structure analogue for some early stage ZIF-8 intermediates. Our results pave the way for more detailed studies on physico-chemical aspects of ZIF-8 crystallization to better control tailoring ZIF-8 materials for specific applications. KW - In-situ KW - XANES KW - ZIF-8 KW - Crystallization PY - 2020 DO - https://doi.org/10.1039/D0SM01356K SN - 1744-6848 VL - 17 IS - 2 SP - 331 EP - 334 PB - Royal Scociety of Chemistry AN - OPUS4-51723 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Olivera, Paulo A1 - Michalchuk, Adam A1 - Marquardt, Julien A1 - Feiler, Torvid A1 - Prinz, Carsten A1 - Torresi, R. A1 - Camargo, P. A1 - Emmerling, Franziska T1 - Investigating the role of reducing agents on mechanosynthesis of Au nanoparticles N2 - Control over the bottom up synthesis of metal nanoparticles (NP) depends on many experimental factors, including the choice of stabilising and reducing agents. By selectively manipulating these species, it is possible to control NP characteristics through solution-phase synthesis strategies. It is not known, however, whether NPs produced from mechanochemical syntheses are governed by the same rules. Using the Au NPs mechanosynthesis as a model system, we investigate how a series of common reducing agents affect both the reduction kinetics and size of Au NPs. It is shown that the relative effects of reducing agents on mechanochemical NP synthesis differ significantly from their role in analogous solution-phase reactions. Hence, strategies developed for control over NP growth in solution are not directly transferrable to environmentally benign mechanochemical approaches. This work demonstrates a clear need for dedicated, systematic studies on NP mechanosynthesis. KW - Mechanochemistry KW - Metal nanoparicels PY - 2020 DO - https://doi.org/10.1039/d0ce00826e VL - 22 IS - 38 SP - 6261 EP - 6267 PB - Royal Society of Chemistry AN - OPUS4-51757 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Olivera, Paulo A1 - Michalchuk, Adam A1 - de Oliveira Guilherme Buzanich, Ana A1 - Bienert, Ralf A1 - Torresi, R. A1 - Camargo, P. A1 - Emmerling, Franziska T1 - Tandem X-ray absorption spectroscopy and scattering for in situ time-resolved monitoring of gold nanoparticle mechanosynthesis N2 - Current time-resolved in situ approaches limit the scope of mechanochemical investigations possible. Here we develop a new, general approach to simultaneously follow the evolution of bulk atomic and electronic structure during a mechanochemical synthesis. This is achieved by coupling two complementary synchrotron-based X-ray methods: X-ray absorption spectroscopy (XAS) and X-ray diffraction. We apply this method to investigate the bottom-up mechanosynthesis of technologically important Au micro and nanoparticles in the presence of three different reducing agents, hydroquinone, sodium citrate, and NaBH4. Moreover, we show how XAS offers new insight into the early stage generation of growth species (e.g. monomers and clusters), which lead to the subsequent formation of nanoparticles. These processes are beyond the detection capabilities of diffraction methods. This combined X-ray approach paves the way to new directions in mechanochemical research of advanced electronic materials. KW - Mechanochemistry KW - XANES KW - X-ray diffraction KW - Nano particles PY - 2020 DO - https://doi.org/10.1039/d0cc03862h SN - 1364-548X VL - 56 SP - 10329 EP - 10332 PB - Royal Society of Chemistry AN - OPUS4-51760 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Maack, Stefan A1 - Bertovic, Marija A1 - Radtke, Martin A1 - et al., ED - Wahlster, W. ED - Winterhalter, C. T1 - Deutsche Normungsroadmap künstliche Intelligenz N2 - Rund ein Jahr haben DIN und DKE in einem gemeinsamen Projekt mit dem Bundesministerium für Wirtschaft und Energie und zusammen mit ca. 300 Fachleuten aus Wirtschaft, Wissenschaft, öffentlicher Hand und Zivilgesellschaft an der Normungsroadmap Künstliche Intelligenz gearbeitet. Eine hochrangige Steuerungsgruppe unter dem Vorsitz von Prof. Wolfgang Wahlster hat die Erarbeitung koordiniert und begleitet. Ziel der Roadmap ist die frühzeitige Entwicklung eines Handlungsrahmens für die Normung und Standardisierung, der die internationale Wettbewerbsfähigkeit der deutschen Wirtschaft unterstützt und europäische Wertmaßstäbe auf die internationale Ebene hebt. KW - Künstliche Intelligenz KW - Normung KW - Roadmap PY - 2020 UR - https://www.din.de/resource/blob/772438/ecb20518d982843c3f8b0cd106f13881/normungsroadmap-ki-data.pdf VL - 2020 SP - 1 EP - 232 PB - Deutsches Institut für Normung (DIN) CY - Berlin ET - 1. AN - OPUS4-51733 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epping, Ruben A1 - Falkenhagen, Jana A1 - Panne, Ulrich A1 - Hiller, W. A1 - Gruendling, T. A1 - Staal, B. A1 - Lang, C. A1 - Lamprou, A. T1 - Simultaneous characterization of poly(acrylic acid) andpolysaccharide polymers and copolymers N2 - Copolymer products that result from grafting acrylic acid and other hydrophilicmonomers onto polysaccharides have recently gained significant interest in researchand industry. Originating from renewable sources, these biodegradable, low toxicity,and polar copolymer products exhibit potential to replace polymers from fossil sourcesin several applications and industries. The methods usually employed to character-ize these copolymers are, however, quite limited, especially for the measurement ofbulk properties. With more sophisticated applications, for example, in pharmaceu-tics requiring a more detailed analysis of the chemical structure, we describe a newapproach for this kind of complex polymers. Our approach utilizes chromatographyin combination with several detection methods to separate and characterize reactionproducts of the copolymerization of acrylic acid and chemically hydrolyzed starch.These samples consisted of a mixture of homopolymer poly (acrylic acid), homopoly-mer hydrolyzed starch, and – in a lower amount – the formed copolymers. Several chro-matographic methods exist that are capable of characterizing either poly (acrylic acid)or hydrolyzed starch. In contrast, our approach offers simultaneous characterization ofboth polymers. The combination of LC and UV/RI offered insight into the compositionand copolymer content of the samples. Size exclusion chromatography experimentsrevealed the molar mass distribution of homopolymers and copolymers. FTIR inves-tigations confirmed the formation of copolymers while ESI-MS gave more details onthe end groups of hydrolyzed starches and poly (acrylic acids). Evidence of copolymerstructures was obtained through NMR measurements. Finally, two-dimensional chro-matography led to the separation of the copolymers from both homopolymers as wellas the additional separation of sodium clusters. The methods described in this work area powerful toolset to characterize copolymerization products of hydrolyzed starch andpoly(acrylic acid). Together, our approach successfully correlates the physicochemicalproperties of such complex mixtures with their actual composition. KW - 2D chromatography KW - LC-MS KW - SEC KW - Renewable copolymers KW - Grafting PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508873 DO - https://doi.org/10.1002/ansa.202000044 SP - 1 EP - 12 PB - Wiley-VCH Verlag-GmbH&Co. KGaA CY - Weinheim AN - OPUS4-50887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lutz, C. A1 - Hampel, S. A1 - Ke, X. A1 - Beuermann, S. A1 - Turek, T. A1 - Kunz, U. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Fittschen, U. T1 - Evidence for redox reactions during vanadium crossover inside the nanoscopic water-body of Nafion 117 using X-ray absorption near edge structure spectroscopy N2 - A major source of capacity fade of the common vanadium redox flow battery (VRFB) is the vanadium ion transport through the separator. However, different transport models disagree significantly in the diffusion coefficient for the different V species and the influence of different transport mechanisms. The underlying hypothesis of this work is that reactions inside the membrane are partly responsible for these discrepancies. Accordingly, it was investigated if redox reactions inside the nanoscopic water body of Nafion 117 can occur. X-ray absorption near edge structure spectroscopy (XANES) was used to distinguish between the different V species inside hydrated Nafion 117 and novel PVDF-based membranes. It was validated that the speciation of vanadium can be performed using the pre-edge peak energy and intensity. The experiments were performed as follows: strips of the membrane were exposed from one site to a V3+ solution (green) and from the other site to a VO2+ solution (yellow). The ions could diffuse into the membrane from both sides. A change of color of the membrane strip was observed. The blue color in the middle of the strip indicated that VO2+ was formed where V3+ and VO2+ got in contact. Using XANES this reaction inside Nafion was proven. KW - PVDF-Based membrane KW - VRFB KW - Vanadium speciation KW - XANES KW - Nafion 117 PY - 2020 DO - https://doi.org/10.1016/j.jpowsour.2020.229176 VL - 483 SP - 229176 PB - Elsevier B.V. AN - OPUS4-51719 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - You, Zengchao A1 - Nirmalananthan-Budau, Nithiya A1 - Resch-Genger, Ute A1 - Panne, Ulrich A1 - Weidner, Steffen T1 - Separation of polystyrene nanoparticles bearing different carboxyl group densities and functional groups quantification with capillary electrophoresis and asymmetrical flow field flow fractionation N2 - Two sets of polystyrene nanoparticles (PSNPs) with comparable core sizes but different carboxyl group densities were made and separated using asymmetric flow field flow fractionation (AF4), capillary electrophoresis (CE), and the off-line hyphenation of both methods. Our results revealed the significant potential of two-dimensional off-line AF4-CE hyphenation to improve the separation and demonstrated for the first time, the applicability of CE to determine the functional group density of nanoparticles (NPs). Compared to the result acquired with conductometric titration, the result obtained with synthesized 100 nm sized PSNPs revealed only a slight deviation of 1.7%. Commercial 100 nm sized PSNPs yielded a deviation of 4.6 %. For 60 nm sized PSNPs, a larger deviation of 10.6 % between both methods was observed, which is attributed to the lower separation resolution. KW - Nanoparticle KW - A4F KW - Capillary electrophoresis KW - Carboxyl group PY - 2020 DO - https://doi.org/10.1016/j.chroma.2020.461392 VL - 1626 SP - 461392 PB - Elsevier B.V. AN - OPUS4-51080 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xue, Boyang A1 - You, Yi A1 - Gornushkin, Igor B. A1 - Zheng, R. A1 - Riedel, Jens T1 - High-throughput underwater elemental analysis by μJ-laser-induced breakdown spectroscopy at kHz repetition rates: part I, ultrasound-enhanced optical emission spectroscopy towards application perspectives N2 - In recent years, laser-induced breakdown spectroscopy (LIBS) has gained significant attention as a means for simple elemental analyses. The suitability of LIBS for contactless analysis allows it to be a perfect candidate for underwater applications. While the majority of LIBS systems still rely upon sub-kHz pulsed lasers, this contribution introduces 10s-kHz low pulse-energy lasers into underwater LIBS to improve the throughput and statistical validity. Interestingly, the spectral component significantly changed above a critical laser repetition-rate threshold. Spectral lines of atomic hydrogen and oxygen stemming from water become visible beyond a ∼10 kHz repetition rate. This observation suggests a different plasma dynamic compared to low repetition rates. When the pulse-to-pulse interval becomes sufficiently short, a cumulative effect begins to be significant. Apparently, the new phenomena occur on a timescale corresponding to a threshold rate of ∼10 kHz, i.e. ∼100 μs. Analytically, the high repetition rates result in improved statistical validity and throughput. More plasma events per unit time allowed the use of low efficiency Echelle spectrometers without compromising on the analytical performance. Meanwhile, the presence of H I and O I out of the water (as the matrix) also offers internal standardization in underwater elemental analysis. Since the laser fluence was on the lower edge of the plasma threshold, an additional ultrasound source was introduced to induce external perturbation, which significantly improved the plasma formation stability. A huge advantage of LIBS is the possibility of detecting almost all elements within a sample simultaneously. Throughout the periodic table, chlorine is one of the most challenging elements. Consequently, Ca2+ and Na+ were used as samples to demonstrate the capability of this high repetition-rate LIBS platform. As an ambitious benchmark for our system, chlorine detection in water was also discussed. KW - High repetition rate KW - Laser-induced breakdown spectroscopy PY - 2020 DO - https://doi.org/10.1039/D0JA00290A VL - 35 IS - 12 SP - 2901 EP - 2911 PB - The Royal Society of Chemistry AN - OPUS4-51564 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xue, Boyang A1 - You, Yi A1 - Riedel, Jens T1 - High-throughput underwater elemental analysis by μJ-laser-induced breakdown spectroscopy at a kHz repetition rate: part II, understanding the high repetition-rate from a fundamental perspective N2 - The technological advances in lasers enabled the wide application of laser-induced breakdown spectroscopy (LIBS) as a powerful analytical means for elemental analyses. Rather than commonly used lasers that operate at several to several-tens of Hz, the high repetition rate ones that operate at tens of kHz showed superior analytical advantages while implying unique excitation pathways. Specifically, the production of excited atomic hydrogen and oxygen, which can serve as internal standards, is quite different from that in commonly reported double-pulse LIBS. In this part of the work, it was found that the atomic emitters stemming from water are not related to cavitation bubbles. Moreover, the emitter productions of dissolved species, e.g., Na+, and water-related species, e.g., H-α, are two distinctive mechanisms. Towards analytical applications of the high repetition-rate system, the fundamental investigation can provide important guidelines to address real-life challenges. In this part of the work, the high repetition-rate regime of operation is explored from a more kinetic perspective. KW - High repetition rate KW - Laser-induced breakdown spectroscopy PY - 2020 DO - https://doi.org/10.1039/D0JA00291G VL - 35 IS - 12 SP - 2912 EP - 2919 PB - Royal Society of Chemistry AN - OPUS4-51565 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Epping, Ruben T1 - Microstructure characterization of oligomers by analysis of UPLC / ESI-TOF-MS reconstructed ion chromatograms N2 - It is a well-known story that copolymers beside their molar mass distribution (MMD) can exhibit a functionality type distribution (FTD), a copolymer composition distribution (CCD), a monomer sequence distribution (MSD) and additionally different topologies within one sample. Small, often isobaric heterogeneities in topology or microstructure can usually not be simply separated chromatographically or distinguished by any common detector. Nowadays a wide range of different analytical separation techniques and multi-detection possibilities are available. The challenge consists in a clever combination of these techniques with a specific approach of data analysis. In this presentation different liquid chromatographic separation modes were combined with Electrospray Time-of-Flight mass spectrometry. The online coupling allows the analysis of reconstructed ion chromatograms (RIC) of each degree of polymerization. While a complete separation often cannot be achieved, the derived retention times and peak widths lead to information on the existence and dispersity of heterogeneities in microstructure or topology, that are otherwise inaccessible This method is suitable to detect small differences in e. g. branching, topology, monomer sequence or tacticity and could potentially be used in production control of oligomeric products or other routinely done analyses to quickly indicate deviations from set parameters. Based on a variety of examples e.g. the topology elucidation of branched EO-PO copolymers, the possibilities and limitations of this approach were demonstrated. T2 - Analyticon 2020 CY - Online meeting DA - 05.11.2020 KW - Microstructure KW - Copolymer KW - LC-MS PY - 2020 AN - OPUS4-51540 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kulow, Anicó A1 - de Oliveira Guilherme Buzanich, Ana A1 - Reinholz, Uwe A1 - Emmerling, Franziska A1 - Hampel, S. A1 - Fittschen, U.E.A. A1 - Streli, C. A1 - Radtke, Martin T1 - Comparison of three reconstruction methods based on deconvolution, iterative algorithm and neural network for X-ray fluorescence imaging with coded apertures N2 - X-ray imaging methods are used in many fields of research, as they allow a non-destructive Investigation of the elemental content of various samples. As for every imaging method, for X-ray imaging the optics are of crucial importance. However, these optics can be very expensive and laborious to build, as the requirements on surface roughness and precision are extremely high. Angles of reflection and refraction are often in the range of a few mrad, making a compact design hard to achieve. In this work we present a possibility to simplify X-ray imaging. We have adapted the coded aperture method, a high energy radiation imaging method that has its origins in astrophysics, to full field X-ray fluorescence imaging. In coded aperture imaging, an object is projected through a known mask, the coded aperture, onto an area sensitive detector. The resulting image consists of overlapping projections of the object and a reconstruction step is necessary to obtain the information from the recorded image. We recorded fluorescence images of different samples with an energy-dispersive 2D detector (pnCCD) and investigated different reconstruction methods. With a small coded aperture with 12 holes we could significantly increase the count rate compared to measurements with a straight polycapillary optic. We show that the reconstruction of two different samples is possible with a deconvolution approach, an iterative algorithm and a neural network. These results demonstrate that X-ray fluorescence imaging with coded apertures has the potential to deliver good results without scanning and with an improved count rate, so that measurement times can be shortened compared to established methods. KW - X-ray fluorescence imaging KW - Coded apertures KW - Imaging KW - Elemental mapping KW - Image reconstruction PY - 2020 DO - https://doi.org/10.1039/d0ja00146e VL - 35 IS - 7 SP - 1423 EP - 1434 PB - Royal Society of Chemistry CY - United Kingdom AN - OPUS4-51518 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Medeiros, V.L. A1 - Goulart de Araujo, L. A1 - Ratero, D.R. A1 - Paula, A.S. A1 - Ferreira Molina, E. A1 - Jaeger, Christian A1 - Takehiro Marumo, J. T1 - Synthesis and physicochemical characterization of a novel adsorbent based on yttrium silicate: A potential material for removal of lead and cadmium from aqueous media N2 - A new metallosilicate based on yttrium was synthesized and characterized by XRD, FT-IR, 29Si MAS-NMR, and 89Y MAS-NMR. The mixed framework of the material was confirmed by the detection of distinct chemical shift groups using 29Si MAS-NMR (at -82 to -87 ppm, -91 to -94 ppm, -96 to -102 ppm, and -105 to -108 ppm), as well as four distinct chemical shifts in the 89Y MAS-NMR spectrum (at -89, -142, -160, and -220 ppm). Adsorption and kinetic analyses indicated the potential of the new material for the removal of lead and cadmium from aqueous media. The adsorption results for lead indicated that dynamic equilibrium was reached after five hours, with total lead removal of around 94 %, while for cadmium it was reached in the first hour, with total Cadmium removal of around 74 %. The adsorptions of lead and cadmium were modeled using pseudo-first order (PFO) and pseudo-second order (PSO) kinetic models. Although both models provided high R2 values (0.9903 and 0.9980, respectively), the PSO model presented a much lower χ2 red value (4.41×10−4), compared to the PFO model (2.12×10−3), which indicated that the rate-limiting step was probably due to the chemisorption of lead from the solution onto the yttrium-based metallosilicate. KW - Yttrium silicates KW - 29Si KW - 89Y MAS-NMR KW - Adsorption KW - Chemisorption KW - Cadmium and lead remediation PY - 2020 DO - https://doi.org/10.1016/j.jece.2020.103922 VL - 8 SP - 103922 PB - Elsevier Ltd. AN - OPUS4-51292 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schiffmann, J. A1 - Emmerling, Franziska A1 - Martins, Ines A1 - Van Wüllen, L. T1 - In-situ reaction monitoring of a mechanochemical ball mill reaction with solid state NMR N2 - We present an approach towards the in situ solid state NMR monitoring of mechanochemical reactions in a ball mill. A miniaturized vibration ball mill is integrated into the measuring coil of a home-built solid state NMR probe, allowing for static solid state NMR measurements during the mechanochemical reaction within the vessel. The setup allows to quantitatively follow the product evolution of a prototypical mechanochemical reaction, the formation of zinc phenylphosphonate from zinc acetate and phenylphosphonic acid. MAS NMR investigations on the final reaction mixture confirmed a reaction yield of 89% in a typical example. Thus, NMR spectroscopy may in the future provide complementary information about reaction mechanisms of mechanochemical reactions and team up with other analytical methods which have been employed to follow reactions in situ, such as Raman spectroscopy or X-ray diffraction. KW - Mechanochemistry KW - Solid state NMR KW - NMR probe Development PY - 2020 DO - https://doi.org/10.1016/j.ssnmr.2020.101687 VL - 109 SP - 101687 PB - Elsevier Inc. AN - OPUS4-51283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lumpe, H. A1 - Menke, Annika A1 - Haisch, C. A1 - Mayer, P. A1 - Kabelitz, Anke A1 - Yusenko, Kirill A1 - de Oliveira Guilherme Buzanich, Ana A1 - Block, T. A1 - Pöttgen, R. A1 - Emmerling, Franziska A1 - Daumann, L. T1 - The Earlier the Better: Structural Analysis and Separation of Lanthanides with Pyrroloquinoline Quinone N2 - Lanthanides (Ln) are critical raw materials, however, their mining and purification have a considerable negative environmental impact and sustainable recycling and separation strategies for these elements are needed. In this study, the precipitation and solubility behavior of Ln complexes with pyrroloquinoline quinone (PQQ), the cofactor of recently discovered lanthanide (Ln) dependent methanol dehydrogenase (MDH) enzymes, is presented. In this context, the molecular structure of a biorelevant europium PQQ complex was for the first time elucidated outside a protein environment. The complex crystallizes as an inversion symmetric dimer, Eu2PQQ2, with binding of Eu in the biologically relevant pocket of PQQ. LnPQQ and Ln1Ln2PQQ complexes were characterized by using inductively coupled plasma mass spectrometry (ICP‐MS), infrared (IR) spectroscopy, 151Eu‐Mössbauer spectroscopy, X‐ray total scattering, and extended X‐ray absorption fine structure (EXAFS). It is shown that a natural enzymatic cofactor is capable to achieve separation by precipitation of the notoriously similar, and thus difficult to separate, lanthanides to some extent. KW - PQQ KW - Lanthanoide KW - Coordination chemistry KW - Rare earth elements separations PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512707 DO - https://doi.org/10.1002/chem.202002653 VL - 26 IS - 44 SP - 10133 EP - 10139 AN - OPUS4-51270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baumann, Maria A1 - Falkenhagen, Jana A1 - Weidner, Steffen A1 - Wold, C. A1 - Uliyanchenko, E. T1 - Characterization of copolymers of polycarbonate and polydimethylsiloxane by 2D chromatographic separation, MALDI-TOF mass spectrometry, and FTIR spectroscopy N2 - The structure and composition of polycarbonate polydimethylsiloxane copolymer (PC-co-PDMS) was investigated by applying various analytical approaches including chromatographic separation methods, spectrometric, and spectroscopic detection techniques. In particular, size exclusion chromatography (SEC) and liquid adsorption chromatography operating at different conditions (e.g. using gradient solvent systems) were used to achieve separations according to molar mass and functionality distribution. The coupling of both techniques resulted in fingerprint two-dimensional plots, which could be used to easily compare different copolymer batches. Matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry was applied for structural investigations. The different ionization behavior of both comonomers, however, strongly limited the applicability of this technique. In contrast to that, Fourier-transform Infrared (FTIR) spectroscopy could be used to quantify the amount of PDMS in the copolymer at different points in the chromatogram. The resulting methodology was capable of distinguishing PC-co-PDMS copolymer from PC homopolymer chains present in the material. KW - FTIR KW - Liquid chromatography KW - Mass spectrometry KW - Gradient elution KW - Polycarbonate-co-dimethylsiloxane copolymer PY - 2020 DO - https://doi.org/10.1080/1023666X.2020.1820170 VL - 25 IS - 7 SP - 1 EP - 12 PB - Taylor & Francis AN - OPUS4-51369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Usmani, Shirin M. A1 - Plarre, Rüdiger A1 - Hübert, Thomas A1 - Kemnitz, E. ED - Richter, K. ED - Van de Kulien, J.-W. T1 - Termite resistance of pine wood treated with nano metal fluorides N2 - Fluorides are well-known as wood preservatives. One of the limitations of fluoride-based wood preservatives is their high leachability. Alternative to current fluoride salts such as NaF used in wood protection are low water-soluble fluorides. However, impregnation of low water-soluble fluorides into wood poses a challenge. To address this challenge, low water-soluble fluorides like calcium fluoride (CaF2) and magnesium fluoride (MgF2) were synthesized as nanoparticles via the fluorolytic sol−gel synthesis and then impregnated into wood specimens. In this study, the toxicity of nano metal fluorides was assessed by termite mortality, mass loss and visual analysis of treated specimens after eight weeks of exposure to termites, Coptotermes formosanus. Nano metal fluorides with sol concentrations of 0.5 M and higher were found to be effective against termites resulting in 100% termite mortality and significantly inhibited termite feeding. Among the formulations tested, the least damage was found for specimens treated with combinations of CaF2 and MgF2 with an average mass loss less than 1% and visual rating of “1”. These results demonstrate the efficacy of low water-soluble nano metal fluorides to protect wood from termite attack. KW - Holzschutzmittel KW - Nanoparticles KW - Fluorides KW - Termites PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514325 DO - https://doi.org/10.1007/s00107-020-01522-z VL - 78 SP - 493 EP - 499 PB - Springer CY - Berlin AN - OPUS4-51432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen T1 - Reply to the comment on “synthesis of cyclic polymers and flaws of the Jacobson-Stockmayer theory” by R. Szymanski N2 - In a recent publication the authors have presented theoretical and experimental results indicating that the Jacobson–Stockmayer (JS) theory does not provide a correct description of reversible polycondensations for all polymers and for high conversions (e.g. polycondensation in bulk). In this context reversibility means that all condensation step whether resulting in chain growth or in cyclization are reversible and thus, part of an equilibrium. The first two sections of that paper were focused on the demonstration that small, and above all, large cycles can be formed by end-to-end (ete) cyclization in reversible like in irreversible polycondensations. A significant contribution of ete-cyclization to the course of reversible polycondensations was denied by J + S apparently as a contribution to Florýs dogma, that the end groups of long polymer chains will never meet. KW - Polylactide KW - MALDI-TOF MS KW - Jacobsen-Stockmayer theory PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513985 DO - https://doi.org/10.1039/D0PY01118E VL - 11 IS - 38 SP - 6226 EP - 6228 PB - Royal Society of Chemistry AN - OPUS4-51398 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abram, Sarah-Luise A1 - Mrkwitschka, Paul A1 - Prinz, Carsten A1 - Rühle, Bastian A1 - Kuchenbecker, Petra A1 - Hodoroaba, Vasile-Dan A1 - Resch-Genger, Ute T1 - Monodisperse iron oxide nanoparticles as reference material candidate for particle size measurements N2 - In order to utilize and rationally design materials at the nanoscale the reliable characterization of their physico-chemical properties is highly important, especially with respect to the assessment of their environmental or biological impact. Furthermore, the European Commission’s REACH Regulations require the registration of nanomaterials traded in quantities of at least 1 ton. Powders or dispersions where 50% (number distribution) of the constituent particles have sizes ≤ 100 nm in at least one dimension are defined as nanomaterials. This creates a need for industrial manufacturers and research or analytical service facilities to reliably characterize potential nanomaterials. Currently, BAM is developing reference nanoparticles, which shall expand the scarce list of worldwide available nano reference materials certified for particle size distribution and will also target other key parameters like shape, structure, porosity or functional properties. In this respect, materials like iron oxide or titanium dioxide are considered as candidates to complement the already available silica, Au, Ag, and polystyrene reference nanoparticles. The thermal decomposition of iron oleate precursors in high boiling organic solvents can provide large quantities of iron oxide nanoparticles that can be varied in size and shape.[1, 2] The presence of oleic acid or other hydrophobic ligands as capping agents ensures stable dispersion in nonpolar solvents. Such monodisperse, spherical particles were synthesized at BAM and pre-characterized by electron microscopy (TEM, SEM including the transmission mode STEM-in-SEM) and dynamic light scattering comparing cumulants analysis and frequency power spectrum. 1. REACH regulations and nanosafety concerns create a strong need for nano reference materials with diverse properties. 2. Iron oxide nanoparticles are under development as new candidate reference material at BAM. 3. Narrow particle size distribution confirmed by light scattering and electron microscopy. T2 - Nanosafety 2020 CY - Online meeting DA - 05.10.2020 KW - Iron oxide nanoparticles KW - Reference material KW - Particle size KW - Electron microscopy KW - Nanoplattform PY - 2020 AN - OPUS4-52774 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Song, L. A1 - You, Yi A1 - Perdomo, R. A1 - Evans-Nguyen, T. T1 - Inexpensive Ultrasonic Nebulization Coupled with Direct Current Corona Discharge Ionization Mass Spectrometry for Liquid Samples and Its Fundamental Investigations N2 - The concept of direct mass-spectrometric analysis, especially exploited by ambient desorption/ionization (ADI) methods, provides numerous means for convenient sample analysis. While many simple and versatile ionization sources have been developed, challenges lay in achieving efficient sample introduction. In previous work, a sample introduction method employing direct current corona discharge (CD) coupled to a surface acoustic wave nebulization (SAWN) device enhanced sampling performance for both polar and nonpolar analytes by up to 4 orders of magnitude. In fact, the SAWN-CD method generated a multiply charged peptide ion signal comparable to that of conventional ESI. Unfortunately, the high cost of the SAWN devices themselves limits their accessibility. Herein, we report on an analogous implementation of CD with an inexpensive ultrasonic nebulizer (USN) on the basis of a commercial room humidifier demonstrating equivalent exemplary performance. We subsequently compare the two methods of SAWN-CD and USN-CD in a screening application of milk for the detection of two antibiotic drugs, ciprofloxacin and ampicillin. Finally, we further investigate the relative softness of these CD-coupled acoustic nebulization methods in comparison to that of ESI using a survival yield study of the thermometer ion nitrobenzylpyridinium. KW - Rapid Analysis KW - Ultrasonic Nebulization KW - Corona Discharge PY - 2020 DO - https://doi.org/10.1021/acs.analchem.0c00524 VL - 92 IS - 16 SP - 11072 PB - ACS Publication AN - OPUS4-51225 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stawski, Tomasz T1 - Scattering is a powerful tool to follow nucleation and growth of minerals from solutions N2 - In recent years, we have come to appreciate the astounding intricacy of the processes leading to the formation of minerals from ions in aqueous solutions. The original, and rather naive, ‘textbook’ image of these phenomena, stemming from the adaptation of classical nucleation and growth theories, has increased in complexity due to the discovery of a variety of precursor and intermediate species. These include solute clusters (e.g. prenucleation clusters, PNCs), liquid(-like) phases, as well as amorphous and nanocrystalline solids etc.. Does it, however, mean that all the minerals grow through intermediate phases, following a non-classical pathway? In general, the precursor or intermediate species constitute different, often short-lived, points along the pathway from dissolved ions to the final solids (typically crystals in this context). In this regard synchrotron-based scattering (SAXS/WAXS/total scattering) appears to be the perfect tool to follow in situ and in a time-resolved manner the crystallization pathway because of the temporal and spatial length scales that can be directly accessed with these techniques. In this presentation we show how we used scattering to probe the crystallisation mechanisms of calcium sulfate, This system contains minerals that are widespread in diverse natural environments, but they are also important in various industrial settings. Our data demonstrate that calcium sulfate precipitation involves formation and aggregation of sub-3 nm anisotropic primary species. The actual crystallisation and formation of imperfect single crystals of calcium sulfate phases, takes place from the inside of the in itial aggregates. Hence, calcium sulfate follows a non-classical pathway. T2 - X-ray Powder Diffraction at DESY - new opportunities for research and industry CY - Online meeting DA - 22.06.2020 KW - Nucleation KW - Calcium sulfate KW - Diffraction KW - Scattering KW - Synchrotron KW - SAXS/WAXS PY - 2020 AN - OPUS4-50943 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kruschwitz, Sabine A1 - Halisch, M. A1 - Dlugosch, R. A1 - Prinz, Carsten T1 - Toward a better understanding of low-frequency electrical relaxation - An enhanced pore space characterization N2 - Relaxation phenomena observed in the electrical low-frequency range (approximately 1 mHz-10 kHz) of natural porous media like sandstones is often assumed to be directly related to the dominant (modal) pore throat sizes measured, for instance, with mercury intrusion porosimetry. Attempts to establish a universally valid relationship between pore size and peak Spectral Induced Polarization (SIP) relaxation time have failed, considering sandstones from very different origins and featuring great variations in textural and chemical compositions as well as in geometrical pore space properties. In addition working with characteristic relaxation times determined in Cole-Cole or Debye decomposition fits to build the relationship have not been successful. In particular, samples with narrow pore throats are often characterized by long SIP relaxation times corresponding to long “characteristic length scales” in these media, assuming that the diffusion coefficients along the electrical double layer were constant. Based on these observations, three different types of SIP relaxation can be distinguished. We present a new way of assessing complex pore spaces of very different sandstones in a multi-methodical approach to combine the benefits of mercury intrusion porosimetry, micro-computed tomography, and nuclear magnetic resonance. In this way, we achieve much deeper insight into the pore space due to the different resolutions and sensitivities of the applied methods to both pore constrictions (throats) and wide pores (pore bodies). We experimentally quantify pore aspect ratios and volume distributions within the two pore regions. We clearly observe systematic differences between three SIP relaxation types identified previously and can attribute the SIP peak relaxation times to measured characteristic length scales within our materials. We highlight selected results for a total of nine sandstones. It seems that SIP relaxation behavior depends on the size difference of the narrow pore throats to the wide pore bodies, which increases from SIP Type 1 to Type 3. KW - µ-CT KW - Spectral induced polarization KW - Nuclear magnetic resonance KW - Pore space PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509763 DO - https://doi.org/10.1190/GEO2019-0074.1 SN - 0016-8033 VL - 85 IS - 4 SP - MR257 EP - MR270 PB - Society of Exploration Geophysicists AN - OPUS4-50976 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kulow, Anicó A1 - de Oliveira Guilherme Buzanich, Ana A1 - Reinholz, Uwe A1 - Emmerling, Franziska A1 - Streli, C. A1 - Hampel, S. A1 - Fittschen, U. A1 - Radtke, Martin T1 - Full field X-ray fluorescence imaging with coded apertures N2 - Our aim is to develop a simple and inexpensive method for full field X-ray fluorescence imaging.We combine an energy-dispersive array detector with a coded aperture to obtain high resolution images. To obtain the information from the recorded image a reconstruction step is necessary. The reconstruction methods we have developed, were tested on simulated data and then applied to experimental data. The first tests were carried out at the BAMline @ BESSY II. This method enables the simultaneous detection of multiple elements, which is important e.g. in the field of catalysis. T2 - CONEXS 2020 CY - Newcastle, UK DA - 18.02.2020 KW - X-ray fluorescence spectroscopy KW - Coded apertures KW - Imaging KW - Iterative reconstruction PY - 2020 AN - OPUS4-50461 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - You, Zengchao A1 - Jakubowski, Norbert A1 - Panne, Ulrich A1 - Weidner, Steffen T1 - Separation of polysterene nanoparticles with different coatings using 2D off-line coupling of asymmetrical flow field flow fractionation and capillary electrophoresis N2 - The successful off-line coupling of asymmetrical flow field flow fractionation (AF4) and capillary electrophoresis (CE) for Separation of nanoparticles (NPs) with different surface coatings was shown. Two mixtures of polystyrene nanoparticles (PS-NPs) with comparable core sizes (20 nm and 50 nm) but different coatings (no coating/carboxyl-coated) were studied. Separation in either method resulted in non-baseline resolved or non-separated peaks. In contrast, two-dimensional off-line coupling of AF4 and CE resulted in clearly separated regions in their 2 D plots and can obviouly improve separation resolution. T2 - FFF 2020 CY - Wien, Austria DA - 23.02.2020 KW - Capillary electrophoresis KW - Nanoparticle PY - 2020 AN - OPUS4-50487 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kulow, Anicó A1 - de Oliveira Guilherme Buzanich, Ana A1 - Reinholz, Uwe A1 - Streli, C. A1 - Radtke, Martin T1 - On the way to full-field X-ray fluorescence spectroscopy imaging with coded apertures N2 - Imaging with X-rays is a challenging field, due to the optical properties of X-rays. The fabrication of appropriate optics is usually expensive and requires an elaborate manufacturing process. One simpler and less expensive possibility of imaging high energy radiation is coded aperture imaging, a technique well established in astrophysics and also used in nuclear medicine or radiation detection, e.g., for nuclear decommissioning. Our aim is to adapt coded aperture imaging for X-ray fluorescence spectroscopy in the nearfield. In this work we show theoretical considerations and preliminary simulations of Image formation through a coded aperture and three different reconstruction methods to prepare the experiments. We used a new mask based on an inverted modified uniformly redundant array (MURA) that could be used for the construction of a decoding mask for all investigated geometrical arrangements. The most commonly used reconstruction method, convoluting the detected image with a Decoding mask, does not always deliver satisfactory results. This is more noticeable for small distances between the object, mask and detector. Hence, we developed two new reconstruction methods, one based on iterative algebraic optimization and another one based on a genetic algorithm. Both show good performance even in those cases where the convolution method fails. This provides a basis for further investigations of the ideal parameters for near field coded aperture imaging and refinements of the algorithms. We performed first measurements with a coded aperture at the BAMline at BESSY II and could successfully reconstruct a test object from the obtained recorded images. KW - X-ray fluorescence spectroscopy KW - Coded aperture KW - Imaging KW - Iterative reconstruction PY - 2020 DO - https://doi.org/10.1039/c9ja00232d VL - 35 IS - 2 SP - 347 EP - 356 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-50459 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Diehn, S. A1 - Zimmermann, B. A1 - Tafintseva, V. A1 - Seifert, S. A1 - Bagcioglu, M. A1 - Ohlson, M. A1 - Weidner, Steffen A1 - Fjellheim, S. A1 - Kohler, A. A1 - Kneipp, Janina T1 - Combining Chemical Information From Grass Pollen in Multimodal Characterization N2 - The analysis of pollen chemical composition is important to many fields, including agriculture, plant physiology, ecology, allergology, and climate studies. Here, the potential of a combination of different spectroscopic and spectrometric methods regarding the characterization of small biochemical differences between pollen samples was evaluated using multivariate statistical approaches. Pollen samples, collected from three populations of the grass Poa alpina, were analyzed using Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, surface enhanced Raman scattering (SERS), and matrix assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS). The variation in the sample set can be described in a hierarchical framework comprising three populations of the same grass species and four different growth conditions of the parent plants for each of the populations. Therefore, the data set can work here as a model system to evaluate the classification and characterization ability of the different spectroscopic and spectrometric methods. ANOVA Simultaneous Component Analysis (ASCA) was applied to achieve a separation of different sources of variance in the complex sample set. Since the chosen methods and sample preparations probe different parts and/or molecular constituents of the pollen grains, complementary information about the chemical composition of the pollen can be obtained. By using consensus principal component analysis (CPCA), data from the different methods are linked together. This enables an investigation of the underlying global information, since complementary chemical data are combined. The molecular information from four spectroscopies was combined with phenotypical information gathered from the parent plants, thereby helping to potentially link pollen chemistry to other biotic and abiotic parameters. KW - Pollen KW - MALDI-TOF MS KW - FTIR KW - Raman KW - Multivariate analyses PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504822 DO - https://doi.org/10.3389/fpls.2019.01788 VL - 10 SP - 1788 AN - OPUS4-50482 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen A1 - Falkenhagen, Jana A1 - Kricheldorf, H. T1 - Polymer mass spectrometry at BAM with special emphasis on MALDI and ESI N2 - Since its introduction mass spectrometric techniques like Matrix-assisted Laser Desorption/ionization (MALDI) and Electrospray Ionization (ESI) have become indispensable for synthetic polymer analyses. Ideally, various polymer properties (monomer structure, masses, mass distribution, end groups) can be determined simultaneously. However, in real life these experiments are always affected by important structural parameters and instrumental limitations. A short introduction focussing on latest findings with respect to ionisation principles and mechanisms will be given. Recent results from our group will be presented and efforts to avoid common drawbacks of polymer mass spectrometry will be discussed. In this regard, MALDI - Imaging mass spectrometry and the 2D hyphenation of MS with different chromatographic separation techniques were especially useful, since they can provide additional information and reduce the complexity of polymer analyses. T2 - 21. European Symposium on Polymer Spectroscopy CY - Linz, Austria DA - 13.01.2020 KW - Mass spectrometry KW - MALDI-TOF MS KW - ESI-TOF MS KW - Polymer PY - 2020 AN - OPUS4-50260 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Kricheldorf, H. R. T1 - Matrix-assisted laser desorption/ionization behavior of neat linear and cyclic poly(L-lactide)s and their blends N2 - Numerous new tin catalysts that enable the synthesis of cyclic polylactides with broad variation in their molecular mass were recently developed. The abundance of cyclics in matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectra is, however, frequently reported to greatly exceed that of linears. Thus, the MALDI ionization behavior of various end-capped linear poly(L-lactide)s and one cyclic poly(L-lactide) was investigated and compared. Neat compounds and various blends of cyclic and linear species were prepared and studied under identical conditions with regard to sample preparation and instrumental condition, except for the laser power. For this purpose, two different MALDI-TOF mass spectrometers were applied. Our results reveal that cyclics indeed show a slightly better ionization in MALDI, although their ionization as a neat compound seems to be less effective than that of linear polylactides. The ionization of most linear polylactides investigated does not depend on the end group structure. However, linear polylactides containing 12-bromododecyl end groups reveal an unexpected saturation effect that is not caused by fragmentation of the polymer or the end group, or by electronic saturation of the detector digitizer. Furthermore, polylactides with a 2-bromoethyl end group did not show such a saturation effect. An overestimation of cyclic species in MALDI-TOF mass spectra of poly(L-lactide)s must be considered, but the commonly assumed peak suppression of linear polymers in mixtures of both structures can be excluded. KW - Polylactide KW - MALDI-TOF MS KW - Blends KW - Ionization PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504216 DO - https://doi.org/10.1002/rcm.8673 VL - 34 SP - e8673 PB - Wiley Online Libary AN - OPUS4-50421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Saleh, Maysoon I. A1 - Rühle, Bastian A1 - Wang, Shu A1 - Radnik, Jörg A1 - You, Yi A1 - Resch-Genger, Ute T1 - Assessing the protective effects of different surface coatings on NaYF4:YB3+, Er3+, upconverting nanoparticles in buffer and DMEM N2 - We studied the dissolution behavior of β NaYF4:Yb(20%), Er(2%) UCNP of two different sizes in biologically relevant media i.e., water (neutral pH), phosphate buffered saline (PBS), and Dulbecco’s modified Eagle medium (DMEM) at different temperatures and particle concentrations. Special emphasis was dedicated to assess the influence of different surface functionalizations, particularly the potential of mesoporous and microporous silica shells of different thicknesses for UCNP stabilization and protection. Dissolution was quantified electrochemically using a fluoride ion selective electrode (ISE) and by inductively coupled plasma optical emission spectrometry (ICP OES). In addition, dissolution was monitored fluorometrically. These experiments revealed that a thick microporous silica shell drastically decreased dissolution. Our results also underline the critical influence of the chemical composition of the aqueous environment on UCNP dissolution. In DMEM, we observed the formation of a layer of adsorbed molecules on the UCNP surface that protected the UCNP from dissolution and enhanced their fluorescence. Examination of this layer by X ray photoelectron spectroscopy (XPS) and mass spectrometry (MS) suggested that mainly phenylalanine, lysine, and glucose are adsorbed from DMEM. These findings should be considered in the future for cellular toxicity studies with UCNP and other nanoparticles and the design of new biocompatible surface coatings. KW - Fluorescence KW - Lifetime KW - Method KW - Quantification KW - Stability KW - Coating KW - Surface chemistry KW - Lanthanide KW - Fluoride KW - Electrochemistry KW - ICP-OES KW - Upconversion KW - Nano KW - Particle KW - Aging KW - Quality assurance KW - Mass spectrometry KW - XPS PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515984 DO - https://doi.org/10.1038/s41598-020-76116-z SN - 2045-2322 VL - 10 IS - 1 SP - 19318-1 EP - 19318-11 PB - Springer Nature CY - London AN - OPUS4-51598 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bhattacharya, Biswajit A1 - Das, S. A1 - Lal, G. A1 - Soni, S. R. A1 - Ghosh, A. A1 - Reddy, C. M. A1 - Ghosh, S. T1 - Screening, crystal structures and solubility studies of a series of multidrug salt hydrates and cocrystals of fenamic acids with trimethoprim and sulfamethazine N2 - Multidrug solids have a potential use to efficiently treat and control a superfluity of medical conditions. To address the current drawbacks of drug development in R&D, it was targeted to achieve new pharmaceutical solid forms of fenamic acids having improved solubility and thermal stability. Subsequently, five new multicomponent solids consisting of three salt hydrates of trimethoprim (TMP) with mefenamic acid (TMP-MFA-H2O), tolfenamic acid (TMP-TFA-H2O) and flufenamic acid (TMP-FFA-H2O), and two cocrystals of sulfamethazine (SFZ) with flufenamic acid (SFZ-FFA) and niflumic acid (SFZ-NFA) were prepared by liquid assisted grinding. Looking at the structures of active pharmaceutical ingredient (API) molecules, it was quite expected that a wide range of supramolecular synthons would lead to cocrystallization. New forms were characterized thoroughly by various solid-state techniques, including single crystal X-ray diffraction (SCXRD), which provided details of hydrogen bonding, molecular packing and interactions between drug and coformer. Kinetic solubility at pH 7.4 buffer study has been carried out and a comparison is made with respect to the parent drugs. A significant enhancement of NSAIDs solubility was observed in all salt hydrate systems of TMP. Thus with increasing physicochemical properties such as improved solubility further leads to the enhancement of bioavailability, which has implications to overcoming the formulation related problems of active pharmaceutical ingredients (APIs). KW - Cocrystals KW - Crystal engineering KW - Solubility PY - 2020 DO - https://doi.org/10.1016/j.molstruc.2019.127028 SN - 0022-2860 VL - 1199 SP - 127028 PB - Elsevier B.V. AN - OPUS4-49873 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lutz, C. A1 - Beuermann, S. A1 - Turek, T. A1 - Kunz, U. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Fittschen, U. T1 - Investigation on Vanadium Crossover in Nafion ™ and Novel PVDF Based Membranes for Vanadium Redox Flow Batteries N2 - Vanadium redoxflow batteries (VRFB)are currently one of the most promising candidates for stationary energys torage.For large scale applications the ion conducting membranes currently in use need to be improved. Ideally,they need to become more cost efficient and selective regarding the vanadium crossover.For a better understanding of the vanadium crossover, the development of reliable analytical methods and procedures, that elucidate uptake and transport of vanadium ions in the membrane, is necessary. First, we present the uptake of V2+,V3+,VO2+, VO2+ and V2O33+ in Nafion™ and in a novel membrane based onpoly(1,1-difluoroethylene)(PVDF). In preliminary discharge/charge experiments the ETFE-based membrane, the precursor of PVDF-based membrane, performed comparable to Nafion™. The methods of choice for speciation are UV/Vis and X-ray absorption near edge structure spectroscopy (XANES). According to the results, V2O33+, formed from VO2+ and VO2+, diffuses also into the membrane. In present models, the diffusion of V2O33+ is neglected. In addition,we study whether reactions could take place inside the membranes’ nanoscopic water body using XANES. Exposing Nafion™ from one site with V3+a nd from the other site with VO2+ realized the experiment. The results verified that VO2+ was formed inside the membrane. However,in present models reactions inside the membrane are neglected, too. T2 - Denver X-Ray Conference CY - Online meeting DA - 03.08.2020 KW - Batteries KW - BAMline KW - XANES KW - VRF PY - 2020 AN - OPUS4-51909 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fittschen, U. A1 - Lutz, C. A1 - Beuermann, S. A1 - Turek, T. A1 - Kunz, U. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin T1 - Element Species Determination in Polymer Electrolyte Membranes N2 - Polymer electrolyte membranes (PEM) are polymers which act as separator in an electrochemical cell and allow ionic charge flow to close the circuit. Widely used membranes are perfluorinated sulfonic-acid (PFSA) ionomers (e.g. Nafion™), a class of ion-conducting polymers with remarkable ion conductivity and chemical-mechanical stability. A nanoscopic water system around the sulfonic acid capped side-chains of the otherwise hydrophobic polymer allows the ion transport. Only approx. 14 molecules of water per sulfonic group are present in the fully hydrated state. In vanadium redox flow batteries (VRFB) ideally only protons are transported. The weak ion selectivity of Nafion™ is the main cause for the transportation of vanadium, briefly vanadium crossover, in VRFBs a system we have investigated more closely, lately. The consequences of crossover are a concentration imbalance and a self-discharge of the battery, which leads to a decrease of the capacity. The development of efficient energy storage systems is crucial for the transformation towards a renewable energy based economy. The VRFB has a great potential as a commercial electrochemical energy storage system due to properties including, but not limited to, no cross-contamination, a long cycle-life and a theoretically unlimited capacity. VRFB consists of two half-cells, which are linked to electrolyte tanks and separated by a membrane. The membrane plays a major role in overall cell performance. So far, vanadium transportation models, which include diffusion, migration, electroosmotic convection and pressure gradients, are inconsistent. There is no agreement in the literature on the diffusion coefficients of vanadium species (e.g. published diffusion coefficients of V2+ are located between 3.13·10-12 m²s-1 and 9.44·10-12 m²s-1) indicate that thevanadium crossover is not well understood and there is a lack on a more fundamental level. Since the membrane transport is the rate-determining step of the crossover as well as of the proton exchange it is extremely important to understand these phenomena on a fundamental level. This will eventually allow us to design better membranes. Alternative materials need to show equivalent performance compared with Nafion™ and ideally be more selective regarding ion cross-membrane transport.There are several options to approach the chemistry i.e. the interaction of dissolved and bound ions inside the confined water body of ionomeric membranes. Vanadium ions are a versatile model as UV/VIS data can be used to distinguish between the 5 species V2+, V3+, VO2+, VO2+ and V2O33+ of the electrolyte. Infrared spectroscopy has been applied to study the interaction of sulfonic groups and the ions. Molecular dynamic modeling is another approach to study the distribution and distances of ions. We now introduce X-ray absorption near edge structure spectroscopy (XANES) to study species and species changes inside Nafion™ and a novel membrane based on poly(1,1-difluoroethylene) (PVDF). We evaluated the methods and investigated the influence of irradiation, temperature and hydration on the measurements. T2 - Denver X-Ray Conference CY - Online meeting DA - 03.08.2020 KW - Batteries KW - BAMline KW - XANES PY - 2020 AN - OPUS4-51910 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fittschen, U. A1 - Hampel, S. A1 - Till, H. A1 - Gross, A. A1 - Kulow, Anicó A1 - de Oliveira Guilherme Buzanich, Ana A1 - Reinholz, Uwe A1 - Ingerle, D. A1 - Streli, C. A1 - Radtke, Martin T1 - Improving surface sensitive XRF using ink jet printing and information from the angle dependent signal N2 - Total Reflection X-ray Fluorescence (TXRF) is a small footprint, ressource efficient micro-analytical tool for trace elemental determination. However, depending on the matrix TXRF is also challenging in several ways: the preparation of a representative aliquot maybe difficult for slurries, shading effects and matrix effects may occur and the applicability of an IS maybe hampered by interferences (fitting may be impaired as well) or inhomogeneities. It is therefore crucial to understand and if applicable mitigate the influence of the before mentioned phenomena. We have used the small volume approach using pL droplets to study shading in TXRF previously.Using this approach thin specimens in a favorable geometry are prepared with a well defined morphology; this way minimizing matrix effects and shading. To be used as standard it is also necessary to determine the delivered elemental amounts. Here we will present on the performance of a commercial ink-jet printer cartridge to deliver defined volumes and elemental amounts. The microscopic specimens obtained have been successfully applied to determine relative sensitivities in TXRF and prepare references to study coded apertures in grazing incidence full field micro-XRF.The homogeneous lateral distribution of analyte and IS may be probed by micro-XRF, to obtain information on alikeness of analyte and IS. To study the alikeness of the in depth distribution (film-like or particle-like) angle scans can deliver valuable data. Here we present first results on angle scans using a prototype GIXRF set up and a commercial TXRF instrument. T2 - Denver X-Ray Conference CY - Online meeting DA - 03.08.2020 KW - TXRF KW - Coded Aperture PY - 2020 AN - OPUS4-51913 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen T1 - High molecular weight poly(l-lactide) via ring-opening polymerization with bismuth subsalicylate-The role of cocatalysts N2 - The catalytic potential of bismuth subsalicylate (BiSub), a commercial drug, for ring-opening polymerization (ROP) of L-lactide was explored by variation of co-catalyst and polymerization time. Various monofunctional phenols or carboxylic acids, aromatic ortho-hydroxy acids and diphenols were examined as potential co-catalysts. 2,2´-Dihydroxybiphenyl proved to be the most successful co-catalyst yielding weight average molecular weights (uncorrected Mw values up to 185 000) after optimization of reaction time and temperature. Prolonged heating (>1-2h) depending on catalyst concentration) caused thermal degradation. In polymerization experiments with various commercial Bi(III) salts a better alternative to BiSub was not found. By means of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry a couple of unusual and unexpected transesterification reactions were discovered. Finally, the effectiveness of several antioxidants and potential catalyst poisons was explored, and triphenylphosphine was found to be an effective catalyst poison. KW - Polylactide KW - MALDI-TOF MS KW - Ring-opening polymerization KW - Bismuth PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519513 DO - https://doi.org/10.1002/app.50394 SN - 0021-8995 VL - 138 IS - 19 SP - 50394 PB - Wiley AN - OPUS4-51951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radtke, Martin T1 - Machine learning: examples from BAMline N2 - Various applications for artificial intelligence in the context of spectroscopy will be presented. in particular, examples from BAMline will be presented. After a short introduction to synchrotron radiation, artificial intelligence algorithms for the quantification of X-ray fluorescence measurement are discussed. In the second example, information retrieval by natural language processing is discussed. T2 - Analytical Academy CY - Online meeting DA - 02.06.2020 KW - Machine learning KW - BAMline KW - XRF KW - Synchrotron PY - 2020 AN - OPUS4-51898 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Radtke, Martin A1 - Rakotondrajoa, A. T1 - Machine learning based quantification of synchrotron radiation-induced X-ray fluorescence measurements - a case study N2 - In this work, we describe the use of artificial neural networks for the quantification of X-ray fluorescence measurements. The training data were generated using Monte Carlo simulation, which avoided the use of adapted reference materials. The extension of the available data set by means of an ANN to generate additional data was demonstrated. Particular emphasis was put on the comparability of simulated and experimental data and how the influence of deviations can be reduced. The search for the optimal hyperparameter, manual and automatic, is also described. For the presented case, we were able to train a network with a mean absolute error of 0.1 weight percent for the synthetic data and 0.7 weight percent for a set of experimental data obtained with certified reference materials. KW - Machine learning KW - BAMline KW - XRF KW - Synchrotron KW - Neural network PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519008 DO - https://doi.org/10.1088/2632-2153/abc9fb SP - 1 EP - 16 PB - IOP Publishing AN - OPUS4-51900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - de Oliveira Guilherme Buzanich, Ana T1 - Trace element analysis with synchrotron radiation N2 - Trace elements are chemical elements whose concentration in a material is very low. The exact definition depends on the application and varies for example between 100 micrograms per gram in analytical chemistry and 1000 micrograms per gram in geology. The ability to detect trace elements fast and quantitatively is of great importance in many areas of science and technology. With its high brilliance and flexibility in the excitation conditions, synchrotron radiation is an ideal tool for detecting traces even in small sample quantities. In this contribution I will report about the use of X-ray fluorescence(XRF)for qualitative and quantitative element sensitiveanalysis. In addition to the fundamentals of XRF and its quantification methods, the advantages and problems of different geometries like e.g. microXRF, Total Reflection X-ray Fluorescence (TXRF)or Double Dispersive XRF (D²XRF) will be discussed. Practical examples from BAMline from the research fields of medicine, geology and archaeometry will complete the lecture. T2 - Denver X-Ray Conference CY - Online meeting DA - 03.08.2020 KW - Synchrotron KW - BAMline KW - XRF PY - 2020 AN - OPUS4-51890 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -