TY - JOUR A1 - Lange, M. A. A1 - Khan, I. A1 - Opitz, P. A1 - Hartmann, J: A1 - Ashraf, M. A1 - Qurashi, A. A1 - Prädel, L. A1 - Panthöfer, M. A1 - Cossmer, Antje A1 - Pfeifer, Jens A1 - Simon, Fabian A1 - von der Au, Marcus A1 - Meermann, Björn A1 - Mondeshki, M. A1 - Tahir, M. N. A1 - Tremel, W. T1 - A Generalized Method for High-Speed Fluorination of Metal Oxides by Spark Plasma Sintering Yields Ta3O7F and TaO2F with High Photocatalytic Activity for Oxygen Evolution from Water N2 - A general method to carry out the fluorination of metal oxides with poly(tetrafluoroethylene) (PTFE, Teflon) waste by spark plasma sintering (SPS) on a minute scale with Teflon is reported. The potential of this new approach is highlighted by the following results. i) The tantalum oxyfluorides Ta3O7F and TaO2F are obtained from plastic scrap without using toxic or caustic chemicals for fluorination. ii) Short reaction times (minutes rather than days) reduce the process time the energy costs by almost three orders of magnitude. iii) The oxyfluorides Ta3O7F and TaO2F are produced in gram amounts of nanoparticles. Their synthesis can be upscaled to the kg range with industrial sintering equipment. iv) SPS processing changes the catalytic properties: while conventionally prepared Ta3O7F and TaO2F show little catalytic activity, SPS-prepared Ta3O7F and TaO2F exhibit high activity for photocatalytic oxygen evolution, reaching photoconversion efficiencies up to 24.7% and applied bias to photoconversion values of 0.86%. This study shows that the materials properties are dictated by the processing which poses new challenges to understand and predict the underlying factors. KW - Fluorination KW - Oxygen evolution reaction KW - Photocatalysis KW - Spark plasma sintering KW - Tantalum oxyfluorides PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524329 DO - https://doi.org/10.1002/adma.202007434 VL - 23 IS - 20 SP - 7434 PB - Wiley‐VCH GmbH AN - OPUS4-52432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Li, X.M. A1 - Li, H.M. A1 - Zhang, Q.H. A1 - Lu, X.H. A1 - Li, S.Q. A1 - Koch, Matthias A1 - Polzer, J. A1 - Hackenber, R. A1 - Moniruzzaman, M. A1 - Khan, M. A1 - Kakoulides, E. A1 - Pak-Wing, K. A1 - Richy, A1 - Chi-Shing, N. A1 - Lu, T. A1 - Gui, E.M. A1 - Cheow, P.S. A1 - Teo, T.L. A1 - Rego, E. A1 - Garrido, B. A1 - Carvalho, L. A1 - Leal, R. A1 - Violante, F. A1 - Baek, S.Y. A1 - Lee, S. A1 - Choi, K. A1 - Kim, B. A1 - Bucar-Miklavcic, M. A1 - Hopley, C. A1 - Nammoonnoy, J. A1 - Murray, J. A1 - Wilson, W. A1 - Toman, B. A1 - Itoh, N. A1 - Gokcen, T. A1 - Krylov, A. A1 - Mikheeva, A. T1 - CCQM-K146 low-polarity analyte in high fat food: benzo a pyrene in olive oil N2 - The demonstration of competency and equivalence for the assessment of levels of contaminants and nutrients in primary foodstuffs is a priority within the 10-year strategy for the OAWG Track A core comparisons. The measurements are core challenges for reference material producers and providers of calibration Services. This key comparison related to low polarity analytes in a high fat, low protein, low carbohydrate food matrix and Benzo[a]pyrene in edible oil was the model System selected to align with this class within the OAWG strategy. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims (CMCs) made by national metrology institutes (NMIs) and designated institutes (Dis). 16 National Metrology Institutions participated in the Track A Key Comparison CCQM-K146 Low-Polarity Analyte in high fat food: Benzo[a]pyrene in Olive Oil. Participants were requested to evaluate the mass fractions, expressed in µg/kg, of Benzo[a]pyrene in the olive oil material. The KCRV was determined from the results of all NMIs/DIs participating in the key comparison that used appropriately validated methods with demonstrated metrological traceability. Different methods such as liquid-liquid extraction, GPC and SPE were applied in the sample pretreatment and HPLC-FLD, HPLC-MS/MS, and GC-MS or GC-MS/MS were applied for detection by the participants. The mass fractions for BaP were in the range of (1.78 to 3.09) µg/kg with Standard uncertainties of (0.026 to 0.54) µg/kg, with corresponding relative Standard uncertainties from 0.9% to 21%. Five labs withdrew their result from the Statistical evaluation of the KCRV for technical reasons. One lab was excluded from the KCRV evaluation, as they did not meet the CIPM metrological traceability requirements. A Hierarchical Bayes option was selected for the KCRV value, which was determined as 2.74 µg/kg with a Standard uncertainty of 0.03 µg/kg. The 10 institutes those were included in the calculation of the consensus KCRV all agreed within their Standard uncertainties. Successful participation in CCQM-K146 demonstrates the measurement capabilities in determining mass fraction of organic compounds, with molecular mass of 100 g/mol to 500 g/mol, having low polarity pKow < -2, in mass fraction range from 0.1 µg/kg to 1000 µg/kg in a high fat, low protein, low carbohydrate food matrix. KW - Metrology KW - CCQM KW - Food KW - PAH PY - 2020 DO - https://doi.org/10.1088/0026-1394/57/1a/08017 VL - 57 IS - 1a SP - 08017 AN - OPUS4-52435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Even, Morgane A1 - Juritsch, Elevtheria A1 - Richter, Matthias T1 - Measurement of very volatile organic compounds (VVOCs) in indoor air by sorbent-based active sampling: Identifying the gaps towards standardisation N2 - The ISO 16000-6 standard describes a method for the determination of volatile organic compounds (VOCs) in indoor and test chamber air by sorbent-based active sampling, thermal desorption and gas chromatography coupled with mass spectrometry (GC/MS). It also gives directions to adapt this methodology to very volatile organic compounds (VVOCs). Indeed, toxicologically based guideline values are being implemented for these compounds and it becomes necessary to measure them. But a comprehensive and robust measurement method is lacking. This work highlights the points that still need to be explored towards the standardisation of a suitable procedure: investigations on sorbent combinations, the suitability of chromatography columns and the use of gaseous standards are required. The biggest challenge remains in the fact that strong sorbents adsorb water together with VVOCs. Water may impair the analysis and the optimal approach to eliminate it is still to be found and integrated into the sampling strategy. KW - Solvents KW - Air analysis KW - VOC KW - Thermal desorption KW - Gas chromatography KW - ISO 16000-6 PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523919 DO - https://doi.org/10.1016/j.trac.2021.116265 VL - 140 SP - 116265 PB - Elsevier B.V. AN - OPUS4-52391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weber, K. A1 - Weber, M. A1 - Menneken, M. A1 - Kral, A. G. A1 - Mertz-Kraus, R. A1 - Geisler, T. A1 - Vogl, Jochen A1 - Tütken, T. T1 - Diagenetic stability of non-traditional stable isotope systems (Ca, Sr, Mg, Zn) in teeth – An in-vitro alteration experiment of biogenic apatite in isotopically enriched tracer solution N2 - Stable isotope ratios and trace element concentrations of fossil bones and teeth are important geochemical proxies for the reconstruction of diet and past environment in archaeology and palaeontology. However, since diagenesis can significantly alter primary diet-related isotope signatures and elemental compositions, it is important to understand and quantify alteration processes. Here, we present the results of in-vitro Alteration experiments of dental tissues from a modern African elephant molar reacted in aqueous solutions at 30 °C and 90 °C for 4 to 63 days. Dental cubes with ≈ 3 mm edge length, comprising both enamel and dentin, were placed into 2 mL of acidic aqueous solution enriched in different isotopes (25Mg, 44Ca, 67Zn, 86Sr, initial pH 1). Element and isotope distribution profiles across the reacted cubes were measured with LA-(MC-)ICP-MS and EMPA, while potential effects on the bioapatite crystal structure were characterised by Raman spectroscopy. In all experiments isotope ratios measured by LA-(MC-)ICP-MS revealed an alteration of the enamel in the outer ≈ 200–300 μm. In contrast, dentin was fully altered (≈ 1.4 mm) after one week at 90 °C while the alteration did not exceed a depth of 150–200 μm during the 30 °C experiments. Then, the tracer solution started also to penetrate through the enamel-dentin junction into the innermost enamel, however, leaving the central part of the enamel unaltered, even after three months. The Raman spectra suggest an initial demineralisation in the acidic environment while organic matter (i.e. collagen) is still preserved. In the 90 °C experiment, Raman spectra of the v1 PO4) band of the dentin shift over time towards synthetic hydroxylapatite patterns and the Ca (and Sr) concentrations in the respective solutions decrease. This indicates precipitation of newly formed apatite. Isotope and element concentration profiles across the dental tissues reveal different exchange mechanisms for different isotope systems. Magnesium is leached from enamel and dentin, while Zn is incorporated into the apatite crystal structure. However, the distribution of both elements is not affected in the innermost enamel where their concentrations do not change over the whole duration of the experiments. We found no correlation of reaction depth in the cubes and experimental duration, which might be caused by natural variability of the dental material already at the beginning of the experiment. Our alteration experiments in a closed system at high temperatures ≤90 °C and low initial pH demonstrate that at least the central part of mm-thick mammalian enamel apatite seems to be resistant against alteration preserving its pristine bioapatite mineral structure as well as its in-vivo elemental and isotopic composition. The experiments assess diagenetic alteration in a novel multi-proxy approach using in-situ analyses in high spatial resolution. It is demonstrated that the isotopes of Ca, Sr, Zn and Mg in the dentin are prone for diagenetic alteration, while enamel is more resistant against alteration and could be used for dietary and physiological reconstructions in fossil teeth. KW - Bioapatite KW - Isotopes KW - Raman spectroscopy KW - Diagenesis KW - LA-(MC-)ICP-MS KW - EPMA PY - 2021 DO - https://doi.org/10.1016/j.chemgeo.2021.120196 VL - 572 SP - 120196 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-52447 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gottu Mukkula, A. R. A1 - Kern, Simon A1 - Salge, M. A1 - Holtkamp, M. A1 - Guhl, Svetlana A1 - Fleischer, C. A1 - Meyer, Klas A1 - Remelhe, M. A1 - Maiwald, Michael A1 - Engell, S. T1 - An Application of Modifier Adaptation with Quadratic Approximation on a Pilot Scale Plant in Industrial Environment N2 - The goal of this work is to identify the optimal operating input for a lithiation reaction that is performed in a highly innovative pilot scale continuous flow chemical plant in an industrial environment, taking into account the process and safety constraints. The main challenge is to identify the optimum operation in the absence of information about the reaction mechanism and the reaction kinetics. We employ an iterative real-time optimization scheme called modifier adaptation with quadratic approximation (MAWQA) to identify the plant optimum in the presence of plant-model mismatch and measurement noise. A novel NMR PAT-sensor is used to measure the concentration of the reactants and of the product at the reactor outlet. The experiment results demonstrate the capabilities of the iterative optimization using the MAWQA algorithm in driving a complex real plant to an economically optimal operating point in the presence of plant-model mismatch and of process and measurement uncertainties. KW - Process Analytical Technology KW - Online NMR Spectroscopy KW - Process Industry KW - Iterative real-time optimization KW - Modifier adaptation KW - Plant-model mismatch KW - Reactor control KW - CONSENS PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524531 DO - https://doi.org/10.1016/j.ifacol.2020.12.685 SN - 1522-2640 VL - 53 IS - 2 SP - 11773 EP - 11779 PB - Elsevier CY - Amsterdam AN - OPUS4-52453 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Moufid, M. A1 - Bouchikhi, B. A1 - Tiebe, Carlo A1 - Bartholmai, Matthias A1 - El Bari, N. T1 - Assessment of outdoor odor emissions from polluted sites using simultaneous thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS), electronic nose in conjunction with advanced multivariate statistical approaches N2 - Poor air quality, particularly in urban areas, causes various diseases and degrades living standards. Air Quality could be affected by emissions of odor, Volatile Organic Compounds (VOCs), and other gases. Therefore, assessment and monitoring of odorous air quality using sensitive, simple, rapid, accurate and portable tools is very important for public health. This study aimed to characterize odor emissions to detect malfunctions in facilities and to prevent air pollution and olfactory nuisance in the environment. A gas chromatographic method, in conjunction with sensorial analysis were performed for odorous air samples analysis collected from neighborhood of Meknes city (Morocco). Advanced multivariate statistical approaches, such as Principal Components Analysis (PCA), Discriminant Function Analysis (DFA), Support Vector Machines (SVMs), and Hierarchical Cluster Analysis (HCA), were used to describe samples similarities. The electronic nose (e-nose) data processing exhibits a satisfactory discrimination between the odorous air samples. Twenty-four VOCs with known molecular formulas were identified with Thermal Desorption-Gas Chromatography-Mass Spectrometry (TD-GC-MS). A validated Partial Least Square (PLS) model foresees good calibration between e-nose measurement and TD-GCMS analysis. The finding indicates that TD-GC–MS approach in conjunction with e-nose unit could be suitable tool for environmental measurement-based odor emissions. KW - Electronic nose KW - TD-GC-MS KW - PLS regression KW - Multivariate analysis KW - Outdoor odor emissions PY - 2021 DO - https://doi.org/10.1016/j.atmosenv.2021.118449 SN - 1352-2310 VL - 256 SP - 118449 PB - Elsevier Ltd. AN - OPUS4-52626 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Meyer, A. A1 - Falkenhagen, Jana A1 - Kricheldorf, H. R. T1 - SnOct2-catalyzed and alcohol-initiated ROPs of L-lactide – About the influence of initiators on chemical reactions in the melt and the solid state N2 - SnOct2 (Sn(II) 2-ethylhexanoate) catalyzed ROPs of L-lactide were performed in bulk with eight different alcohols as initiators. The time was varied between 1 h and 24 h for all initiators. For two initiators the temperature was also lowered to 115 ◦C. Even-numbered chains were predominantly formed in all polymerizations at short times, but the rate of transesterification (e.g. even/odd equilibration) and the molecular weight distribution were found to depend significantly on the nature of the initiator. Observed transesterification reactions also continued in solid poly (L-lactide), and with the most active initiator, almost total equilibration was achieved even at 130 ◦C. This means that all chains including those of the crystallites were involved in transesterification reactions proceeding across the flat surfaces of the crystallites. The more or less equilibrated crystalline polylactides were characterized by DSC and SAXS measurements with regard to their melting temperature (Tm), crystallinity and crystal thickness. KW - Polylactide KW - MALDI-TOF MS KW - Crystallization KW - Catalysts KW - SAXS PY - 2021 DO - https://doi.org/10.1016/j.eurpolymj.2021.110508 VL - 153 SP - 110508 PB - Elsevier Ltd. AN - OPUS4-52633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brauckmann, C. A1 - Pramann, A. A1 - Rienitz, O. A1 - Schulze, A. A1 - Phukphatthanachai, Pranee A1 - Vogl, Jochen T1 - Combining Isotope Dilution and Standard Addition—Elemental Analysis in Complex Samples N2 - A new method combining isotope dilution mass spectrometry (IDMS) and standard addition has been developed to determine the mass fractions w of different elements in complex matrices: (a) silicon in aqueous tetramethylammonium hydroxide (TMAH), (b) sulfur in biodiesel fuel, and (c) iron bound to transferrin in human serum. All measurements were carried out using inductively coupled plasma mass spectrometry (ICP–MS). The method requires the gravimetric preparation of several blends (bi)—each consisting of roughly the same masses (mx,i) of the sample solution (x) and my,i of a spike solution (y) plus different masses (mz,i) of a reference solution (z). Only these masses and the isotope ratios (Rb,i) in the blends and reference and spike solutions have to be measured. The derivation of the underlying equations based on linear regression is presented and compared to a related concept reported by Pagliano and Meija. The uncertainties achievable, e.g., in the case of the Si blank in extremely pure TMAH of urel (w(Si)) = 90% (linear regression method, this work) and urel (w(Si)) = 150% (the method reported by Pagliano and Meija) seem to suggest better applicability of the new method in practical use due to the higher robustness of regression analysis. KW - Isotope dilution mass spectrometry KW - tandard addition KW - ICP-MS KW - lank characterization KW - Silicon KW - Sulfur KW - Transferrin KW - Tetramethylammonium hydroxide KW - Biodiesel fuel KW - Human serum PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526376 DO - https://doi.org/10.3390/molecules26092649 VL - 26 IS - 9 SP - 2649 PB - MDPI CY - Basel AN - OPUS4-52637 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grabicki, N. A1 - Nguyen, K. T. G. A1 - Weidner, Steffen A1 - Dumele, O. T1 - Confined Spaces in [n]Cyclo-2,7-pyrenylenes N2 - A set of strained aromatic macrocycles based on [n]cyclo2,7-(4,5,9,10-tetrahydro)pyrenylenes is presented with size dependent photophysical properties. The K-region of pyrene was functionalized with ethylene glycol groups to decorate the outer rim and thereby confine the space inside the macrocycle. This confined space is especially pronounced for n = 5, which leads to an internal binding of up to 8.0×104 M–1 between the ether-decorated [5]cyclo-2,7-pyrenylene and shape complementary crown ether–cation complexes. Both, the ether-decorated [n]cyclo-pyrenylenes as well as one of their host–guest complexes have been structurally characterized by single crystal X-ray analysis. In combination with computational methods the structural and thermodynamic reasons for the exceptionally strong binding have been elucidated. The presented rim confinement strategy makes cycloparaphenylenes an attractive supramolecular host family with a favorable, size-independent read-out signature and binding capabilities extending beyond fullerene guests. KW - Cycloparaphenylenes KW - Host–guest systems KW - Macrocycles KW - Molecular recognition KW - Supramolecular chemistry PY - 2021 DO - https://doi.org/10.1002/anie.202102809 SN - 1433-7851 VL - 60 IS - 27 SP - 1 EP - 7 PB - Wiley VCH AN - OPUS4-52517 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiesner, Yosri A1 - Altmann, Korinna A1 - Braun, U. T1 - Determination of Microplastic Mass Content by Thermal Extraction Desorption Gas Chromatography– Mass Spectrometry N2 - The scientific and practical challenge of detecting microplastics (MPs) in the environment in a targeted and rapid manner is solved by innovative coupling of thermogravimetric analysis with mass spectrometric methods. Fast identification and quantitative determination of most thermoplastic polymers and elastomers is possible by using thermal extraction Desorption gas chromatography–mass spectrometry (TED-GC–MS). KW - Microplastics KW - Mikroplastik KW - TED-GC/MS KW - Microplastics analytic KW - Mikroplastik Massegehalt PY - 2021 VL - 17 IS - 3 SP - 2 EP - 7 PB - MultiMedia (UK) LLC CY - Cranbury AN - OPUS4-52570 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -