TY - JOUR
A1 - You, Zengchao
A1 - Hoffmann, V.
A1 - Morcillo, Dalia
A1 - Agudo Jácome, Leonardo
A1 - Leonhardt, Robert
A1 - Winckelmann, Alexander
A1 - Richter, Silke
A1 - Recknagel, Sebastian
A1 - Abad Andrade, Carlos Enrique
T1 - Investigation of aluminum current collector degradation in lithium-ion batteries using glow discharge optical emission spectrometry
N2 - In this work, we employed glow discharge optical emission spectrometry (GD-OES) depth profiling as a fast and semi-quantitative method to investigate the aluminum (Al) current collector degradation in commercial lithium cobalt oxide (LCO) pouch cells with no Al2O3 pretreatment. After battery aging, a heterogeneous deposit was found on the surface of the cathode. Gray hotspot areas within an extensive pale white region were formed. Consistent with energy dispersive X-ray (EDX) analysis of micro-cross sections milled via targeted focused ion beam (FIB), an Al-containing layer of approximately 3 µm can be observed using GD-OES. We attribute one main cause of this layer is the degradation of the Al current collector. The nonuniform growth of this layer was investigated by performing GD-OES depth profiling at different in-plane positions. We found that the gray area has a higher mass concentration of Al, probably in metallic form, whereas the white area was probably covered more homogeneously with Al2O3, resulting from the inhomogeneous distribution of the pitting positions on the current collector. Compared to FIB-EDX, GD-OES enables a faster and more convenient depth profile analysis, which allows the more productive characterization of lithium-ion batteries (LIBs), and consequently benefits the development of preferable battery materials.
KW - GD-OES
KW - depth profiles
KW - Li-ion battery
KW - battery aging mechanism
KW - current collector corrosion
PY - 2023
DO - https://doi.org/10.1016/j.sab.2023.106681
SN - 0584-8547
VL - 205
SP - 106681
PB - Elsevier B.V.
CY - Amsterdam, Netherlands
AN - OPUS4-57383
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
A1 - Bremser, Wolfram
A1 - Pfeifer, Dietmar
A1 - Spieles, Monika
A1 - Hoffmann, Angelika
A1 - DeRose, P.C.
A1 - Zwinkels, J. C.
A1 - Gauthier, F.
A1 - Ebert, B.
A1 - Taubert, D.
A1 - Monte, C.
A1 - Voigt, J.
A1 - Hollandt, J.
A1 - Macdonald, R.
T1 - State-of-the art comparability of corrected emission spectra. 1. spectral correction with physical transfer standards and spectral fluorescence standards by expert laboratories
N2 - The development of fluorescence applications in the life and material sciences has proceeded largely without sufficient concern for the measurement uncertainties related to the characterization of fluorescence instruments. In this first part of a two-part series on the state-of-the-art comparability of corrected emission spectra, four National Metrology Institutes active in high-precision steady-state fluorometry performed a first comparison of fluorescence measurement capabilities by evaluating physical transfer standard (PTS)-based and reference material (RM)-based calibration methods. To identify achievable comparability and sources of error in instrument calibration, the emission spectra of three test dyes in the wavelength region from 300 to 770 nm were corrected and compared using both calibration methods. The results, obtained for typical spectrofluorometric (0°/90° transmitting) and colorimetric (45°/0° front-face) measurement geometries, demonstrated a comparability of corrected emission spectra within a relative standard uncertainty of 4.2% for PTS- and 2.4% for RM-based spectral correction when measurements and calibrations were performed under identical conditions. Moreover, the emission spectra of RMs F001 to F005, certified by BAM, Federal Institute for Materials Research and Testing, were confirmed. These RMs were subsequently used for the assessment of the comparability of RM-based corrected emission spectra of field laboratories using common commercial spectrofluorometers and routine measurement conditions in part 2 of this series (subsequent paper in this issue).
KW - Fluorescence
KW - Photoluminescence
KW - Dye
KW - Uncertainty
KW - Method comparison
KW - Standard
KW - Spectral correction
KW - Spectral fluorescence standard
PY - 2012
DO - https://doi.org/10.1021/ac2034503
SN - 0003-2700
SN - 1520-6882
VL - 84
IS - 9
SP - 3889
EP - 3898
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-25838
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tamschick, S.
A1 - Rozenblut-Kościsty, B.
A1 - Ogielska, M.
A1 - Lehmann, Andreas
A1 - Lymberakis, P.
A1 - Hoffmann, F.
A1 - Lutz, I.
A1 - Kloas, W.
A1 - Stöck, M.
T1 - Sex reversal assessments reveal different vulnerability to endocrine disruption between deeply diverged anuran lineages
N2 - Multiple anthropogenic stressors cause worldwide amphibian declines. Among several poorly investigated causes is global pollution of aquatic ecosystems with endocrine disrupting compounds (EDCs). These substances interfere with the endocrine system and can affect the sexual development of vertebrates including amphibians. We test the susceptibility to an environmentally relevant contraceptive, the artificial estrogen 17α-ethinylestradiol (EE2), simultaneously in three deeply divergent systematic anuran families, a model-species, Xenopus laevis (Pipidae), and two non-models, Hyla arborea (Hylidae) and Bufo viridis (Bufonidae). Our new approach combines synchronized tadpole exposure to three EE2-concentrations (50, 500, 5,000 ng/L) in a flow-through-system and pioneers genetic and histological sexing of metamorphs in non-model anurans for EDC-studies. This novel methodology reveals striking quantitative differences in genetic-male-to-phenotypic-female sex reversal in non-model vs. model species. Our findings qualify molecular sexing in EDC-analyses as requirement to identify sex reversals and state-of-the-art approaches as mandatory to detect speciesspecific vulnerabilities to EDCs in amphibians.
KW - Endocrine disruption
KW - 17α-ethinylestradiol (EE2)
KW - Mass spectrometry
KW - Sex reversal
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-357797
DO - https://doi.org/10.1038/srep23825
SN - 2045-2322
VL - 6
SP - Article No. 23825, 1
EP - 8
PB - Nature publishing group
AN - OPUS4-35779
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hoffmann, Marie
T1 - Scandium and scandium-aluminium alloy production from European metallurgical by-products
N2 - The SCALE Project is a Horizon2020 Project (GA°730105) that aims to develope a secure supply chain for Scandium in Europe. To achieve that, the whole value chain is investigated and new methodologies and techniques are being developed. In BAM we are characterizing potential Scandium-bearing industrial by-products.
T2 - Poster presentation during Exploration Geology Short Course DMG
CY - Freiburg, Germany
DA - 19.02.2018
KW - Scandium
KW - Red Mud
KW - Aluminium
KW - SCALE
PY - 2018
AN - OPUS4-46539
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hoffmann, Marie
T1 - Scandium in industriellen Reststoffen - Die Suche nach der Nadel im Heuhaufen
N2 - Im Zusammenhang mit dem Horizon2020 geförderten Projekt SCALE (GA°730105) untersuchen wir an der BAM die Scandium Spezies in industriellen Restsoffen wie zum Beispiel Rotschlamm. Dabei kommen Methoden wie Elektronenmikroskopie, LA-ICP-MS und auch X-ray Adsorption near edge structure an Synchrotron-Lichtquellen zum Einsatz. Das Verständnis der Bindungsformen des Scandiums soll im Weiteren helfen, metallurgische Gewinnungsmethoden zu verbessern und anzupassen.
T2 - Posterpräsentation während des Themenfeldtags Umwelt
CY - Berlin, Germany
DA - 18.10.2018
KW - Scandium
KW - Rotschlamm
KW - Aluminium
KW - SCALE
PY - 2018
AN - OPUS4-46540
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hoffmann, Marie
T1 - Recovery potential of Scandium and other critical raw materials from European industrial by-products
N2 - Technological evolution and modern advances in the field of renewable energies are connected to an increasing demand on critical raw materials and especially technological metals.
Recently, interest in the element scandium (Sc) has started to grow due to its positive influence on material properties e.g. in high performance-alloys, solid-oxide-fuel cells and solid-state lasers. Therefore, a rise in value and demand is expected in the near future.
This study focuses on the reliable and sufficient methodology of measuring Sc and other critical raw materials in secondary waste products from the Al2O3- and Ti2O producing industry. It also targets the examination of Sc-bearing phases and their potential influence in the recovery of Sc from above mentioned materials. Essentially, chemical and structural analyses and characterization of European red muds and its Sc-bearing mineral phases are carried out.
Furthermore, analogue investigations are performed for filter cakes and acid slurries that incur during TiO2 production.
Red muds and TiO2 filter cakes from several European countries have been analyzed by X-ray diffraction, X-ray-fluorescence, ICP-MS and -OES. Analytical procedures performed are based on previous studies and different methods are tested and compared to ensure reliable data from ICP-MS and -OES measurements.
Red mud samples were found to contain ~60-100 mg/kg Sc. Main mineral phases are Hematite, Gibbsite, Boehmite, Cancrinite, Diaspore, Perovskite, Rutile, Katoite and Quartz in variable amounts. Samples from TiO2-production contain up to 400 mg/kg of Sc and significant amounts of niobium and cerium. The main mineral phases are Rutile, Calcite, Quartz, Graphite and Iron-Oxide-Chloride. Generally, it is assumed that Sc is associated with iron and titanium-bearing phases such as Ilmenite and Rutile as it was found in REE deposits in China. Hence, These phases are studied in more detail with advanced structural analyses such as X-ray Absorption near edge structure (XANES) and point-based mineral chemistry analyses by electron microprobe. The study is incorporated in the SCALE project (GA No. 730105) funded by European Union's Horizon 2020 research and innovation program and aims to secure a European supply chain for Sc from metallurgical by-products.
T2 - GeoBremen 2017
CY - Bremen, Germany
DA - 24.09.2017
KW - Red mud
KW - Critical raw materials
KW - Industrial byproducts
PY - 2017
AN - OPUS4-43452
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogel, Christian
A1 - Hoffmann, Marie
A1 - Taube, Mareike
A1 - Krüger, O.
A1 - Baran, R.
A1 - Adam, Christian
T1 - Uranium and thorium species in phosphate rock and sewage sludge ash based phosphorus fertilizers
N2 - Phosphorus (P) is an essential element for all forms of life and is thus often applied as phosphate rock-based P-fertilizers in agriculture to enable continuous farming. However, these P-fertilizers contain also hazardous uranium (U) and thorium (Th), up to 660 and 220 mg/kg, respectively. On the contrary, novel P-fertilizers made from sewage sludge (ash) contain only low mass fractions of U and Th. In addition to the total amount of U and Th in P-fertilizers, their mobility and bioavailability is important, which depends to a large extent on their chemical state, especially oxidation state and chemical bonding. Thus, we analyzed their chemical state in various P-fertilizers by U and Th L3-edge HERFD-XANES spectroscopy. Phosphate rocks and sewage sludge-based P-fertilizers contain mainly U(IV) compounds which have only a low bioavailability. In contrast, acidic treatment of phosphate rock to produce super phosphates lead to an oxidation to U(VI) compounds (including formation of uranium phosphates) with a strongly increased bioavailability. On the contrary, all analyzed P-fertilizers contain Th in form of strongly insoluble phosphates and oxides with a low bioavailability. Additionally performed water extractions and Diffusive Gradients in Thin-films (DGT) experiments support these findings.
KW - Phosphorus fertilizer
KW - Sewage sludge
KW - X-ray absorption near-edge structure (XANES) spectroscopy
KW - Diffusive Gradients in Thin-films (DGT)
KW - Extraction
PY - 2020
DO - https://doi.org/10.1016/j.jhazmat.2019.121100
SN - 0304-3894
VL - 382
SP - 121100, 1
EP - 6
AN - OPUS4-48872
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hoffmann, Heike
A1 - Stephan, Ina
A1 - Schwibbert, Karin
ED - Bismayer, U.
ED - Schleicher, H.
T1 - Auswirkung von Bioziden auf die Bakterienpopulation im Boden
T2 - 80. Jahrestagung der Deutschen Mineralogischen Gesellschaft
CY - Hamburg, Deutschland
DA - 2002-09-08
PY - 2002
N1 - Geburtsname von Schwibbert, Karin: Göller, K. - Birth name of Schwibbert, Karin: Göller, K.
VL - 14
IS - 1
SP - 72
CY - Hamburg
AN - OPUS4-2540
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hoffmann, Heike
T1 - Auswirkung von Bioziden auf die Bakterienpopulation im Boden
T2 - 80. Jahrestagung der Deutschen Mineralogischen Gesellschaft
CY - Hamburg, Germany
DA - 2002-09-08
PY - 2002
N1 - Geburtsname von Schwibbert, Karin: Göller, K. - Birth name of Schwibbert, Karin: Göller, K.
AN - OPUS4-3338
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mair, Georg W.
A1 - Hoffmann, Martin
A1 - Saul, Herbert
A1 - Spode, Manfred
T1 - Betrachtung von Grenzwerten der Restfestigkeit von Composite-Druckgefäßen - Teil 2: Extrapolation der Lastwechsel-Degradation
N2 - Die aktuelle Praxis, auch die wiederkehrende Prüfung von Druckgefäßen aus Verbundwerkstoffen primär auf die hydraulische Innendruckprüfung abzustellen, ist sowohl im Hinblick auf die Schädigung der Prüfmuster als auch ihrer Aussagekraft kritisch zu bewerten. Daher bringt die BAM Bundesanstalt für Materialforschung und -prüfung zur Absicherung bei der Zulassung von Prüffristen für Composite-Druckgefäße, die älter als fünf Jahre sind, einen neuen Ansatz zur Anwendung. Er ermöglicht eine Zustandsbeschreibung der Population eines Baumusters auf der Basis wiederholt betriebsbegleitend zerstörender Prüfungen. Ein wesentlicher Aspekt dieses Ansatzes ist die Prognose der sicheren Restlebensdauer. Hierbei stellt der Effekt des übermäßigen Verlusts an hydraulischer Lastwechselfestigkeit im Sinne einer Degradation der Festigkeit einen kritischen Punkt in der Prognose der Sicherheit bis zum Lebensdauerende dar.
KW - Faserverbundwerkstoffe
KW - Druckgefäße
KW - Restfestigkeit
KW - Degradation
KW - Stichprobenprüfung
KW - Hydraulische Lastwechselprüfung
KW - Lebensdauer
KW - Überlebenswahrscheinlichkeit
KW - Lastwechselempfindlichkeit
PY - 2012
SN - 2191-0073
VL - 2
IS - 10
SP - 38
EP - 43
PB - Springer-VDI-Verl.
CY - Düsseldorf
AN - OPUS4-26672
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mair, Georg W.
A1 - Pöschko, Pascal
A1 - Hoffmann, Martin
A1 - Schoppa, André
A1 - Spode, Manfred
T1 - Betrachtung von Grenzwerten der Restfestigkeit von Composite-Druckgefäßen - Teil 1: Kriterien der hydraulischen Lastwechselprüfung
N2 - Die aktuelle Praxis, auch die wiederkehrende Prüfung von Druckgefäßen aus Verbundwerkstoffen primär auf die hydraulische Innendruckprüfung abzustellen, ist sowohl bezüglich der Schädigung der Prüfmuster als auch ihrer Aussagekraft als kritisch zu bewerten. Die Bundesanstalt für Materialforschung und -prüfung BAM bringt daher bei der Zulassung von Prüffristen für Composite-Druckgefäße von mehr als fünf Jahren zur Absicherung einen neuen Ansatz zur Anwendung. Er ermöglicht eine Zustandsbeschreibung der Population eines Baumusters auf der Basis wiederholt betriebsbegleitend zerstörender Prüfungen. Nachfolgend wird erläutert, wie die statistische Auswertung von Stichproben und deren perspektivische Extrapolation erfolgen und wie Zuverlässigkeitsgrenzwerte von der Größe von Druckgefäßen abhängig gemacht werden können, sowie welchen Einfluss der reale Gasdruck auf die Sicherheitsbewertung im Rahmen des Ansatzes der BAM hat. Insbesondere wird in das zentrale Arbeitsdiagramm des Ansatzes eingeführt und erläutert, wie dieses verwendet werden kann. Hierzu wird auch ausgeführt, wie die Füllzyklenzahl und die Lastwechselfestigkeit über die neu eingeführte Größe der spezifischen Füllempfindlichkeit zusammenhängen.
KW - Restfestigkeiten
KW - Degradation
KW - Betriebssicherheit
KW - Hydraulische Lastwechselprüfung
KW - Streuung
KW - Ausfallwahrscheinlichkeit
KW - Lastwechselempfindlichkeit
PY - 2012
SN - 2191-0073
VL - 2
IS - 7/8
SP - 30
EP - 38
PB - Springer-VDI-Verl.
CY - Düsseldorf
AN - OPUS4-26199
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogel, Christian
A1 - Hoffmann, Marie
A1 - Krüger, O.
A1 - Murzin, V.
A1 - Caliebe, W.
A1 - Adam, Christian
T1 - Chromium (VI) in phosphorus fertilizers determined with the diffusive gradients in thin-films (DGT) technique
N2 - Phosphorus (P) fertilizers from secondary resources became increasingly important in the last years. However, these novel P-fertilizers can also contain toxic pollutants such as chromium in its hexavalent state (Cr(VI)). This hazardous form of chromium is therefore regulated with low limit values for agricultural products even though the correct determination of Cr(VI) in these fertilizers may be hampered by redox processes, leading to false results. Thus, we applied the novel diffusive gradients in thin-films (DGT) technique for Cr(VI) in fertilizers and compared the results with the standard wet chemical extraction method (German norm DIN EN 15192) and Cr K-edge X-ray Absorption near-edge structure (XANES) spectroscopy. We determined an overall good correlation between the wet chemical extraction and the DGT method. DGT was very sensitive and for most tested materials selective for the analysis of Cr(VI) in P-fertilizers. However, hardly soluble Cr(VI) compounds cannot be detected with the DGT method since only mobile Cr(VI) is analyzed. Furthermore, Cr K-edge XANES spectroscopy showed that the DGT binding layer also adsorbs small amounts of mobile Cr(III) so that Cr(VI) values are overestimated. Since certain types of the P fertilizers contain mobile Cr(III) or partly immobile Cr(VI), it is necessary to optimize the DGT binding layers to avoid aforementioned over- or underestimation. Furthermore, our investigations showed that the Cr K-edge XANES spectroscopy technique is unsuitable to determine small amounts of Cr(VI) in fertilizers (below approx. 1% of Cr(VI) in relation to total Cr).
KW - Phosphorus fertilizer
KW - Sewage sludge ash
KW - Diffusive Gradients in thin films (DGT)
KW - Chemical extraction
KW - XANES spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509578
DO - https://doi.org/10.1007/s11356-020-08761-w
SN - 0944-1344
VL - 27
SP - 24320
EP - 24328
PB - Springer
AN - OPUS4-50957
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hoffmann, Marie
T1 - Novel approaches to Sc species investigation in bauxite residues by x ray absorption near edge structure spectroscopy
N2 - In a rapidly evolving world, the demand on raw materials is increasing steadily and many technologies are dependent on a secure supply of hi-tech metals. Recently, scandium (Sc) has attracted attention since its use in high strength Al-alloys and solid-oxide-fuel-cells strongly improves the performance of those materials.
The element Sc is not exceptionally rare but quite resistant to geochemical enrichment processes, it is scarcely found enriched to high concentrations and is recovered as a by-product. Since Sc enrichment in Greek bauxite residues was shown by Ochsenkühn-Petropoulou et. al (1994), intensive research on this material and development of efficient Sc-recovery methods is ongoing.
This study investigates Sc-bearing species in bauxite residues from alumina production. It aims to provide direct evidence about the Sc-speciation’s in those secondary resources and tries to find the link to speciation’s in primary resources, e.g. bauxites and laterites.
Therefore, Sc K edge XANES (X-ray absorption near edge structure) spectroscopy is performed using synchrotron radiation to determine the presence of certain Sc-components and distinguish between adsorbed and chemically bonded Sc as was shown for lateritic deposits in Australia by Chassé et al. 2016. For comparison, reference standards of Sc-bearing and Sc-adsorbed species are synthesized. Indirect inferences from leaching behavior of bauxites, in cases supported by analyses with LA-ICP-MS, suggest Sc to be associated with either iron- or aluminum phases (Vind et al. 2017); (Suss et al.). It remains unclear how different primary materials influence Sc-speciation in the bauxite residue. Therefore, a comparison between different European bauxite residues is made in this study. The investigations should help to understand Sc chemistry and
behavior in different primary and secondary materials and provide fundamentals for metallurgical processing. The research is incorporated in the SCALE project (GA No. 730105) funded by EU Horizon 2020 research and innovation program.
T2 - DMG Tagung GeoMünster
CY - Westfälische Wilhelms-Universität Münster, Germany
DA - 22.09.2019
KW - Scandium
KW - Bauxite Residue
KW - Red Mud
KW - XANES
PY - 2019
AN - OPUS4-49389
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Angeli, J.
A1 - Bengtson, A.
A1 - Bogaerts, A.
A1 - Hoffmann, V.
A1 - Hodoroaba, Vasile-Dan
A1 - Steers, E.
T1 - Glow discharge optical emission spectrometry: moving towards reliable tion film analysis - a short review
N2 - Glow discharge optical emission spectroscopy (GD-OES) is briefly reviewed, with particular reference to topics relevant to the application field of near surface and thin film analysis. The special needs and requirements for thin film analysis, in contrast to coating and bulk analysis, are pointed out. A task list is developed which shows the requirements of further developments to the technique and the fundamentals. The state-of-the-art is presented in measurement technique, GD source control and design, the effect of traces of molecular gases, correction and quantification procedures, contributions of modelling and, finally, reference materials for thin film analysis.
PY - 2003
DO - https://doi.org/10.1039/b301293j
SN - 0267-9477
SN - 1364-5544
VL - 18
IS - 6
SP - 670
EP - 679
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-2533
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoffmann, V.
A1 - Dorka, R.
A1 - Wilken, L.
A1 - Hodoroaba, Vasile-Dan
A1 - Wetzig, K.
T1 - Present possibilities of thin-layer analysis by GDOES
N2 - The analysis of thin layers of thickness 100 nm has become a new field of application for glow discharge optical emission spectroscopy (GDOES). In this paper an overview is given of the experiences and possibilities gained by the authors in later years at their research, development and application of GDOES.
During GDOES analysis of a multilayer system the depth resolution was determined using the inverse maximal slope method. Under optimized discharge conditions a depth resolution of 25 nm at 100 nm depth was achieved. The gas flow in a Grimm-type source for glow discharge mass spectrometry (GDMS) was simulated and a correlation between calculated pressure and crater shape was found. Cleanness of the sample and source turned out to be essential for a fast stabilization time and reduction of the influence of light elements and molecules. Thereby, a 10 nm layer at the top surface of a sample could be quantified. Apart from the influence of density, the reflectivity of the sample surface is discussed. It is shown that a high sample reflectivity can cause up to 100% more light to be measured by the spectrometer.
KW - GDOES
KW - GDMS
KW - Thin-layer analysis
PY - 2003
DO - https://doi.org/10.1002/sia.1575
SN - 0142-2421
SN - 1096-9918
VL - 35
IS - 7
SP - 575
EP - 582
PB - Wiley
CY - Chichester
AN - OPUS4-2624
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
A1 - Hoffmann, V.
A1 - Steers, E. B. M.
T1 - Exploitation of the hydrogen effect on an analytical glow discharge
T2 - Final General Meeting of the EU-GDS Network
CY - Wiener Neustadt, Austria
DA - 2002-03-02
PY - 2002
SP - 1(?)
EP - 6(?)
AN - OPUS4-1467
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gonzales-Gago, C.
A1 - Smid, P.
A1 - Hofmann, T.
A1 - Venzago, C.
A1 - Hoffmann, V.
A1 - Gruner, W.
A1 - Pfeifer, Jens
A1 - Richter, Silke
A1 - Kipphardt, Heinrich
T1 - Investigations of matrix independent calibration approaches in fast flow glow discharge mass spectrometry
N2 - The performance of glow discharge mass spectrometry (GD-MS) is investigated for the accurate quantification of metallic impurities and oxygen in solid samples using the fast flow source GD-MS instrument ELEMENT GD.
Different quantification approaches based on relative and absolute sensitivity factors are evaluated for the determination of metallic impurities using three sample matrixes (Al, Cu and Zn). The effect of the discharge conditions (voltage, current, discharge gas pressure/flow) on the sensitivity is investigated and the parameters are optimized to favour matrix independent calibrations. Improved standard relative sensitivity factors (StdRSFs) are calculated under optimal conditions based on multi-matrix calibrations. The sputtering rate corrected calibration is also presented as a multi-matrix calibration approach.
The capabilities of GD-MS for oxygen determination are also investigated using a set of new conductive samples containing oxygen with mass fractions in the percent range in three different matrices (Al, Mg and Cu) produced by a sintering process. Poor limits of detection (in the order of g/kg) were obtained as consequence of the reduced sensitivity of oxygen in GD-MS and high oxygen background signal intensity as well as its variations. The absolute sensitivity procedure is shown as a matrix-independent approach, which provides quantitative values consistent with those obtained by carrier gas hot extraction (CGHE).
KW - Fast flow GD
KW - GDMS
KW - Calibration
KW - Matrix independent calibration
PY - 2019
DO - https://doi.org/10.1039/c9ja00023b
SN - 1364-5544
SN - 0267-9477
VL - 34
IS - 6
SP - 1109
EP - 1125
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-47842
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Steers, E.B.M.
A1 - Hoffmann, V.
A1 - Unger, Wolfgang
A1 - Paatsch, Wolfgang
A1 - Wetzig, K.
T1 - Influence of hydrogen on the analytical figures of merit of glow discharge optical emission spectroscopy - friend or foe?
PY - 2003
DO - https://doi.org/10.1039/b305384a
SN - 0267-9477
SN - 1364-5544
VL - 18
SP - 521
EP - 526
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-2290
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Steers, E.B.M.
A1 - Hoffmann, V.
A1 - Wetzig, K.
T1 - The effect of small quantities of hydrogen on a glow discharge in neon. Comparison with the argon case
N2 - In order to gain an insight into the numerous effects caused by the addition of hydrogen to an argon glow discharge, comparison experiments have been made with neon as carrier gas. In some cases the effects are diminished or even disappear. Using various bulk samples, such as copper, steel and titanium, sputtered in a neon glow discharge, the intensities of the analytical lines are affected by the presence of hydrogen in different ways from argon; the dependent parameter (the discharge current in this work) and the sputtering rate vary less than in argon. The crater shape and roughness are also affected and these effects are discussed qualitatively. Probably the most important spectral feature caused by hydrogen in the case of a discharge in argon is the emission of a continuous background. This does not appear in neon under similar discharge conditions and only weakly at high hydrogen concentrations. This supports the suggestion, made in previous work, that an effective quenching process of the argon metastables (11.55 and 11.72 eV) is Penning excitation of the hydrogen molecules, and subsequent decay to a repulsive state with emission of the continuum; in neon the energy match does not occur. It was found with neon, as with argon, that similar features occur as when hydrogen is introduced in different ways into the glow discharge: as a molecular gas contamination or as a constituent of the sample. Glow discharge mass spectrometry (GD-MS) experiments carried out with both argon and neon support the results obtained by optical emission spectrometry (OES) and provide further relevant information.
PY - 2001
DO - https://doi.org/10.1039/b007527m
SN - 0267-9477
SN - 1364-5544
VL - 16
SP - 43
EP - 49
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-6887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Hoffmann, V.
A1 - Steers, E.
A1 - Wetzig, K.
T1 - Investigations of the emission processes in argon glow discharges containing hydrogen
T2 - Winter Conference on Plasma Spectrochemistry 2000
CY - Fort Lauderdale, FL, USA
DA - 2000-01-10
PY - 2000
SN - 0161-6951
VL - 25
SP - 302
EP - 303
PB - ICP Information Newsletter, Inc.
CY - Amherst, Mass.
AN - OPUS4-6884
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Klemm, D.
A1 - Reinholz, Uwe
A1 - Strub, E.
A1 - Röhrich, J.
A1 - Bohne, W.
A1 - Hoffmann, V.
A1 - Wetzig, K.
T1 - Potential candidates of certified reference material for determination of hydrogen concentration with glow discharge optical emission spectrometry (GD-OES) - a feasibility study
N2 - Three different coatings/layers have been found in a feasibility study as potential candidates for certified reference materials for the determination of hydrogen concentration by GD-OES: (i) electroplated zinc, (ii) carbon-rich coatings and (iii) amorphous silicon layers.
KW - CRM
KW - Hydrogen
KW - GDS
PY - 2008
DO - https://doi.org/10.1039/b717924c
SN - 0267-9477
SN - 1364-5544
VL - 23
SP - 460
EP - 462
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-17335
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ferreira da Silva, F.
A1 - do N. Varella, M. T.
A1 - Jones, N. C.
A1 - Vrönning Hoffmann, S.
A1 - Denifl, S.
A1 - Bald, Ilko
A1 - Kopyra, J.
T1 - Electron-Induced Reactions in 3-Bromopyruvic Acid
N2 - 3-Bromopyruvic acid (3BP) is a potential anticancer drug, the action of which on cellular metabolism is not yet entirely clear. The presence of a bromine atom suggests that it is also reactive towards low-energy electrons, which are produced in large quantities during tumour Radiation therapy. Detailed knowledge of the interaction of 3BP with secondary electrons is a prerequisite to gain a complete picture of the effects of 3BP in different forms of Cancer therapy. Herein, dissociative electron attachment (DEA) to 3BP in the gas phase has been studied both experimentally by using a crossed-beam setup and theoretically through scattering and quantum chemical calculations. These results are complemented by a vacuum ultraviolet absorption spectrum.
The main fragmentation channel is the formation of Br@ close to 0 eV and within several resonant features at 1.9 and 3–8 eV. At low electron energies, Br@ formation proceeds through s* and p* shape resonances, and at higher energies through core-excited resonances. It is found that the electron-capture cross-section is clearly increased compared with that of non-brominated pyruvic acid, but, at the same time, fragmentation reactions through DEA are significantly altered as well. The 3BP transient negative ion is subject to a lower number of fragmentation reactions than those of pyruvic acid, which indicates that 3BP could indeed act by modifying the electron-transport chains within oxidative phosphorylation. It could also act as a radio-sensitiser.
KW - Density functional calculations
KW - Dissociative electron attachment
KW - Drug discovery
KW - Gas-phase reactions
KW - Sensitizers
PY - 2019
DO - https://doi.org/10.1002/chem.201806132
SN - 0947-6539
VL - 25
IS - 21
SP - 5498
EP - 5506
PB - WILEY-VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-48003
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hoffmann, Katrin
T1 - Determination of Photoluminescence Quantum Yields of Semiconductor Quantum Dots with Fluorescence Correlation Spectroscopy
N2 - There is an increasing interest in bridging the gap between the photoluminescence (PL) properties of nanomaterials like semiconductor nanocrystals (QDs) commonly assessed in ensemble studies and the PL features of single QDs for life sciences applications such as bioimaging studies or use in microfluidic assays. The fluorescence quantum yield (ΦF) is a key performance parameter for all molecular and nanoscale emitters, increasingly employed in nanoscience, nanotechnology, and medical diagnostics.
ΦF determines not only the signal size together with the reporter´s molar extinction coefficient, yet it is particularly relevant for nanocrystals like QDs with coordinatively bound surface ligands and size- and surface chemistry-dependent PL characteristics.
The importance of ΦF measurements at ultralow concentration encouraged us to explore the potential of fluorescence correlation spectroscopy (FCS) for the relative determination of ΦF of ligand-stabilized CdTe nanocrystals in comparison to molecular dyes with closely matching spectral properties and known ΦF.
We describe a FCS-based method for the relative determination of ΦF of dispersed QDs at ultralow concentrations, and procedures to overcome QD-inherent challenges like complex and power-dependent blinking behavior as well as ligand- and QD-specific aggregation. We could demonstrate the potential of this approach by comparison with steady state ensemble measurements.
T2 - BIOS SPIE 2019
CY - San Francisco, CA, USA
DA - 02.02.2019
KW - Quantum yield
KW - Quantum dots
KW - FCM
PY - 2019
AN - OPUS4-47427
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hoffmann, Katrin
T1 - Calibration Beads for the Characterization of the Performance of Fluorescence-based High- Throughput and Imaging devices
N2 - In all fluorescence-based techniques, the measured signals contain not only sample-related but also instrument-specific contributions, which limit the direct comparison of fluorescence data obtained e.g. on different devices or at different times and often hamper quantification. To rule out instrumentation as major source of variability of emission data, accepted fluorescence standards and procedures for the control of instrument specifications and long-term performance are required. For flow cytometry (FCM), a broad variety of fluorophore-stained polymer beads differing in emission wavelength and intensity is available for the testing of the alignment, sensitivity, and other parameters of FCM. These calibration tools are intended to facilitate the assessment of instrument performance to ensure reliable measurements and to improve the comparability of FCM experiments.
As a step towards an improved comparability of fluorescence data, with special emphasis on spectroscopic methods measuring nano- and micrometer-sized fluorescent objects, we are currently developing a set of fluorescent polystyrene (PS) beads loaded with luminophores from the certified BAM-Kit “Spectral fluorescent standards”, initially developed for the calibration of fluorescence spectrometers. Here, we present first results from studies of these fluorophore-loaded polymer beads. Moreover, new beads are made to supplement this kit by encapsulating near-infrared (NIR)-emissive luminophores in PS beads to cover the UV/VIS, and NIR wavelength range.
These beads are designed for calibration of flow cytometers and other fluorescence imaging systems to meet the increasing demand for reliable and comparable fluorescence data especially in strongly regulated areas like e.g. medical diagnostics.
T2 - 29th Annual Conference of the German Society for Cytometry
CY - Berlin, Germany
DA - 25.09.2019
KW - Calibration beads
KW - Fluorescence
KW - Performance validation
KW - imaging
KW - FCM
PY - 2019
AN - OPUS4-49422
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rietsch, P.
A1 - Soyka, J.
A1 - Brülls, S.
A1 - Er, J.
A1 - Hoffmann, Katrin
A1 - Beerhues, J.
A1 - Sakar, B.
A1 - Resch-Genger, Ute
A1 - Eigler, S.
T1 - Fluorescence of a chiral pentaphene derivative derived from the hexabenzocoronene Motif
N2 - A new fluorescent pentaphene derivative is presented that differs
from hexabenzocoronene (HBC) by one carbon atom in the basal
plane skeleton. A 500% increased fluorescence quantum yield
is measured compared to the HBC derivative. The pentaphene
compound, obtained by a modified Scholl oxidation, is also emissive
in the solid-state, due to the packing motif in the crystal.
KW - Hexabenzocoronenes
KW - Pentaphenes
KW - Solid-state fluorescence
PY - 2019
DO - https://doi.org/10.1039/c9cc05451k
SN - 1364-548X
N1 - Corrigendum: Chemical Communications 55 (2019) 12879
VL - 55
IS - 71
SP - 10515
EP - 10518
PB - The Royal Society of Chemistry
AN - OPUS4-48908
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Hoffmann, V.
A1 - Wetzig, K.
A1 - Steers, E.B.M.
T1 - Investigations of the effect of hydrogen in an argon glow discharge
N2 - Clear evidence of the effects caused by hydrogen, introduced in different forms in an analytical glow discharge source (GDS) operated with argon, is presented for the different matrix elements copper, stainless steel, titanium, aluminium and silicon. When hydrogen is present even in small quantities in argon, not only are there significant changes in the emission line intensities of most elements (analyte and plasma species), but also new spectral features, such as emission bands of new compounds (hydrides of sputtered sample constituents) and a continuous background in the range ~220440 nm. Moreover, the discharge current (the dependent parameter in our experiments) decreases with increasing hydrogen concentration. Different modes of hydrogen introduction, externally in gaseous form or sputtered as a sample constituent, cause very similar effects in terms of discharge current, line intensity (of analyte and plasma gas) and emission continua, which implies similar changes in the discharge processes in the two cases. The excitation of the hydrogen continuum appears to quench the population of the argon metastables (11.55 and 11.72 eV) and, consequently, other elementary processes in the plasma in which the argon metastables take part, but to a different extent for each analyte.
PY - 2000
DO - https://doi.org/10.1039/b002367l
SN - 0267-9477
SN - 1364-5544
IS - 15
SP - 1075
EP - 1080
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-964
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Hoffmann, V.
A1 - Wetzig, K.
A1 - Steers, E.B.M.
T1 - Emission spectra of copper and argon in an argon glow discharge containing small quantities of hydrogen
N2 - The influence of hydrogen contained in a sample or otherwise introduced into a glow discharge source (GDS) is here extensively experimentally presented for the case of copper as a sample by means of the addition of small quantities of molecular hydrogen (<1% relative partial pressure) to the argon carrier gas. The progressive addition of molecular hydrogen causes different intensity changes particular to the individual lines of different species such as atomic (Cu I) and ionic (Cu II) copper, and also atomic (Ar I) and ionic (Ar II) argon. Some interesting features of the emission spectrum of hydrogen such as its line, band and even continuum spectrum are observed. It was also found that the depth resolution becomes worse even at very low concentrations of hydrogen.
PY - 2000
DO - https://doi.org/10.1039/b001565m
SN - 0267-9477
SN - 1364-5544
IS - 15
SP - 951
EP - 958
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-965
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geißler, Daniel
A1 - Wegmann, Marc
A1 - Jochum, T.
A1 - Somma, V.
A1 - Sowa, M.
A1 - Scholz, J.
A1 - Fröhlich, E.
A1 - Hoffmann, Katrin
A1 - Niehaus, J.
A1 - Roggenbuck, D.
A1 - Resch-Genger, Ute
T1 - An automatable platform for genotoxicity testing of nanomaterials based on the fluorometric γ-H2AX assay reveals no genotoxicity of properly surface-shielded cadmium-based quantum dots
N2 - The large number of nanomaterial-based applications emerging in the materials and life sciences and the foreseeable increasing use of these materials require methods that evaluate and characterize the toxic potential of these nanomaterials to keep safety risks to people and environment as low as possible. As nanomaterial toxicity is influenced by a variety of parameters like size, shape, chemical composition, and surface chemistry, high throughput screening (HTS) platforms are recommended for assessing cytotoxicity. Such platforms are not yet available for genotoxicity testing. Here, we present first results obtained for application-relevant nanomaterials using an automatable genotoxicity platform that relies on the quantification of the phosphorylated histone H2AX (γ-H2AX) for detecting DNA double strand breaks (DSBs) and the automated microscope system AKLIDES® for measuring integral fluorescence intensities at different excitation wavelengths. This platform is used to test the genotoxic potential of 30 nm-sized citrate-stabilized gold nanoparticles (Au-NPs) as well as micellar encapsulated iron oxide nanoparticles (FeOx-NPs) and different cadmium (Cd)-based semiconductor quantum dots (QDs), thereby also searching for positive and negative controls as reference materials. In addition, the influence of the QD shell composition on the genotoxic potential of these Cd-based QDs was studied, using CdSe cores as well as CdSe/CdS core/shell and CdSe/CdS/ZnS core/shell/shell QDs. Our results clearly revealed the genotoxicity of the Au-NPs and its absence in the FeOx-NPs. The genotoxicity of the Cd-QDs correlates with the shielding of their Cd-containing core, with the core/shell/shell architecture preventing genotoxicity risks. The fact that none of these nanomaterials showed cytotoxicity at the chosen particle concentrations in a conventional cell viability assay underlines the importance of genotoxicity studies to assess the hazardous potential of nanomaterials.
KW - Nanomaterial
KW - Genotoxicity testing
KW - γ-H2AX assay
KW - Quantum dot
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486318
DO - https://doi.org/10.1039/C9NR01021A
SN - 2040-3372
SN - 2040-3364
VL - 11
IS - 28
SP - 13458
EP - 13468
PB - The Royal Society of Chemistry
AN - OPUS4-48631
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kaufmann, Felix E.D.
A1 - Hoffmann, Marie C.
A1 - Bachmann, Kai
A1 - Veksler, Ilya V.
A1 - Trumbull, Robert B.
A1 - Hecht, Lutz
T1 - Variations in composition, texture, and platinum group element mineralization in the lower group and middle group chromitites of the Northwestern Bushveld Complex, South Africa
N2 - Small-scale variations in mineral chemistry, textures, and platinum group element (PGE) mineralization were investigated in the Lower and Middle Group chromitite layers LG6, LG6a, MG1, MG2, and MG2 II from vertical drill core profiles at the Thaba mine in the northwestern limb of the Bushveld Complex. We present detailed geochemical profiles of chromite composition and chromite crystal size distribution curves to shed light on the processes of chromite accumulation and textural modification as well as mineralization. Multiple samples within each layer were assayed for PGE concentrations, and the respective platinum group mineral association was determined by mineral liberation analysis (MLA).
There is strong evidence for postcumulus changes in the chromitites. The crystal size distribution curves suggest that the primary chromite texture was coarsened by a combination of adcumulus growth and textural equilibration, while compaction of the crystal mush played only a minor role. Mineral compositions were also modified by postcumulus processes, but because of the very high modal amount of chromite and its local preservation in orthopyroxene oikocrysts, that phase retained much primary information. Vertical variations of chromite composition within chromitite layers and from one layer to another do not support the idea of chromite accumulation from crystal-rich slurries or crystal settling from a large magma chamber. Instead, we favor a successive buildup of chromitite layers by repeated injections of relatively thin layers of chromite-saturated magmas, with in situ crystallization occurring at the crystal mush-magma interface. The adcumulus growth of chromite grains to form massive chromitite required addition of Cr to the layers, which we attribute to downward percolation from the overlying magma.
The PGE concentrations are elevated in all chromitite layers compared to adjacent silicate rocks and show a systematic increase upward from LG6 (avg 807 ppb Ir + Ru + Rh + Pt + Pd + Au) to MG2 II (avg 2,062 ppb).
There are also significant internal variations in all layers, with enrichments at hanging and/or footwalls. The enriched nature of chromitites in PGEs compared to host pyroxenites is a General feature, independent of the layer thickness. The MLA results distinguish two principal groups of PGE mineral associations: the LG6, LG6, and MG1 are dominated by the malanite series, laurite, and PGE sulfarsenides, while the MG2 and MG2 II layers are characterized by laurite and PGE sulfides as well as Pt-Fe-Sn and PGE-Sb-Bi-Pb alloys. Differences in the PGE associations are attributed to postcumulus alteration of the MG2 and MG2 II layer, while the chromitites below, particularly LG6 and LG6a, contain a more pristine association.
KW - Bushveld Complex
KW - Chromitites
KW - Platinum
PY - 2019
DO - https://doi.org/10.5382/econgeo.4641
SN - 0361-0128
VL - 114
IS - 3
SP - 569
EP - 590
PB - Society of Economic Geologists
AN - OPUS4-48145
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Carl, Peter
A1 - Sarma, Dominik
A1 - Gregório, Bruno J. R.
A1 - Hoffmann, Kristin
A1 - Lehmann, Andreas
A1 - Rurack, Knut
A1 - Schneider, Rudolf
T1 - Wash-Free Multiplexed Mix-and-Read Suspension Array Fluorescence Immunoassay for Anthropogenic Markers in Wastewater
N2 - Pharmaceuticals, certain food ingredients, and mammalian endogenous metabolic products in wastewater are mostly of human origin. They are anthropogenic markers.
Proper knowledge of their levels in wastewater helps to track sources of pollutants in natural waters and allows for calculation of removal efficiencies in wastewater Treatment plants. Here, we describe the development and application of an indirect competitive, multiplexing suspension Array fluorescence immunoassay (SAFIA) for the detection of carbamazepine (CBZ), diclofenac (DCF), caffeine (CAF), and isolithocholic acid (ILA) in wastewater, covering those classes of anthropogenic markers. The assay consists of haptens covalently conjugated to fluorescence-encoded polystyrene core/silica shell microparticles to create a site for competitive binding of the antibodies (Abs). Bound Abs are then stained with fluorophore-labeled Abs. Encoding and signaling fluorescence of the particles are determined by an automated flow cytometer.
For compatibility of the immunoassay with the 96-well microtiter plate format, a stop reagent, containing formaldehyde, is used. This enables a wash-free procedure while decreasing time-to-result. Detection limits of 140 ± 40 ng/L for CBZ, 180 ± 110 ng/L for CAF, 4 ± 3 ng/L for DCF, and 310 ± 70 ng/L for ILA are achieved, which meet the sensitivity criteria of wastewater analysis. We demonstrate the applicability of SAFIA to real wastewater samples from three different wastewater Treatment plants, finding the results in good agreement with LC-MS/MS. Moreover, the accuracy in general exceeded that from classical ELISAs. We therefore propose SAFIA as a quick and reliable approach for wastewater analysis meeting the requirements for process analytical technology.
KW - Suspension Array
KW - Immunoassay
KW - Carbamazepine
KW - Caffeine
KW - Diclofenac
KW - SAFIA
PY - 2019
DO - https://doi.org/10.1021/acs.analchem.9b03040
SN - 0003-2700
VL - 91
IS - 20
SP - 12988
EP - 12966
PB - ACS Publications
AN - OPUS4-49305
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hoffmann, Katrin
T1 - Time-resolved flow cytometry
N2 - The fast identification of a large number of analytes or events is increasingly required in bioanalytical, diagnostic, and security applications. The versatility and straightforward use make multiparametric fluorescence techniques particularly interesting as detection techniques. An established method for high-throughput single-cell and single-particle measurements is flow cytometry (FCM). Using only spectral encoding without further intensity information, state-of-the-art instruments equipped with several light sources and detectors can resolve almost 20 different color codes. However, this is not sufficient to answer complex research questions, e.g. in cell biology and immunology. In contrast, routine applications demand low-cost and sometimes even portable instruments and thus a minimum number of instrument components. Thus, there are currently two main research directions in FCM: the development of methods that can either address increasingly complex analytical challenges or provide low-cost and robust approaches for routine multiplex analyses. Common spectral multiplexing approaches face limitations in both directions. On the one hand, spectral overlap of labels restricts the number of codes and makes elaborate correction schemes necessary. On the other hand, even for lower degrees of multiplexing often a sophisticated optical setup is needed. An alternative to spectral multiplexing and intensity encoding is to exploit the luminescence lifetime (LT) as an encoding parameter. This can allow for extending the parameter space in combination with spectral encoding or result in more simple and compact devices due to fewer optical components. The availability of fast electronics enables miniaturized and portable lifetime measurement setups at relatively low cost. LT-FCM requires to master LT determination with a limited number of detected photons due to the short interaction time of the encoded objects with the laser spot. In this study, we address this issue for time-domain cytometry and present a novel lifetime flow cytometry (LT-FCM) platform based on a compact setup and straightforward time-domain measurements utilizing LT-encoded luminescent beads. Moreover, we present the realization of a first bioanalytical assay with LT-encoded beads.
T2 - ANAKON 2019
CY - Münster, Germany
DA - 25.03.2019
KW - Fluorescence
KW - Time-resolved
KW - Flow cytometry
KW - Lifetime-encoding
KW - Bead-based assays
PY - 2019
AN - OPUS4-47708
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Hoffmann, V.
A1 - Wetzig, K.
A1 - Steers, E.
T1 - ThP33 Investigations of the emission processes in argon glow discharges containing hydrogen
T2 - Winter Conference on Plasma Spectrochemistry 2000
CY - Fort Lauderdale, FL, USA
DA - 2000-01-10
PY - 2000
SN - 0161-6951
VL - 25
SP - 1
EP - 2
PB - ICP Information Newsletter, Inc.
CY - Amherst, Mass.
AN - OPUS4-846
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Obenlüneschloß, Jorit
A1 - Boysen, Nils
A1 - Rönnby, Karl
A1 - Muriqi, Arbresha
A1 - Hoffmann, Volker
A1 - Abad Andrade, Carlos Enrique
A1 - Rogalla, Detlef
A1 - Brokmann, Ulrike
A1 - Rädlein, Edda
A1 - Nolan, Michael
A1 - Devi, Anjana
T1 - Ein seltener mononuklearer Lithium‐Carben‐Komplex für die Atomlagenabscheidung von lithiumhaltigen Dünnschichten
N2 - KurzfassungLithium ist das zentrale Element moderner Batterietechnologien, und die Herstellung von lithiumhaltigen Materialien mittels Atomlagenabscheidung (engl. Atomic Layer Deposition, ALD) bietet erhebliche Vorteile bei der Kontrolle der Schichtdicke und ‐zusammensetzung. In dieser Studie wird ein neuer mononuklearer, durch ein N‐heterocyclisches Carben (NHC) stabilisierter Lithiumkomplex, [Li(tBuNHC)(hmds)], als vielversprechender Präkursor für die ALD von lithiumhaltigen Dünnschichten vorgestellt. Die strukturelle Charakterisierung erfolgt durch den Vergleich von Dichtefunktionaltheorie (DFT) und Einkristall‐Röntgenbeugung (engl. Single‐Crystal X‐ray Diffraction, SC‐XRD), wobei die seltene mononukleare Struktur bestätigt wird. Thermogravimetrische Analysen (TGA) zeigen vorteilhafte thermische Eigenschaften für ALD‐Anwendungen. Die Verbindung weist einen niedrigen Schmelzpunkt, saubere Verdampfung und ermutigende Volatilitätsparameter im Vergleich zu anderen Lithium‐Präkursoren auf. ALD‐Experimente mit [Li(tBuNHC)(hmds)] und Ozon zeigen dessen Effektivität bei der Abscheidung von LiSixOy‐Filmen. Der ALD‐Prozess zeigt ein gesättigtes Wachstum pro Zyklus (engl. Growth per Cycle, GPC) von 0,95 Å. Die Zusammensetzung, analysiert mittels Rutherford‐Rückstreu‐Spektrometrie/Kernreaktionsanalyse (engl. Rutherford Backscattering Spectrometry/Nuclear Reaction Analysis, RBS/NRA), Röntgenphotoelektronenspektroskopie (engl. X‐ray Photoelectron Spectroscopy, XPS) und Glimmentladungsspektroskopie (engl. Glow Discharge Optical Emission Spectrometry, GD‐OES), bestätigt das Vorhandensein von Lithium und Silizium in den erwarteten Verhältnissen. Diese Arbeit stellt nicht nur einen neuen ALD‐Präkursor vor, sondern trägt auch zum Verständnis der Lithiumchemie bei und bietet Einblicke in die faszinierende Koordinationschemie und das thermische Verhalten von durch NHC‐Liganden stabilisierten Lithiumkomplexen.
KW - Atomlagenabscheidung
KW - N-heterozyklischer-Carben-(NHC)-stabilisierter Lithium-Präkursor
KW - Mononuklearer Li–Carben-Komplex
KW - Lithiumsilicat-Dünnfilme
KW - Filmanalytik/-Charakterisierung
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644045
DO - https://doi.org/10.1002/ange.202513066
SN - 0044-8249
N1 - Es gibt eine parallele Sprachausgabe (englisch), ein Link befindet sich im Feld zugehöriger Identifikator - There is a parallel language edition (English), a link is in the field related identifier
SP - 1
EP - 12
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-64404
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Obenlüneschloß, Jorit
A1 - Boysen, Nils
A1 - Rönnby, Karl
A1 - Muriqi, Arbresha
A1 - Hoffmann, Volker
A1 - Abad Andrade, Carlos Enrique
A1 - Rogalla, Detlef
A1 - Brokmann, Ulrike
A1 - Rädlein, Edda
A1 - Nolan, Michael
A1 - Devi, Anjana
T1 - Rare Mononuclear Lithium-Carbene Complex for Atomic Layer Deposition of Lithium Containing Thin Films
N2 - Lithium is the core material of modern battery technologies and fabricating the lithium‐containing materials with atomic layer deposition (ALD) confers significant benefits in control of film composition and thickness. In this work, a new mononuclear N‐heterocyclic carbene (NHC) stabilized lithium complex, [Li(tBuNHC)(hmds)], is introduced as a promising precursor for ALD of lithium‐containing thin films. Structural characterization is performed, comparing density functional theory (DFT) and single‐crystal X‐ray diffraction (SC‐XRD), confirming a rare mononuclear structure. Favorable thermal properties for ALD applications are evidenced by thermogravimetric analysis (TGA). The compound exhibits a low melting point, clean evaporation, and its volatility parameters are encouraging compared to other lithium precursors. ALD trials using [Li(tBuNHC)(hmds)] with ozone demonstrate its effectiveness in depositing LiSixOy films. The ALD process exhibits a saturated growth per cycle (GPC) of 0.95 Å. Compositional analysis using Rutherford backscattering spectrometry/nuclear reaction analysis (RBS/NRA), X‐ray photoelectron spectrometry (XPS), and glow discharge optical emission spectrometry (GD‐OES), confirms the presence of lithium and silicon in the expected ratios. This work not only presents a new ALD precursor but also contributes to the understanding of lithium chemistry, offering insights into the intriguing coordination chemistry and thermal behavior of lithium complexes stabilized by NHC ligands.
KW - Atomic layer deposition (ALD)
KW - N-heterocyclic carbene (NHC) ligands
KW - Lithium ALD precursor chemistry
KW - Mononuclear Li–carbene complex [Li(tBuNHC)(hmds)]
KW - Li-silicate thin films (LiSixOy)
KW - Thermal properties & TGA/volatility
KW - Compositional analysis (RBS/NRA, XPS, GD-OES)
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643790
DO - https://doi.org/10.1002/anie.202513066
SN - 1433-7851
N1 - Es gibt eine parallele Sprachausgabe (deutsch), ein Link befindet sich im Feld zugehöriger Identifikator - There is a parallel language edition (German), a link is in the field related identifier
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-64379
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Sittner, Jonathan
A1 - Hoffmann, T.
A1 - Bertmer, M.
A1 - Neubert, M.
A1 - Schuster, T.
A1 - Gluth, Gregor
ED - D’Erme, C.
ED - Paglia, C.
ED - Cordero, E. G.
T1 - Influence of the calcination method on the transformations and the reactivity of calcined low-kaolinitic clays
N2 - This study investigates the calcination of low-grade kaolinitic clays containing high proportions of 2:1 clay minerals using two different methods: rotary kiln and fluidized bed calcination. The objective was to evaluate their potential as supplementary cementitious materials. The results demonstrate that even clays with low kaolinite content, when processed in a rotary kiln, exhibit pozzolanic properties suitable for cement replacement. Furthermore, fluidized bed calcination proved to be an energy-efficient alternative, achieving considerable dehydroxylation within just 30 min of calcination. This indicates the potential for substantial energy savings compared to conventional calcination techniques. However, further optimization of the process conditions is required to maximize reactivity and industrial applicability. The findings contribute to the ongoing development of sustainable cementitious materials by utilizing widely available, 2:1 clay mineral-dominated resources.
KW - Calcined clay
KW - Supplementary cementitous materials
KW - Blended cement
KW - Fluidized bed
PY - 2026
SN - 978-3-032-14166-8
DO - https://doi.org/10.1007/978-3-032-14166-8_28
VL - 2
SP - 280
EP - 289
PB - Springer
CY - Cham
AN - OPUS4-65377
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoffmann, H
A1 - Paulisch, M C
A1 - Gebhard, M
A1 - Osiewacz, J
A1 - Kutter, M
A1 - Hilger, A
A1 - Arlt, T
A1 - Kardjilov, N
A1 - Ellendorff, B
A1 - Beckmann, F
A1 - Markötter, Henning
A1 - Luik, M
A1 - Turek, T
A1 - Manke, I
A1 - Roth, C
T1 - Development of a Modular Operando Cell for X-ray Imaging of Strongly Absorbing Silver-Based Gas Diffusion Electrodes
N2 - Metal-based gas diffusion electrodes are utilized in chlor-alkali electrolysis or electrochemical reduction of carbon dioxide, allowing the reaction to proceed at high current densities. In contrast to planar electrodes and predominantly 2D designs, the industrially required high current densities can be achieved by intense contact between the gas and liquid phase with the catalytically active surfaces. An essential asset for the knowledge-based design of tailored electrodes is therefore in-depth information on electrolyte distribution and intrusion into the electrode’s porous structure. Lab-based and synchrotron radiography allow for monitoring this process operando. Herein, we describe the development of a cell design that can be modularly adapted and successfully used to monitor both the oxygen reduction reaction and the electrochemical reduction of CO2 as exemplary and currently very relevant examples of gas-liquid reactions by only minor modifications to the cell set-up. With the reported cell design, we were able to observe the electrolyte distribution within the gas diffusion electrode during cell operation in realistic
conditions.
KW - X-Ray imaging
KW - Gas diffusion electrodes
KW - Operando cell
PY - 2022
DO - https://doi.org/10.1149/1945-7111/ac6220
VL - 169
IS - 4
SP - 044508
PB - IOP science
AN - OPUS4-55027
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hoffmann, V.
T1 - Tiefenprofilanalytik mittels Glimmentladungsspektrometrie von nichtleitenden Schichtsystemen
T2 - AOFA12
CY - Kaiserslautern, Germany
DA - 2002-09-15
PY - 2002
AN - OPUS4-6242
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Hoffmann, V.
A1 - Steers, E.B.M.
A1 - Griepentrog, Michael
A1 - Dück, Alexander
A1 - Beck, Uwe
T1 - Round Robin exercise: Coated materials for glow discharge spectroscopy
N2 - A Round Robin (RR) exercise on selected coated materials has been carried out with the aim of finding the optimal conditions for the analysis of nitride layers with GD-OES. Such pre-normative work is necessary for the evaluation of parallel development of the production of nitride layers as certified reference materials (CRMs). Two types of samples, TiN layer and VN layer, respectively, with chemical compositions close to stoichiometry and a thickness of ~3 µm, deposited on a steel substrate, have been provided to the RR participants. Additionally, another type of sample, a (100 nm CrNi/100 nm Cu) multilayer (ML) stack deposited on silicon wafer has also been included in the RR. This sample can be used as a CRM for checking GD spectrometer conditions and it has been proved helpful in further development of GDS instrumentation and methodology. The RR exercise has been performed in the frame of the EC Thematic Network on Glow Discharge Spectroscopy for Spectrochemical Analysis (GDS-Net).
KW - Coated/Layered Reference Materials
KW - Nitrides
KW - Multilayer
KW - GDS
KW - Round Robin
PY - 2006
DO - https://doi.org/10.1039/B513426A
SN - 0267-9477
SN - 1364-5544
VL - 21
IS - 1
SP - 74
EP - 81
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-11762
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Unger, Wolfgang
A1 - Jenett, H.
A1 - Hoffmann, V.
A1 - Hagenhoff, B.
A1 - Kayser, S.
A1 - Wetzig, K.
T1 - Depth profiling of electrically non-conductive layered samples by RF-GDOES and HFM plasma SNMS
N2 - The work is intended to compare the capabilities of two similar depth profiling techniques to analyse electrically non-conductive samples. In order to get a better evaluation of the depth resolution, various multilayer sandwiches, such as SiO2/TiO2 and Si3N4/SiO2 deposited on glass substrates have been investigated. Optimised depth profiles are presented for both methods, glow discharge optical emission spectrometry (GDOES) and radiofrequency mode (known as HFM in the SNMS literature) of plasma secondary neutral mass spectrometry (SNMS). The optimisation procedure, necessary to get the best set of plasma parameters, which result in the optimal depth resolution, is also described for one selected sample. Additionally, sputtering crater profilometry was carried out in order to check out the flatness of the sputtered crater. The influence of the thickness of the sample substrate on the sputtering rate is discussed. Finally, advantages and disadvantages of the use of these two depth profiling methods, especially for the non-conductive samples, are concluded from this comparative study. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of a cross-sectioned sample was carried out in order to get supplementary information.
KW - rf-Glow discharge
KW - HFM plasma SNMS
KW - Non-conductive layered samples
KW - Depth resolution
KW - Crater shape
KW - ToF-SIMS
PY - 2001
DO - https://doi.org/10.1016/S0169-4332(01)00259-8
SN - 0169-4332
SN - 1873-5584
VL - 179
IS - 1-4
SP - 30
EP - 37
PB - North-Holland
CY - Amsterdam
AN - OPUS4-6882
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Hoffmann, V.
A1 - Steers, E. B. M.
A1 - Wetzig, K.
T1 - Exploitation of the effect of hydrogen on an analytical glow discharge
T2 - Winter Conference on Plasma Spectrochemistry 2002
CY - Scottsdale, AZ, USA
DA - 2002-01-06
PY - 2002
SN - 0161-6951
SP - 261
EP - 262
PB - ICP Information Newsletter, Inc.
CY - Amherst, Mass.
AN - OPUS4-1589
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bruna, F. G.
A1 - Prokop, M.
A1 - Bystron, T.
A1 - Loukrakpam, R.
A1 - Melke, J.
A1 - Lobo, C. M. S.
A1 - Fink, M.
A1 - Zhu, M.
A1 - Voloshina, E.
A1 - Kutter, M.
A1 - Hoffmann, H.
A1 - Yusenko, Kirill
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Röder, B.
A1 - Bouzek, K.
A1 - Paulus, B.
A1 - Roth, C.
T1 - Following adsorbed intermediates on a platinum gas diffusion electrode in H3PO3‑containing electrolytes using in situ X‑ray absorption spectroscopy
N2 - One of the challenges of high-temperature polymer electrolyte membrane fuel cells is the poisoning of the Pt catalyst with H3PO4. H3PO4 is imbibed into the routinely used polybenzimidazole-based membranes, which facilitate proton conductivity in the temperature range of 120−200 °C. However, when leached out of the membrane by water produced during operation, H3PO4 adsorbs on the Pt catalyst surface, blocking the active sites and hindering the oxygen reduction reaction (ORR).
The reduction of H3PO4 to H3PO3, which occurs at the anode due to a combination of a low potential and the presence of gaseous H2, has been investigated as an additional important contributing factor to the observed poisoning effect. H3PO3 has an affinity toward adsorption on Pt surfaces even greater than that of H2PO4 −. In this work, we investigated the poisoning effect of both H3PO3 and H3PO4 using a half-cell setup with a gas diffusion electrode under ambient conditions. By means of in situ X-ray absorption spectroscopy, it was possible to follow the signature of different species adsorbed on the Pt nanoparticle catalyst (H, O, H2PO4 −, and H3PO3) at different potentials under ORR conditions in various electrolytes (HClO4, H3PO4, and H3PO3). It was found that H3PO3 adsorbs in a pyramidal configuration P(OH)3 through a Pt−P bond. The competition between H3PO4 and H3PO3 adsorption was studied, which should allow for a better understanding of the catalyst poisoning mechanism and thus assist in the development of strategies to mitigate this phenomenon in the future by minimizing H3PO3 generation by, for example, improved catalyst design or adapted operation conditions or changes in the electrolyte composition.
KW - H3PO4 life cycle
KW - XAS
KW - In situ coupling
KW - High-temperature fuel cells
KW - Δμ XANES
KW - H3PO3
PY - 2022
DO - https://doi.org/10.1021/acscatal.2c02630
SN - 2155-5435
VL - 12
IS - 18
SP - 11472
EP - 11484
PB - ACS
CY - Washington, DC
AN - OPUS4-55815
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sittner, Jonathan
A1 - Hoffmann, T.
A1 - Bertmer, M.
A1 - Neubert, M.
A1 - Schuster, T.
A1 - Gluth, Gregor
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Optimizing calcination methods towards a more sustainable production of calcined clays
N2 - Calcined clays are emerging as sustainable alternatives for cement production due to their potential to reduce carbon footprint and energy consumption. This study investigates the calcination of low-grade kaolinitic clays, using rotary kiln and fluidized bed. The calcined clays from the rotary kiln showed enhanced performance in the cement paste. The fluidized bed method demonstrated the potential for significant energy savings, achieving near-complete dehydroxylation with just 30 minutes of calcination. These findings highlight the promise of fluidized bed calcination for efficient clay activation, though further optimization is needed.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Calcination methods
KW - Optimizing
KW - Blended cement pastes
KW - XRD results
KW - Thermogravimetric analysis (TGA)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612891
SN - 978-3-9818564-7-7
SP - 37
EP - 45
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61289
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Glauber, J.-P.
A1 - Lorenz, J.
A1 - Liu, J.
A1 - Seifert, M.
A1 - Hoffmann, V.
A1 - Abad Andrade, Carlos Enrique
A1 - Rogalla, D.
A1 - Harms, C.
A1 - Wark, M.
A1 - Nolan, M.
A1 - Devi, A.
T1 - High Quality Crystalline VN Thin Films via MOCVD from a New Vanadium Precursor: Linking Growth Chemistry to Functional Catalytic Surfaces
N2 - Vanadium nitride (VN) has been identified as a promising material for numerous applications including electrochemical nitrogen reduction reaction (eNRR). For such applications, catalyst nanoengineering will help to experimentally test its theoretically predicted eNRR activity, but the majority of investigated VN catalysts are prepared by fabrication methods that do not allow for nanoengineering to the required degree. Herein, we report on a new metalorganic chemical vapor deposition (MOCVD) process for the growth of high quality, facetted and crystalline VN thin films relevant for eNRR applications. N,N’-diisopropylformamidinato [V(dpfamd)3] was identified as a promising precursor as it possesses favorable thermal properties relevant for MOCVD. The application of [V(dpfamd)3] in a MOCVD process with NH3 as co-reactant yielded crystalline VN thin films on Si substrates with high compositional purity. With the potential of using the catalytic activity of VN towards eNRR, the structure-property correlation is of relevance and in this context, the thin films were subjected to complementary analysis including X-ray diffraction (XRD), Rutherford backscattering spectrometry in combination with nuclear reaction analysis (RBS/NRA), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Based on the observation of the significant influence NH3 has on the growth characteristics, we conducted first principles density functional theory (DFT) simulations of the precursor reactivity in the absence and presence of NH3 towards VN, supporting experimental findings of energetically more favorable decomposition of [V(dpfamd)3] to VN in the presence of NH3. Process transfer from Si to conductive Ti substrates, relevant for prospective electrochemical testing, revealed comparable VN thin film properties rendering these films promising for further investigation of eNRR applications in follow up studies.
KW - Metal nitrades
KW - MOCVD
KW - Nitrogen reduction reaction
KW - Precursors
KW - DFT
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648600
DO - https://doi.org/10.26434/chemrxiv-2025-1t4gq
SP - 1
EP - 25
AN - OPUS4-64860
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weimann, Karin
A1 - Hoffmann, C.
T1 - Ressourceneffizienz im Betonrecycling - Rahmen und Möglichkeiten in Deutschland und der Schweiz
N2 - Aufgrund der großen anfallenden Massenströme ist die Wiederverwertung von Baurestmassen in Industrienationen von besonderer Bedeutung. Auch vor dem Hintergrund der Ressourceneffizienz wird beispielsweise die Nutzung des in Bauschutt vorhandenen Wertstoffpotentials zunehmend wichtiger.
Eine besondere Rolle spielt dabei die Wiederverwertung von Altbeton. Ein Grund hierfür ist der deutliche Anstieg des seit Mitte des letzten Jahrhunderts im Bauwesen verbrauchten Betons und die damit verbundene – zeitlich versetzte – Zunahme des Altbetonanteils im Bauschutt. Darüber hinaus ist das Wertstoffpotential von Altbeton im Vergleich zu anderen Abbruchmaterialien besonders groß, denn Altbeton kann unter bestimmten Bedingungen sehr hochwertig auch als rezyklierte Gesteinskörnung wieder in der Betonherstellung eingesetzt werden. Damit kann ein Kreislauf im Sinne eines Closed-loop-Recycling verwirklicht und Altbeton damit hochwertig wiederverwertet werden.
T2 - R13 - Fachtagung Recycling
CY - Weimar, Germany
DA - 19.09.2013
KW - Ressourceneffizienz
KW - Beton
KW - Recycling
KW - Ökobilanzielle Betrachtung
PY - 2013
IS - Paper 14
SP - 1
EP - 11
PB - Bauhaus-Univ.
CY - Weimar
AN - OPUS4-30061
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gomes, Bruna F.
A1 - Prokop, Martin
A1 - Bystron, Tomas
A1 - Loukrakpam, Rameshwori
A1 - Melke, Julia
A1 - Lobo, Carlos M. S.
A1 - Fink, Michael
A1 - Zhu, Mengshu
A1 - Voloshina, Elena
A1 - Kutter, Maximilian
A1 - Hoffmann, Hendrik
A1 - Yusenko, Kirill V.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Röder, Bettina
A1 - Bouzek, Karel
A1 - Paulus, Beate
A1 - Roth, Christina
T1 - Following Adsorbed Intermediates on a Platinum Gas Diffusion Electrode in H3PO3-Containing Electrolytes Using In Situ X-ray Absorption Spectroscopy
N2 - One of the challenges of high-temperature polymer electrolyte membrane fuel cells is the poisoning of the Pt catalystwith H3PO4. H3PO4 is imbibed into the routinely used polybenzimidazole-based membranes, which facilitate Proton conductivity in the temperature range of 120−200 °C. However, when leached out of the membrane by water produced during operation, H3PO4 adsorbs on the Pt catalyst surface, blocking the active sites and hindering the oxygen reduction reaction (ORR).
The reduction of H3PO4 to H3PO3, which occurs at the anode due to a combination of a low potential and the presence of gaseous H2, has been investigated as an additional important contributing factor to the observed poisoning effect. H3PO3 has an affinity toward adsorption on Pt surfaces even greater than that of H2PO4 −. In this work, we investigated the poisoning effect of both H3PO3 and H3PO4 using a half-cell setup with a gas diffusion electrode under ambient conditions. By means of in situ X-ray absorption spectroscopy, it was possible to follow the signature of different species adsorbed on the Pt nanoparticle catalyst (H, O, H2PO4 −, and H3PO3) at different potentials under ORR conditions in various electrolytes (HClO4, H3PO4, and H3PO3). It was found that H3PO3 adsorbs in a pyramidal configuration P(OH)3 through a Pt−P bond. The competition between H3PO4 and H3PO3 adsorption was studied, which should allow for a better understanding of the catalyst poisoning mechanism and thus assist in the development of strategies to mitigate this phenomenon in the future by minimizing H3PO3 generation by, for example, improved catalyst design or adapted operation conditions or changes in the electrolyte composition.
KW - H3PO4 life cycle
KW - XAS
KW - In situ coupling
KW - High-temperature fuel cells
KW - H3PO3,
KW - Δμ XANES
PY - 2022
DO - https://doi.org/10.1021/acscatal.2c02630
SN - 2155-5435
VL - 12
IS - 18
SP - 11472
EP - 11484
PB - American Chemical Society (ACS)
AN - OPUS4-64733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bui, M.
A1 - Hoffmann, K. F.
A1 - Braun, T.
A1 - Riedel, S.
A1 - Heinekamp, Christian
A1 - Scheurell, K.
A1 - Scholz, G.
A1 - Stawski, Tomasz
A1 - Emmerling, Franziska
T1 - An Amorphous Teflate Doped Aluminium Chlorofluoride:
A Solid Lewis-Superacid for the Dehydrofluorination of
Fluoroalkanes
N2 - Ananion-dopedaluminiumchlorofluoride AlCl0.1F2.8(OTeF5)0.1(ACF-teflate) was synthesized.The material contains pentafluor-oorthotellurate(teflate)groups, which mimic fluoride ions electronically, but are sterically more demanding. They are embedded into the amorphous structure. The latter was studied by PDF analysis, EXAFS data and MAS NMR spectroscopy. The mesoporous powder is a Lewis superacid, and ATR-IR spectra of adsorbed CD3CN reveal a blue-shift of the adsorption band by73 cm-1, which is larger than the shift for SbF5. Remarkably,ACF-teflate catalyzes dehydrofluorination reactions of mono-fluoroalkanes to yield olefins in C6D6. In these cases,no Friedel-Crafts products were formed.
KW - Aluminium fluorides
KW - Aluminium teflates
KW - C-F bond activation
KW - Lewis superacids
KW - Silanes
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572290
DO - https://doi.org/10.1002/cctc.202300350
SN - 1867-3880
SP - 1
EP - 7
PB - Wiley VHC-Verlag
AN - OPUS4-57229
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abbas, Ioana M.
A1 - Vranic, M.
A1 - Hoffmann, Holger
A1 - El-Khatib, Ahmed H.
A1 - Montes-Bayón, M.
A1 - Möller, H. M.
A1 - Weller, Michael G.
T1 - Investigations of the copper peptide hepcidin-25 by LC-MS/MS and NMR (+)
N2 - Hepcidin-25 was identified as the main iron regulator in the human body, and it by binds to the sole iron-exporter ferroportin. Studies showed that the N-terminus of hepcidin is responsible for this interaction, the same N-terminus that encompasses a small copper(II)-binding site known as the ATCUN (amino-terminal Cu(II)- and Ni(II)-binding) motif. Interestingly, this copper-binding property is largely ignored in most papers dealing with hepcidin-25. In this context, detailed investigations of the complex formed between hepcidin-25 and copper could reveal insight into its biological role. The present work focuses on metal-bound hepcidin-25 that can be considered the biologically active form. The first part is devoted to the reversed-phase chromatographic separation of copper-bound and copper-free hepcidin-25 achieved by applying basic mobile phases containing 0.1% ammonia. Further, mass spectrometry (tandem mass spectrometry (MS/MS), high-resolution mass spectrometry HRMS)) and nuclear magnetic resonance (NMR) spectroscopy were employed to characterize the copper-peptide. Lastly, a three-dimensional (3D)model of hepcidin-25with bound copper(II) is presented. The identification of metal complexes and potential isoforms and isomers, from which the latter usually are left undetected by mass spectrometry, led to the conclusion that complementary analytical methods are needed to characterize a peptide calibrant or reference material comprehensively. Quantitative nuclear magnetic resonance (qNMR), inductively-coupled plasma mass spectrometry (ICP-MS), ion-mobility spectrometry (IMS) and chiral amino acid analysis (AAA) should be considered among others.
KW - Metalloprotein
KW - Peptide
KW - Chromatography
KW - High pH
KW - Mobile phase
KW - Metrology
KW - Purity
KW - Reference material
KW - ATCUN
KW - Copper
KW - Nickel
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457796
UR - http://www.mdpi.com/1422-0067/19/8/2271
DO - https://doi.org/10.3390/ijms19082271
SN - 1422-0067
VL - 19
IS - 8
SP - 2271, 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-45779
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abbas, Ioana M.
A1 - Hoffmann, Holger
A1 - Montes-Bayón, M.
A1 - Weller, Michael G.
T1 - Improved LC-MS/MS method for the quantification of hepcidin-25 in clinical samples
N2 - Mass spectrometry-based methods play a crucial role in the quantification of the main iron metabolism regulator hepcidin by singling out the bioactive 25-residue peptide from the other naturally occurring N-truncated isoforms (hepcidin-20, -22, -24), which seem to be inactive in iron homeostasis. However, several difficulties arise in the MS analysis of hepcidin due to the sticky character of the peptide and the lack of suitable standards. Here, we propose the use of amino- and fluoro-silanized autosampler vials to reduce hepcidin interaction to laboratory glassware surfaces after testing several types of vials for the preparation of stock solutions and serum samples for isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS). Furthermore, we have investigated two sample preparation strategies and two chromatographic separation conditions with the aim of developing an LC-MS/MS method for the sensitive and reliable quantification of hepcidin-25 in serum samples. A chromatographic separation based on usual acidic mobile phases was compared with a novel approach involving the separation of hepcidin-25 with solvents at high pH containing 0.1% of ammonia. Both methods were applied to clinical samples in an intra-laboratory comparison of two LC-MS/MS methods using the same hepcidin-25 calibrators with good correlation of the results. Finally, we recommend an LC-MS/MS-based quantification method with a dynamic range of 0.5–40 μg/L for the assessment of hepcidin-25 in human serum that uses TFA-based mobile phases and silanized glass vials.
KW - HPLC
KW - Liquid chromatography
KW - Mass spectrometry
KW - Silanization
KW - Mobile phase
KW - Adsorption
KW - Peptide losses
KW - Recovery
KW - Validation
KW - Quality control
KW - QC
KW - Iron disorders
KW - Chronic kidney disease
KW - Metrology
KW - Round robin exercise
KW - Basic solvent
KW - Peptide analysis
PY - 2018
DO - https://doi.org/10.1007/s00216-018-1056-0
SN - 1618-2642
SN - 1618-2650
VL - 410
IS - 16
SP - 3835
EP - 3846
PB - Springer Nature
CY - Heidelberg
AN - OPUS4-45053
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Descalzo López, Ana Belén
A1 - Xu, H.-J.
A1 - Xue, Z.-L.
A1 - Hoffmann, Katrin
A1 - Shen, Z.
A1 - Weller, Michael G.
A1 - You, X.-Z.
A1 - Rurack, Knut
T1 - Phenanthrene-Fused Boron-Dipyrromethenes as Bright Long-Wavelength Fluorophores
N2 - A new class of boron-dipyrromethene (BDP or BODIPY) dyes was obtained by phenanthrene fusion to the β-pyrrole positions, absorbing in the wavelength range of important laser sources. Despite a 'propeller-like' distorted structure in the crystalline state, the chromophore absorbs (log ε ≥ 5) and fluoresces (Φf ≥ 0.8) strongly and can be easily turned into a fluorescence light-up probe. Incorporation into latex beads produces bright and photostable single-dye and Förster Resonance Energy Transfer (FRET) particles for microscopy applications.
KW - Fluoreszenz
KW - Absorption
KW - BODIPY-Farbstoffe
KW - Ladungstransfer
KW - NIR-Farbstoffe
PY - 2008
DO - https://doi.org/10.1021/ol800271e
SN - 1523-7060
SN - 1523-7052
VL - 10
IS - 8
SP - 1581
EP - 1584
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-17511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiesner, Yosri
A1 - Hoffmann, Thomas
A1 - Range, David
A1 - Altmann, Korinna
T1 - Microplastics in sediments of the river Rhine—A workflow for preparation and analysis of sediment samples from aquatic river systems for monitoring purposes
N2 - AbstractMicroplastics (MP) can be detected in all environmental systems. Marine and terrestrial aquatic systems, especially the transported suspended solids, have often been the focus of scientific investigations in the past. Sediments of aquatic river systems, on the other hand, were often ignored due to the time‐consuming sample preparation and analysis procedures. Spectroscopic measurement methods counting particle numbers are hardly suitable as detection methods, because there are plenty of natural particles next to a small number of MP particles. Integral methods, such as thermoanalytical methods are determining the particle mass independently of the inorganic components.In this study, a workflow for sample preparation via density separation and subsequent analysis by thermal extraction desorption‐gas chromatography/mass spectrometry is presented, which leads to representative and homogeneous samples and allows fast and robust MP mass content measurements suitable for routine analysis. Polymers were identified and quantified in all samples. Polyethylene and styrene‐butadiene rubber are the dominant polymers, besides polypropylene and polystyrene. Overall, total polymer masses between 1.18 and 337.0 µg/g could be determined. Highest MP concentrations in riverbed sediment are found in sites characterized by low flow velocities in harbors and reservoirs, while MP concentrations in sandy/gravelly bed sediments with higher flow velocities are small.
KW - Microplastics
KW - Density separation
KW - TED-GC/MS
KW - NaI
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597335
DO - https://doi.org/10.1002/appl.202200125
VL - 3
IS - 2
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-59733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -