TY - JOUR A1 - Seeger, Stefan A1 - Osan, J. A1 - Czömpöly, O. A1 - Gross, A. A1 - Stosnach, H. A1 - Stabile, L. A1 - Ochsenkuehn-Petropoulou, M. A1 - Tsakanika, L. A1 - Lymperopoulou, T. A1 - Goddard, S. A1 - Fiebig, M. A1 - Gaie-Levrel, F. A1 - Kayser, Y. A1 - Beckhoff, B. T1 - Quantification of Element Mass Concentrations in Ambient Aerosols by Combination of Cascade Impactor Sampling and Mobile Total Reflection X-ray Fluorescence Spectroscopy N2 - Quantitative chemical analysis of airborne particulate matter (PM) is vital for the understanding of health effects in indoor and outdoor environments, as well as for enforcing EU air quality regulations. Typically, airborne particles are sampled over long time periods on filters, followed by lab-based analysis, e.g., with inductively coupled plasma mass spectrometry (ICP-MS). During the EURAMET EMPIR AEROMET project, cascade impactor aerosol sampling is combined for the first time with on-site total reflection X-ray fluorescence (TXRF) spectroscopy to develop a tool for quantifying particle element compositions within short time intervals and even on-site. This makes variations of aerosol chemistry observable with time resolution only a few hours and with good size resolution in the PM10 range. The study investigates the proof of principles of this methodological approach. Acrylic discs and silicon wafers are shown to be suitable impactor carriers with sufficiently smooth and clean surfaces, and a non-destructive elemental mass concentration measurement with a lower limit of detection around 10 pg/m3 could be achieved. We demonstrate the traceability of field TXRF measurements to a radiometrically calibrated TXRF reference, and the results from both analytical methods correspond satisfactorily. KW - TXRF KW - Reference method KW - Cascade impactor KW - Ambient aerosols KW - Particles KW - Air quality monitoring KW - Element mass concentration KW - Size resolved chemical composition KW - Time resolved chemical composition KW - ICP-MS PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521860 UR - http://www.aerometproject.com/ DO - https://doi.org/10.3390/atmos12030309 SN - 2073-4433 VL - 12 IS - 3 SP - 309 EP - 337 PB - MDPI CY - Basel, Schweiz AN - OPUS4-52186 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Julsing, M.K. A1 - Fichera, Mario Augusto A1 - Malz, Frank A1 - Ebbelaar, M. A1 - Bos, R. A1 - Woerdenbag, H. J. A1 - Quax, W.J. A1 - Kayser, O. T1 - Bioconversion of Mono- and Sesquiterpenoids by recombinant human Cytochrome P450 Monooxygenases N2 - Cytochrome P450 monooxygenases play an important role in the biosynthesis and metabolism of terpenoids. We explored the potential of recombinant human liver cytochrome P450 monooxygenases CYP1A2, CYP2C9, and CYP3A4, heterologously expressed in Escherichia coli, to convert mono- and sesquiterpenoids to human metabolites. This natural product group is a diverse class of secondary metabolites and includes several industrially and pharmaceutically interesting compounds. Incubation of cedrol with CYP3A4 resulted in a bioconversion of 74% (±8.9%) after 1 h of the unknown metabolites 2-hydroxycedrol and 4-hydroxycedrol, which have been structurally elucidated by 1H and 13C NMR and GC-MS. We conclude that recombinant human cytochrome P450 enzymes can be useful tools in a combinatorial biosynthesis strategy for the production of new natural products and for in vitro metabolization studies. KW - Cedrol KW - Cytochrome P450 KW - Drug metabolism KW - NMR KW - Terpenoids PY - 2008 DO - https://doi.org/10.1080/13880200802215487 SN - 1388-0209 SN - 1744-5116 VL - 46 IS - 10-11 SP - 710 EP - 718 PB - Informa Healthcare CY - New York, NY, USA AN - OPUS4-18912 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -