TY - JOUR A1 - Scharkoi, O. A1 - Esslinger, Susanne A1 - Becker, Roland A1 - Weber, M. A1 - Nehls, Irene T1 - Phase I oxidation of alpha- and gamma-hexabromocyclododecane by cytochrome P450 enzymes: simulation of the steroisomerism of hydroxylated metabolites T2 - DIOXIN 2011 CY - Brussels, Belgium DA - 2011-08-21 KW - Bromierte Falmmschutzmittel KW - Hexabromcyclododecan KW - Cytochrom KW - Metaboliten KW - HPLC KW - Simulation PY - 2011 UR - http://www.dioxin20xx.org/pdfs/2011/1810.pdf SN - 1026-4892 VL - 73 SP - 730 EP - 733 AN - OPUS4-27263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reck, Günter A1 - Becker, Roland T1 - Phenanthroline complexes of zinc and calcium carbamates N2 - Bis(N,N-di-n-butyl­di­thio­carbamato-?2S,S')(1,10-phenanthroline-?2N,N')­zinc(II) ethanol hemisolvate, [Zn(C9H18NS2)2(C12H8N2)]·0.5C2H6O, (I), and bis(N,N-di-n-hexyldithiocarbamato-?2S,S')­bis(1,10-phenanthroline-?2N,N')calcium(II), [Ca(C13H26NS2)2(C12H8N2)2], (II), are mixed-ligand com­plexes. In the first compound, the Zn atom has a distorted octahedral coordination, while in the second compound, the Ca atom is eight-coordinate, with four S and four N atoms forming a highly distorted cube. KW - X-ray structure analyses KW - Metal-organic complexes KW - Antioxidant properties PY - 2004 DO - https://doi.org/10.1107/S0108270104001441 SN - 0108-2701 SN - 1600-5759 VL - 60 SP - m134 EP - m136 PB - Blackwell Publ. CY - Oxford AN - OPUS4-3110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sichler, Theresa Constanze A1 - Adam, Christian A1 - Becker, Roland A1 - Sauer, Andreas A1 - Ostermann, Markus A1 - Barjenbruch, M. T1 - Phosphorus determination in sewage sludge: comparison of different aqua regia digestion methods and ICP-OES, ICP-MS and photometric determination N2 - Phosphorus recycling from sewage sludge will be obligatory in Germany from 2029. Phosphorus content determination in sewage sludge is crucial to assess the prescribed recycling rates. Currently, German law regards sample preparation using aqua regia digestion in a microwave or under reflux conditions as well as instrumental phosphorus determination by ICP-OES, ICP-MS, or photometric determination with ammonium molybdate as equivalent. However, it is questionable whether these methods are indeed equivalent regarding phosphorus quantification in sludges near the limit of 20 g/kg for mandatory recycling. To answer this question, 15 sewage sludges of 11 different wastewater treatment plants were investigated with all permitted method (digestion and measurement) combinations. Moreover, one sewage sludge was also examined in an interlaboratory comparison (ILC) with 28 participants. This study shows that the above-mentioned methods differ in some cases significantly but across all method combinations and sludges, phosphorus recovery was between 80 and 121% after normalization to the grand mean (average of 15 sludges between 85 and 111%). The ILC and the examination of 15 sludges produced largely similar results. There is a tendency to higher phosphorus recovery after microwave digestion compared to reflux digestion and ICP-OES measurements determine higher phosphorus contents than ICP-MS and photometric phosphorus determination. As a result, the authors recommend ICP-OES determination of phosphorus in sewage sludge after microwave digestion. KW - Sewage sludge KW - ICP-OES KW - Phosphous recovery KW - ICP-MS KW - Photometric P determination KW - Interlaboratory comparison PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558869 DO - https://doi.org/10.1186/s12302-022-00677-1 VL - 34 IS - 99 SP - 1 EP - 14 PB - Springer AN - OPUS4-55886 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scharkoi, O. A1 - Becker, Roland A1 - Esslinger, Susanne A1 - Weber, M. A1 - Nehls, Irene T1 - Predicting sites of cytochrome P450-mediated hydroxylation applied to CYP3A4 and hexabromocyclododecane N2 - This article describes a simple and quick in silico method for the prediction of cytochrome P450 (CYP)-mediated hydroxylation of drug-like compounds. Testosterone and progesterone, two known substrates of CYP3A4, are used to test the method. Further, we apply the procedure to predict sites of hydroxylation of isomers of the flame retardant hexabromocyclododecane by CYP3A4. Within the method, the compound is rotated in the binding pocket of the cytochrome, so that each hydrogen under consideration is placed near the active centre. Afterwards, short molecular dynamics simulations are provided for each step of the rotation. All steps of the simulation are compared concerning the distances between the hydrogens and the active centre and the corresponding energies. The computational results correlate well with experimental results. KW - Predicting sites of metabolism KW - Cytochrome P450 KW - Hydroxylation KW - Metabolism of HBCD PY - 2015 DO - https://doi.org/10.1080/08927022.2014.898845 SN - 0892-7022 SN - 1029-0435 VL - 41 IS - 7 SP - 538 EP - 546 PB - Gordon and Breach CY - New York, NY AN - OPUS4-30492 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Riddell, N. A1 - Becker, Roland A1 - Chittim, B. A1 - Emmerling, Franziska A1 - Köppen, Robert A1 - Lough, A. A1 - McAlees, A. A1 - McCrindle, R. T1 - Preparation and X-ray structural characterization of further stereoisomers of 1,2,5,6,9,10-hexabromocyclododecane N2 - Technical 1,2,5,6,9,10-hexabromocyclododecane (HBCD) consists largely of three diastereomers (α-, β-, and γ-HBCD) produced by the trans addition of bromine to cis,trans,trans-cyclododeca-1,5,9-triene (CDT). However, another seven diastereomers are theoretically possible and may be produced by trans addition of bromine across the double bonds of the other three isomers of 1,5,9-CDT. There are indications that small amounts of the minor HBCD isomers may be present in commercial HBCD mixtures or in products containing this brominated flame retardant (BFR). Such minor components may indeed derive from traces of other 1,5,9-CDTs in the cis, trans, trans starting material, however their formation may also be possible through isomerizations during the processing of this BFR or by bioisomerization subsequent to its release into the environment. Two of the seven additional diastereomers (δ- and ε-HBCD) were synthesized previously from trans,trans,trans-CDT. We now report the preparation of the remaining five diastereomers, ζ-, η-, and θ-HBCD from cis,cis,trans-CDT and ι- and κ-HBCD from cis,cis,cis-CDT, and their characterization by 1H NMR spectroscopy and X-ray crystallography. The availability of these further diastereomers of HBCD should aid in determining if the minor isomers are present in commercial samples of this BFR, in products containing HBCDs, or in environmental samples. We have also carried out an X-ray crystal structure determination on ε-HBCD, so that crystal structures are now available for all 10 HBCD diastereomers. KW - Brominated flame retardants KW - HBCDs KW - Minor isomers KW - X-ray PY - 2011 DO - https://doi.org/10.1016/j.chemosphere.2011.06.014 SN - 0045-6535 SN - 0366-7111 VL - 84 IS - 7 SP - 900 EP - 907 PB - Elsevier Science CY - Kidlington, Oxford AN - OPUS4-24298 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dorgerloh, Ute A1 - Theißen, H. A1 - Becker, Roland A1 - Nehls, Irene T1 - Probenahme von LHKW in Grundwasser: Vergleich von aktiver und passiver Probenahme KW - Grundwasser KW - Probenahme KW - LHKW KW - Pumpprobe KW - Diffusionsprobe KW - PDB PY - 2009 SN - 1618-3258 SN - 1617-5301 VL - 15 IS - 4 SP - 85 EP - 87 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-20624 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dorgerloh, Ute A1 - Theissen, H. A1 - Becker, Roland A1 - Hilbert, S. A1 - Nehls, Irene T1 - Probennahme und Quantifizierung von LHKW, Ethen und Methan in Grundwasser N2 - Der Einsatz aktiver (Pumpprobennahme, Schöpfprobennahme) und passiver (Diffusionsprobennahme) Probennahmetechniken zur Gehaltsbestimmung von LHKW sowie Ethen und Methan in Grundwasser wird aus ordnungsbehördlicher Sicht hinsichtlich der Vergleichbarkeit von Analysendaten untersucht. Am Beispiel einer Kontamination mit Trichlorethen sowie 1,2-Dichlorethen und Vinylchlorid kann deutlich gemacht werden, dass die Einsatzmöglichkeit der passiven Probennahme durch unzureichende Strömungsverhältnisse im Aquifer sowie biologische Aktivität im Pegelrohr begrenzt ist. Der aktiven Probennahme ist bei ungeklärten oder unzureichenden Strömungsverhältnissen im Grundwasserleiter daher der Vorzug zu geben. Das gaschromatographische Verfahren für Vinylchlorid mittels Dampfraumtechnik wird um die Quantifizierung von Methan und Ethen erweitert. Dabei werden für die Bewertung von Altlasten relevante Bestimmungsgrenzen von 0,1 µg/l (Vinylchlorid, Ethen) sowie 5 µg/l (Methan) erreicht. Aus der Validierung der Analysenmethode und den Ergebnissen verschiedener Probennahmen werden Toleranzbereiche für die Ergebnisse eines Grundwassermonitorings abgeschätzt. Diese Streubreiten von Monitoring- Ergebnissen sollten von Ingenieurbüros und zuständigen Ordnungsbehörden bei der Bewertung der komplexen Abbauprozesse eines LHKW-Grundwasserschadens beachtet werden. KW - Passive sampling KW - Active sampling KW - Groundwater KW - Trichloroethene KW - Vinyl chloride KW - Methane PY - 2010 DO - https://doi.org/10.1007/s00767-010-0144-7 SN - 1430-483X VL - 15 IS - 4 SP - 231 EP - 239 PB - Springer CY - Berlin ; Heidelberg AN - OPUS4-22617 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Roland A1 - Dorgerloh, Ute A1 - Sauer, Andreas A1 - Hofmann, Andrea T1 - Quality control in extended measurement campaigns: selection of contract laboratories by proficiency testing exemplified for the trace analysis of anilines in groundwater N2 - An interlaboratory comparison for the determination of aniline, nine methylated anilines and chlorinated anilines in contaminated groundwater (each compound between 1 µg L-1 and 750 µg L-1) was conducted as proficiency test for the selection of contract laboratories for a groundwater monitoring campaign. For the 13 participants, two different test sample series were prepared from a stabilized real case groundwater. Series A was the groundwater as sampled in the field and series B was prepared from series A by spiking with selected anilines. Homogeneity and stability investigations revealed that contaminated groundwater provides a viable basis for the preparation of ring test samples for the determination of anilines. Analytical procedures were limited to the standardized liquid–liquid extraction or solid-phase extraction in combination with gas chromatography/mass spectrometry (DIN 38407-16:1999). The robust consensus values were evaluated according to the standardized protocol of DIN 38402-45:2013. Robust reproducibility standard deviations ranged largely between 20?% and 60?% depending on the analyte. The proficiency assessment of individual participants combined the qualitative aspect of correct peak identification with the quantitative determination of individual concentrations within set limits in a unified approach. It could be shown that the accreditation status of laboratory and the existence of a standardized analytical procedure do not substitute a problem-related proficiency assessment of potential contractors. KW - Aniline KW - Chloroanilines KW - Methylanilines KW - Groundwater KW - Interlaboratory comparison KW - Proficiency test PY - 2014 DO - https://doi.org/10.1007/s00769-014-1072-5 SN - 0949-1775 SN - 1432-0517 N1 - Geburtsname von Sauer, Andreas: Buchholz, A. - Birth name of Sauer, Andreas: Buchholz, A. VL - 19 IS - 5 SP - 371 EP - 376 PB - Springer CY - Berlin AN - OPUS4-31756 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mönch, Bettina A1 - Becker, Roland A1 - Nehls, Irene T1 - Quantification of ethyl glucuronide in hair: effect of milling on extraction efficiency N2 - Aim: The objective of the study was to provide conclusive evidence for the effect of particle size reduction as by milling on the extractable content of ethyl glucuronide (EtG) of hair samples. Methods: A number of real case hair samples and two pooled hair materials with EtG contents in the range of 10–30 pg/mg were systematically compared with regard to the extraction yield of EtG after cutting to 2–3 mm length and pulverization with a ball mill. After the respective treatment the samples were submitted to aqueous extraction followed by quantification of EtG using HPLC-MS/MS. Results: It was unequivocally demonstrated that milling of hair samples prior to aqueous extraction significantly increases the extractable EtG content compared with cut hair. The effect ranged between 137 and 230% and was seen to occur regardless of the extent of pulverization. Cooling of samples was not necessary to prevent partial degradation of EtG during the grinding procedure. Conclusion: The options currently employed at choice in analytical practice (cutting or milling) were seen to significantly affect the extractable amount of EtG in hair. This is suspected to influence the degree of equivalence of quantification results obtained in different laboratories as well as their respective classification of a test subject's drinking behaviour on the basis of currently recommended cut-off values. PY - 2013 DO - https://doi.org/10.1093/alcalc/agt059 SN - 0735-0414 SN - 0309-1635 SN - 1464-3502 VL - 48 IS - 5 SP - 558 EP - 563 PB - Univ. Press CY - Oxford AN - OPUS4-28843 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Roland A1 - Altmann, Korinna A1 - Sommerfeld, Thomas A1 - Braun, Ulrike T1 - Quantification of microplastics in a freshwater suspended organic matter using different thermoanalytical methods – outcome of an interlaboratory comparison N2 - A sedimented freshwater suspended organic matter fortified with particles of polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) was employed in an interlaboratory comparison of thermoanalytical methods for microplastics identification and quantification. Three laboratories performed pyrolysis gas chromatography-mass spectrometry (Py-GC-MS), three others provided results using thermal extraction desorption followed by gas chromatography coupled to mass spectrometry (TED-GC-MS). One participant performed thermogravimetry-infrared spectroscopy (TGA-FTIR) and two participants used thermogravimetry coupled to mass spectrometry (TGA-MS). Further participants used differential scanning microscopy (DSC), a procedure based on micro combustion calorimetry (MCC) and a procedure based on elemental analysis. Each participant employed a different combination of sample treatment, calibration and instrumental Settings for polymer identification and quantification. Though there is obviously room for improvements regarding the between-laboratory reproducibility and the harmonization of procedures it was seen that the participants Performing Py-GC-MS, TED-GC-MS, and TGA-FTIR were able to correctly identify all polymers and to report reasonable quantification results in the investigated concentration range (PE: 20.0 μg/mg, PP: 5.70 μg/mg; PS: 2.20 μg/mg, PET: 18.0 μg/mg). Although for the other methods limitations exists regarding the detection of specific polymers, they showed potential as alternative approaches for polymer quantification in solid environmental matrices. KW - Interlaboratory comparison KW - Microplastics KW - Suspended organic matter KW - Pyrolysis PY - 2020 DO - https://doi.org/10.1016/j.jaap.2020.104829 VL - 148 SP - 1 EP - 6 PB - Elsevier B.V. AN - OPUS4-50977 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -