TY - JOUR A1 - Siegel, David A1 - Merkel, Stefan A1 - Koch, Matthias A1 - Emmerling, Franziska A1 - Nehls, Irene T1 - 3-{1-[(2,4-Dinitrophenyl)hydrazino]ethylidene}-5-(1-methylpropyl)pyrrolidine-2,4-dione JF - Acta crystallographica E KW - Tenuazonic acid 2,4-dinitrophenylhydrazone KW - X-ray single crystal diffraction KW - Crystal structure PY - 2009 DO - https://doi.org/10.1107/S1600536809012458 SN - 1600-5368 VL - 65 IS - 5 SP - o988 EP - o989 PB - Munksgaard CY - Copenhagen AN - OPUS4-19736 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Siegel, David A1 - Blaske, Franziska A1 - Koch, Matthias A1 - Emmerling, Franziska A1 - Nehls, Irene T1 - Deacetyl tenuazonic acid p-toluenesulfonylhydrazone JF - Acta crystallographica E KW - Deacetyl tenuazonic acid KW - Toluenesulfonylhydrazine KW - Hydrazone KW - Crystal structure PY - 2009 DO - https://doi.org/10.1107/S1600536809048958 SN - 1600-5368 VL - E65 IS - 12 SP - o3136 Sup-1 - o3136 Sup-8 PB - Munksgaard CY - Copenhagen AN - OPUS4-20608 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Siegel, David A1 - Koch, Matthias A1 - Emmerling, Franziska A1 - Nehls, Irene T1 - Deacetyl tenuazonic acid JF - Acta crystallographica E KW - Deacetyl tenuazonic acid KW - X-ray single crystal diffraction KW - Crystal structure PY - 2009 DO - https://doi.org/10.1107/S1600536809015372 SN - 1600-5368 VL - 65 IS - 6 SP - o1201 PB - Munksgaard CY - Copenhagen AN - OPUS4-19429 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Siegel, David A1 - Rasenko, Tatjana A1 - Koch, Matthias A1 - Nehls, Irene T1 - Determination of the Alternaria mycotoxin tenuazonic acid in cereals by high-performance liquid chromatography-electrospray ionization ion-trap multistage mass spectrometry after derivatization with 2,4-dinitrophenylhydrazine JF - Journal of chromatography A N2 - Tenuazonic acid (TA) is a major Alternaria mycotoxin. In the present work a novel approach for the detection of TA in cereals by liquid chromatography–ion-trap multistage mass spectrometry after derivatization with 2,4-dinitrophenylhydrazine is described. The product of the derivatization reaction and its major MS2 fragments were characterised by Fourier transform-ion cyclotron resonance tandem mass spectrometry. Without preconcentration, the established method features a limit of detection of 10 µg/kg using 2 g of sample in a rapid workup procedure. Accuracy, precision and linearity were evaluated in the working range of 50–5000 µg/kg. TA was detected in 13 and quantified in 3 out of 27 cereal samples obtained from a local supermarket, the average content being 49 µg/kg (highest incidence: 851 ± 41 µg/kg). KW - Tenuazonic acid KW - 2,4-Dinitrophenylhydrazine KW - Derivatization KW - Liquid chromatography-electrospray ionization ion-trap multistage mass spectrome KW - Cereals PY - 2009 DO - https://doi.org/10.1016/j.chroma.2009.03.063 SN - 0021-9673 VL - 1216 IS - 21 SP - 4582 EP - 4588 PB - Elsevier CY - Amsterdam AN - OPUS4-19382 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koch, Matthias A1 - Bremser, Wolfram A1 - Köppen, Robert A1 - Siegel, David A1 - Töpfer, Antje A1 - Nehls, Irene T1 - Development of two certified reference materials for acrylamide determination in foods JF - Journal of agricultural and food chemistry N2 - Certified reference materials (CRMs) are a versatile tool for quality assurance in the chemical laboratory. In the case of acrylamide analysis, the availability of appropriate materials was rather limited. This lack of acrylamide matrix CRMs has now been overcome by the development of two European reference materials (ERM) for the determination of acrylamide in food (crispbread, ERM-BD272, and rusk, ERM-BD274). This article describes the preparation of the materials, provides the results of the homogeneity and stability studies, and presents and discusses the outcome of the certification studies. Expert laboratories from different European countries took part in the certification studies using various analytical methods. The acrylamide mass fractions were certified to 980 µg kg-1 for crispbread and 74 µg kg-1 for rusk. KW - Certified reference materials KW - ERM KW - Acrylamide KW - Crispbread KW - Rusk KW - Quality assurance KW - Homogeneity KW - Stability PY - 2009 DO - https://doi.org/10.1021/jf901329t SN - 0021-8561 SN - 1520-5118 VL - 57 IS - 18 SP - 8202 EP - 8207 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-19888 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Siegel, David A1 - Koch, Matthias A1 - Nehls, Irene T1 - Wiederentdeckung eines alten Bekannten - 2,4-Dinitrophenylhydrazin in der Umweltanalytik JF - GIT : Labor-Fachzeitschrift KW - Carbonyle KW - Derivatisierung KW - 2,4-Dinitrophenylhydrazin KW - Luft KW - Trinkwasser KW - PET PY - 2009 SN - 0016-3538 IS - Sonderausgabe: Umweltanalytik 2008 SP - 226 EP - 228 PB - GIT-Verlag CY - Darmstadt AN - OPUS4-18615 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Siegel, David A1 - Andrae, K. A1 - Proske, Matthias A1 - Kochan, Cindy A1 - Koch, Matthias A1 - Weber, M. A1 - Nehls, Irene T1 - Dynamic covalent hydrazine chemistry as a selective extraction and cleanup technique for the quantification of the Fusarium mycotoxin zearalenone in edible oils JF - Journal of chromatography A N2 - A novel, cost-efficient method for the analytical extraction of the Fusarium mycotoxin zearalenone (ZON) from edible oils by dynamic covalent hydrazine chemistry (DCHC) was developed and validated for its application with high performance liquid chromatography-fluorescence detection (HPLC-FLD). ZON is extracted from the edible oil by hydrazone formation on a polymer resin functionalised with hydrazine groups and subsequently released by hydrolysis. Specifity and precision of this approach are superior to liquid partitioning or gel permeation chromatography (GPC). DCHC also extracts zearalanone (ZAN) but not α-/β-zearalenol or -zearalanol. The hydrodynamic properties of ZON, which were estimated using molecular simulation data, indicate that the compound is unaffected by nanofiltration through the resin pores and thus selectively extracted. The method's levels of detection and quantification are 10 and 30 µg/kg, using 0.2 g of sample. Linearity is given in the range of 10-20,000 µg/kg, the average recovery being 89%. Bias and relative standard deviations do not exceed 7%. In a sample survey of 44 commercial edible oils based on various agricultural commodities (maize, olives, nuts, seeds, etc.) ZON was detected in four maize oil samples, the average content in the positive samples being 99 µg/kg. The HPLC-FLD results were confirmed by HPLC-tandem mass spectrometry and compared to those obtained by a liquid partitioning based sample preparation procedure. KW - Zearalenone KW - Extraction KW - Edible oil KW - Maize KW - Dynamic covalent hydrazine chemistry KW - Hydrazone KW - SPE KW - Hydrodynamic radius KW - HPLC-FLD PY - 2010 DO - https://doi.org/10.1016/j.chroma.2010.02.019 SN - 0021-9673 VL - 1217 IS - 15 SP - 2206 EP - 2215 PB - Elsevier CY - Amsterdam AN - OPUS4-21048 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Köppen, Robert A1 - Koch, Matthias A1 - Siegel, David A1 - Merkel, Stefan A1 - Maul, Ronald A1 - Nehls, Irene T1 - Determination of mycotoxins in foods: current state of analytical methods and limitations JF - Applied microbiology and biotechnology N2 - Mycotoxins are natural contaminants produced by a range of fungal species. Their common occurrence in food and feed poses a threat to the health of humans and animals. This threat is caused either by the direct contamination of agricultural commodities or by a "carry-over" of mycotoxins and their metabolites into animal tissues, milk, and eggs after feeding of contaminated hay or corn. As a consequence of their diverse chemical structures and varying physical properties, mycotoxins exhibit a wide range of biological effects. Individual mycotoxins can be genotoxic, mutagenic, carcinogenic, teratogenic, and oestrogenic. To protect consumer health and to reduce economic losses, surveillance and control of mycotoxins in food and feed has become a major objective for producers, regulatory authorities and researchers worldwide. However, the variety of chemical structures makes it impossible to use one single technique for mycotoxin analysis. Hence, a vast number of analytical methods has been developed and validated. The heterogeneity of food matrices combined with the demand for a fast, simultaneous and accurate determination of multiple mycotoxins creates enormous challenges for routine analysis. The most crucial issues will be discussed in this review. These are (1) the collection of representative samples, (2) the performance of classical and emerging analytical methods based on chromatographic or immunochemical techniques, (3) the validation of official methods for enforcement, and (4) the limitations and future prospects of the current methods. KW - Mycotoxins and fungal metabolites KW - Food KW - Rapid and validated methods KW - Regulations KW - Sampling KW - Multi-mycotoxin determination PY - 2010 DO - https://doi.org/10.1007/s00253-010-2535-1 SN - 0175-7598 VL - 86 IS - 6 SP - 1595 EP - 1612 PB - Springer CY - Berlin AN - OPUS4-21184 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Siegel, David A1 - Feist, M. A1 - Proske, Matthias A1 - Koch, Matthias A1 - Nehls, Irene T1 - Degradation of the alternaria mycotoxins alternariol, alternariol monomethyl ether, and altenuene upon bread baking JF - Journal of agricultural and food chemistry N2 - The stability of the Alternaria mycotoxins alternariol, alternariol monomethyl ether, and altenuene upon bread baking was investigated by model experiments using a spiked wholemeal wheat flour matrix. For alternariol and alternariol monomethyl ether, but not for altenuene, degradation products, formed through a sequence of hydrolysis and decarboxylation, could be identified in pilot studies. The simultaneous quantification of alternariol, alternariol monomethyl ether, altenuene, and the degradation products was achieved by a newly developed high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) multimethod. The obtained quantitative data indicate that the Alternaria mycotoxins are barely degraded during wet baking, while significant degradation occurs upon dry baking, with the stability decreasing in the order alternariol monomethyl ether > alternariol > altenuene. The novel degradation products could be detected after the wet baking of flour spiked with alternariol and in a sample survey of 24 commercial cereal based baking products. KW - Alternariol monomethyl ether KW - Alternariol KW - Altenuene KW - Degradation KW - Baking KW - Bread KW - HPLC-MS/MS PY - 2010 DO - https://doi.org/10.1021/jf102156w SN - 0021-8561 SN - 1520-5118 VL - 58 IS - 17 SP - 9622 EP - 9630 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-21909 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koch, Matthias A1 - Köppen, Robert A1 - Siegel, David A1 - Witt, Angelika A1 - Nehls, Irene T1 - Determination of total sulfite in wine by ion chromatography after in-sample oxidation JF - Journal of agricultural and food chemistry N2 - Sulfur dioxide (SO2) or sulfites are the most common preservatives used in winemaking. The level of total SO2 is subject to regulation. Currently, the regulatory determination of total SO2 (including sulfites) is done by the optimized Monier–Williams (OMW) method, which includes time-consuming distillation and titration steps. This paper describes the development and application of an alternative, rapid, straightforward, and reliable method for the determination of total sulfite in wine. In this method, a simple oxidation step using alkaline hydrogen peroxide (H2O2) solution is followed by ion chromatographic (IC) analysis of sulfate coupled with conductometric detection. Thirteen wines were analyzed in order to compare the in-sample oxidation method with the OMW-procedure. A t-test revealed satisfying compliance regarding sample preparation, i.e., alkaline H2O2 treatment and acidic distillation (OMW method). Comparable results were also obtained between IC analysis and acid/base titration. Our results indicate that the novel method (limit of quantification: 4 mg SO2 L-1) is well suited for the cost-efficient monitoring of regulatory limits. KW - Sulfur dioxide KW - Wine analysis KW - Hydrogen peroxide oxidation KW - IC KW - Optimized Monier-Williams method PY - 2010 DO - https://doi.org/10.1021/jf102086x SN - 0021-8561 SN - 1520-5118 VL - 58 IS - 17 SP - 9463 EP - 9467 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-21912 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -