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 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 U6 - 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 - Bremser, Wolfram A1 - Rasenko, Tatjana A1 - Koch, Matthias T1 - Development and certification of a reference material for Fusarium mycotoxins in wheat flour N2 - Deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEN) are toxic secondary metabolites produced by several species of Fusarium fungi. These mycotoxins are often found together in a large variety of cereal-based foods, which are regulated by maximum content levels of DON and ZEN. To date, suitable certified reference materials (CRM) intended for quality control purposes are lacking for these Fusarium mycotoxins. In order to overcome this lack, the first CRM for the determination of DON, NIV and ZEN in naturally contaminated wheat flour (ERM®-BC600) was developed in the framework of a European Reference Materials (ERM®) project. This article describes and discusses the whole process of ERM®-BC600 development, including material preparation, homogeneity and stability studies, and an interlaboratory comparison study for certification. A total of 21 selected expert laboratories from different European countries with documented expertise in the field of mycotoxin analysis took part in the certification study using various gas and liquid chromatographic methods. The certified values and their corresponding expanded uncertainties (k=2) were assigned in full compliance with the requirements of ISO Guide 35 and are as follows: 102±11 µgkg-1 for DON, 1000±130 µgkg-1 for NIV and 90±8 µgkg-1 for ZEN. KW - Deoxynivalenol KW - Nivalenol KW - Zearalenone KW - Food KW - ERM KW - Quality assurance PY - 2013 U6 - https://doi.org/10.1007/s00216-013-6857-6 SN - 1618-2642 SN - 1618-2650 VL - 405 IS - 14 SP - 4755 EP - 4763 PB - Springer CY - Berlin AN - OPUS4-28303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neuhof, Torsten A1 - Koch, Matthias A1 - Rasenko, Tatjana A1 - Nehls, Irene T1 - Occurrence of zearalenone in wheat kernels infected with Fusarium culmorum N2 - The aim of this study was to investigate the distribution of zearalenone in wheat kernels contaminated with this mycotoxin. Kernels from a sample of a wheat harvest affected by Fusarium culmorum were sorted into six groups according to their visual attributes. Milled portions of these groups were analysed by high-performance liquid chromatography with fluorescence and diode array detection. The clean-up was performed with an immunoaffinity column after methanol/water (4:1, v/v) extraction. The zearalenone content of the unsorted kernel fraction was 74 µg/kg. The group of healthy-looking kernels was contaminated with only 6 µg/kg of zearalenone. The groups of kernels that appeared shrunken and chalky white, damage routinely caused by Fusarium, were contaminated with 170 and 117 µg/kg, respectively. A remarkably high level of zearalenone contamination, 2,184 µg/kg, was observed for the group of reddish kernels. An association between the presence of the red pigment aurofusarin and high levels of zearalenone was found. Therefore, this pigment may be used as a marker of high zearalenone content. KW - Zearalenone KW - Aurofusarin KW - Immunoaffinity column KW - HPLC-FLD/DAD PY - 2008 U6 - https://doi.org/10.3920/WMJ2008.1055 SN - 1875-0710 SN - 1875-0796 VL - 1 IS - 4 SP - 429 EP - 435 PB - Wageningen Academic Publishers CY - Wageningen AN - OPUS4-18329 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Merkel, Stefan A1 - Dib, Baha A1 - Maul, Ronald A1 - Köppen, Robert A1 - Koch, Matthias A1 - Nehls, Irene T1 - Degradation and epimerization of ergot alkaloids after baking and in vitro digestion N2 - The degradation and epimerization of ergot alkaloids (EAs) in rye flour were investigated after baking cookies and subsequently subjecting them to an in vitro digestion model. Different steps of digestion were analyzed using salivary, gastric, and duodenal juices. The degradation and bidirectional conversion of the toxicologically relevant (R)-epimers and the biologically inactive (S)-epimers for seven pairs of EAs were determined by a HPLC method coupled with fluorescence detection. Baking cookies resulted in degradation of EAs (2–30 %) and a shift in the epimeric ratio toward the (S)-epimer for all EAs. The applied digestion model led to a selective toxification of ergotamine and ergosine, two ergotamine-type EAs. The initial percentage of the toxic (R)-epimer in relation to the total toxin content was considerably increased after digestion of cookies. Ergotamine and ergosine increased from 32 to 51 % and 35 to 55 %, respectively. In contrast, EAs of the ergotoxine type (ergocornine, α- and β-ergocryptine, and ergocristine) showed an epimeric shift toward their biologically inactive (S)-epimers. Further experiments indicated that the selective epimerization of ergotamine EAs occurs in the duodenal juice only. These results demonstrate that toxification of EAs in the intestinal tract should be taken into consideration. KW - HPLC-FLD KW - Claviceps purpurea KW - Rye KW - Ergotoxine KW - Ergotamine KW - Deoxynivalenol KW - Nivalenol KW - Zearalenone KW - Food KW - ERM KW - Quality assurance PY - 2012 U6 - https://doi.org/10.1007/s00216-012-6386-8 SN - 1618-2642 SN - 1618-2650 VL - 404 IS - 8 SP - 2489 EP - 2497 PB - Springer CY - Berlin AN - OPUS4-27119 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Drzymala, Sarah A1 - Riedel, Juliane A1 - Köppen, Robert A1 - Garbe, L.-A. A1 - Koch, Matthias T1 - Preparation of 13C-labelled cis-zearalenone and its application as internal standard in stable isotope dilution analysis N2 - Pure U-[13C18]-labelled cis-zearalenone (cis-ZEA) has been prepared and characterised as internal standard (ISTD) for a reliable quantification of cis-ZEA in contaminated food and feed products. The cis-isomer of the naturally trans-configurated Fusarium mycotoxin zearalenone is often neglected. However, isomerisation easily occurs by exposure of ZEA to (UV-)light. Thus, the applicability of the new cis-ZEA ISTD was demonstrated in a long-term isomerisation study comparing naturally trans-ZEA-contaminated edible oil with spiked edible oil. To estimate the benefits of the newly prepared cis-ZEA ISTD, various approaches to quantify cis-ZEA by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) were compared. As a result, a significant bias was revealed if no appropriate cis-ZEA standards are used. Furthermore, the new ISTD was applied to the analysis of 15 edible oils by stable isotope dilution analysis in combination with HPLC-electrospray ionisation-MS/MS. One of the maize germ oils showed the presence of cis-ZEA above LOD (>0.3 µg/kg), whereas two out of 15 maize germ oils were found to be contaminated with trans-ZEA (range 17.0-31.0 µg/kg). KW - ZEA KW - Zearalenone KW - Isomerisation KW - Occurrence KW - Edible oil KW - SIDA KW - HPLC-MS/MS KW - Quantification KW - LC-MS/MS PY - 2014 U6 - https://doi.org/10.3920/WMJ2013.1610 SN - 1875-0710 SN - 1875-0796 VL - 7 IS - 1 SP - 45 EP - 52 PB - Wageningen Academic Publishers CY - Wageningen AN - OPUS4-30126 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Drzymala, Sarah A1 - Binder, J. A1 - Brodehl, Antje A1 - Penkert, M. A1 - Rosowski, M. A1 - Garbe, L.-A. A1 - Koch, Matthias T1 - Estrogenicity of novel phase I and phase II metabolites of zearalenone and cis-zearalenone N2 - Zearalenone and its cis-isomer, cis-zearalenone, are nonsteroidal mycotoxins that elicit an estrogenic response upon binding to the estrogen receptor. This study compares the estrogenicity of eleven congeners including novel metabolites as 15-OH-zearalenone, zearalenone-14-sulfate, α-cis-zearalenol and β-cis-zearalenol using the E-Screen assay. Overall, a change in the configuration from trans to cis retains significant estrogenic activity. In contrast, alterations of the aromatic moiety including hydroxylation and sulfation showed a markedly decreased estrogenicity when compared to zearalenone. KW - Zearalenone KW - Mycotoxin KW - MCF-7 KW - E-screen assay KW - Estrogenicity KW - Isomerization PY - 2015 U6 - https://doi.org/10.1016/j.toxicon.2015.08.027 SN - 0041-0101 SN - 1879-3150 VL - 105 SP - 10 EP - 12 PB - Elsevier CY - Oxford [u.a.] AN - OPUS4-34167 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Borzekowski, Antje A1 - Drewitz, T. A1 - Keller, Julia A1 - Pfeifer, Dietmar A1 - Kunte, Hans-Jörg A1 - Koch, Matthias A1 - Rohn, S. A1 - Maul, R. T1 - Biosynthesis and characterization of zearalenone-14-sulfate, zearalenone-14-glucoside and zearalenone-16-glucoside using common fungal strains N2 - Zearalenone (ZEN) and its phase II sulfate and glucoside metabolites have been detected in food and feed commodities. After consumption, the conjugates can be hydrolyzed by the human intestinal microbiota leading to liberation of ZEN that implies an underestimation of the true ZEN exposure. To include ZEN conjugates in routine analysis, reliable standards are needed, which are currently not available. Thus, the aim of the present study was to develop a facilitated biosynthesis of ZEN-14-sulfate, ZEN-14-glucoside and ZEN-16-glucoside. A metabolite screening was conducted by adding ZEN to liquid fungi cultures of known ZEN conjugating Aspergillus and Rhizopus strains. Cultivation conditions and ZEN incubation time were varied. All media samples were analyzed for metabolite formation by HPLC-MS/MS. In addition, a consecutive biosynthesis was developed by using Fusarium graminearum for ZEN biosynthesis with subsequent conjugation of the toxin by utilizing Aspergillus and Rhizopus species. ZEN-14-sulfate (yield: 49%) is exclusively formed by Aspergillus oryzae. ZEN-14-glucoside (yield: 67%) and ZEN-16-glucoside (yield: 39%) are formed by Rhizopus oryzae and Rhizopus oligosporus, respectively. Purities of ≥73% ZEN-14-sulfate, ≥82% ZEN-14-glucoside and ≥50% ZEN-16-glucoside were obtained by 1H-NMR. In total, under optimized cultivation conditions, fungi can be easily utilized for a targeted and regioselective synthesis of ZEN conjugates. KW - Mycotoxin KW - Zearalenone KW - Conjugate KW - Biosynthesis KW - Fusarium KW - Aspergillus KW - Rhizopus PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-444246 SN - 2072-6651 VL - 10 IS - 3 SP - Article 104, 1 EP - 15 PB - MDPI CY - Basel AN - OPUS4-44424 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Keller, Julia A1 - Haase, H. A1 - Koch, Matthias T1 - Hydroxylation and dimerization of zearalenone: comparison of chemical, enzymatic and electrochemical oxidation methods N2 - Investigations of the metabolic pathway of mycotoxins by microsomal techniques are often laborious, causing an increasing demand for easy and rapid simulation methods. Thus, the non-microsomal oxidation technique of electrochemistry coupled online to mass spectrometry (EC/MS) was applied to simulate phase I biotransformation of the Fusarium mycotoxin zearalenone (ZEA). The obtained transformation products were identified by high resolution mass spectrometry (FT-ICR) and HPLC-MS/MS. Transformation products (TPs) from EC/MS were compared to those of other oxidative methods such as Fenton-like and Ce(IV) reactions and metabolites derived from in vitro assays (human and rat liver microsomes). Electrochemical oxidization of ZEA was achieved by applying a potential between 0 and 2,500 mV vs. Pd/H2 using a flow-through cell with a boron-doped diamond working electrode. Several mono-hydroxylated TPs were generated by EC/MS and Fenton-like reaction, which could also be found in microsomal in vitro assays. EC and Ce(IV) led to the formation of structurally different ZEA dimers and dimeric quinones probably connected over covalent biaryl C-C and C-O-C bonds. Although the dimerization of phenolic compounds is often observed in natural processes, ZEA dimers have not yet been reported. This is the first report on the formation of stable ZEA dimers and their related quinones. The tested non-microsomal methods, in particular EC/MS, could be useful in order to predict the biotransformation products of mycotoxins, even in cases where one to one simulation is not always feasible. KW - Electrochemistry KW - Zearalenone KW - Dimer PY - 2017 U6 - https://doi.org/10.3920/WMJ2017.2213 SN - 1875-0710 SN - 1875-0796 VL - 10 IS - 4 SP - 297 EP - 307 PB - Wageningen Academic Publishers AN - OPUS4-43393 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -