TY - THES A1 - Siegel, David T1 - Chemical Solutions to Current Issues in the Instrumental Quantification of Food Mycotoxins N2 - Mycotoxins are toxic secondary metabolites of ubiquitously occurring moulds. Through the consumption of contaminated foods, they can cause acute or chronic intoxications in humans. Here, it is demonstrated how covalent hydrazine chemistry can be used to improve the performance of instrumental methods for the quantification of trace level food mycotoxins. In the case of the Alternaria mycotoxin tenuazonic acid, pre-column derivatisation with 2,4-dinitrophenylhydrazine resolved chromatographic issues due to the chemical properties of the analyte and allowed for its rapid, sensitive and selective quantification in cereals and beer by high performance liquid chromatography- ion-trap two stage mass spectrometry (HPLC-IT-MS2). Tenuazonic acid could be detected for the first time in beer and buckwheat flour. Although the encountered levels were too low to cause acute intoxications, the frequency of contamination indicated possible health risks due to chronic exposure. In a second scenario, dynamic covalent hydrazine chemistry (DCHC) was exploited for a novel extraction and cleanup method applicable to the Fusarium mycotoxin zearalenone occurring in edible oils. Zearalenone was extracted by hydrazone formation on a hydrazinefunctionalised polymer resin and subsequently released hydrolytically for quantification by HPLC-fluorescence detection (HPLC- FLD). The high selectivity of the approach allowed for the omission of MS detection and immunoaffinity cleanup. The DCHC method was superior to previously published methods in terms of handling efforts, cost, precision and selectivity and is well suited for the monitoring of the current European maximum level for zearalenone in refined maize oil. In the second part of the dissertation, possible degradation routes of Alternaria mycotoxins upon storage and bread baking are discussed. In the frame of a kinetic study, it was shown that tenuazonic acid is degraded by two parallel processes, deacetylation and epimerisation, when stored in aqueous solution (half-life at 25 °C ~ 74 days). The primary degradation product deacetyl tenuazonic acid was less stable than its parent compound and degraded rapidly in beverage matrices. In model baking experiments it was furthermore revealed that alternariol, alternariol monomethyl ether and altenuene are stable under typical baking conditions. A newly identified degradation route, which is based on a sequence of hydrolysis and decarboxylation, caused only minor substance losses (< 1 %). Still, the degradation products could be detected in commercial rusk and crispbread by HPLC-tandem mass spectrometry (HPLC-MS/MS). N2 - Mykotoxine sind sekundäre Stoffwechselprodukte ubiquitärer Schimmelpilze. Über den Konsum belasteter Nahrungsmittel können sie beim Menschen, je nach Art und Ausmaß der Exposition, akute bzw. chronische Vergiftungen hervorrufen. Ziel der Arbeiten war es, durch chemische Methoden zwei Probleme aus dem Bereich der quantitativen Mykotoxinanalytik zu lösen. Hierbei ging es erstens um die Inkompatibilität des Alternaria Mykotoxins Tenuazonsäure mit üblichen Hochleistungsflüssigkeitschromatographie (HPLC) Säulen und zweitens um die selektive analytische Extraktion des in der Europäischen Union regulierten Fusarium Mykotoxins Zearalenon aus Speiseölen. Für beide Problemstellungen wurden Lösungen erarbeitet, die auf dem Einsatz kovalenter Hydrazinchemie im Rahmen der Probenvorbereitung beruhen. Die Verfahren wurden validiert und auf Verbraucherprodukte angewendet. Die Bestimmung der Tenuazonsäure erfolgte dabei nach Derivatisierung mit 2,4-Dinitrophenylhydrazin mittels HPLC-Ion-trap Massenspektrometrie (HPLC-IT-MS2). Für Zearalenon wurde eine neuartige Festphasenextraktionsmethode basierend auf dynamischer kovalenter Hydrazinchemie (DCHC) entwickelt und in Verbindung mit HPLC-Fluoreszenzdetektion (HPLC-FLD) eingesetzt. Beide Ansätze zeichnen sich durch hohe Selektivität, einfaches Handling und einen geringen Lösungsmittelverbrauch aus; alle Reaktionen erfolgen bei Raumtemperatur. So konnte Tenuazonsäure erstmals in Getränken (Bier) und Buchweizenmehl nachgewiesen werden. Der zweite Teil der Arbeit beschäftigt sich mit möglichen Abbaureaktionen der Alternaria Mykotoxine bei der Lagerung und Zubereitung von Lebensmitteln. Im Rahmen einer kinetischen Studie wurde gezeigt, dass Tenuazonsäure in wässriger Lösung über zwei parallele Prozesse, hydrolytische Deacetylierung und Epimerisierung, abgebaut wird (Halbwertszeit bei 25 °C ~ 74 Tage). Während das vornehmlich gebildete Produkt, Deacetyl-Tenuazonsäure, in wässriger Lösung stabil war, wurde es in Getränkematrices innerhalb weniger Tage abgebaut. In Modell-Backversuchen wurde weiterhin die Stabilität der Dibenzo- -pyron Derivate Alternariol, Alternariol-monomethylether und Altenuen untersucht. Unter typischen Backbedingungen erwiesen sich die Verbindungen als stabil. Ein erstmals belegter Abbaumechanismus für Alternariol und Alternariol-monomethylether, der auf einer Sequenz aus Hydrolyse und Decarboxylierung beruht, führte nur zu geringen Substanzverlusten (< 1 %). Dennoch konnten die Abbauprodukte mittels HPLC-Tandem-Massenspektrometrie (HPLCMS/MS) in extrudierten Produkten (Knäckebrot und Zwieback) nachgewiesen werden. T3 - BAM Dissertationsreihe - 71 KW - Alternaria KW - Mass spectrometry KW - Liquid chromatography KW - Quantification KW - Zearalenone PY - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-876 SN - 978-3-9813853-8-0 SN - 1613-4249 VL - 71 SP - 1 EP - 126 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-87 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koch, Matthias A1 - Bremser, Wolfram A1 - Köppen, Robert A1 - Krüger, Rita A1 - Rasenko, Tatjana A1 - Siegel, David A1 - Nehls, Irene T1 - Certification of reference materials for ochratoxin A analysis in coffee and wine N2 - Mycotoxins are important non-anthropogenic food and feed contaminants, which can be present on almost every agricultural commodity. Effective consumer protection therefore essentially depends on food surveillance by reliable quantitative analysis enabled by appropriate quality control. Certified (matrix) reference materials (CRMs) are versatile tools to support Quality assurance. However, in the case of ochratoxin A (OTA), a hepato- and nephrotoxic mycotoxin, which is regulated in various foods, there is a lack of suitable CRMs. This lack has now been overcome by the development of two European Reference Materials (ERM®) for the Determination of OTA in roasted coffee (ERM®-BD475) and red wine (ERM®-BD476). This article discusses the material preparation process as well as the results of homogeneity and stability testing. Furthermore, the results of the inhouse certification studies carried out at BAM Federal Institute for Materials Research and Testing are presented and discussed. Interlaboratory comparison studies involving selected expert laboratories with documented Expertise in the field of mycotoxin analysis were conducted to confirm the certified values determined by BAM. The certified ochratoxin A values and their corresponding expanded uncertainties (k = 2) were assigned in full compliance with the requirements of ISO Guide 35 and are as follows: (6.0 ± 0.6) µg kg-1 for roasted coffee, ERM®-BD475, and (0.52 ± 0.11) µg L-1 for red wine, ERM®-BD476. KW - OTA KW - Coffee KW - Wine KW - Food safety and quality KW - European reference materials KW - CRM PY - 2011 U6 - https://doi.org/10.1007/s00769-011-0783-0 SN - 0949-1775 SN - 1432-0517 VL - 16 SP - 429 EP - 437 PB - Springer CY - Berlin AN - OPUS4-24235 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Siegel, David A1 - Koch, Matthias A1 - Nehls, Irene T1 - Quantification of the Alternaria mycotoxin tenuazonic acid by HPLC-IT-MS2 after derivatization with 2,4-dinitrophenylhydrazine T2 - International Symposium on Chromatography CY - Münster, Germany DA - 2008-09-21 PY - 2008 AN - OPUS4-17792 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Siegel, David A1 - Koch, Matthias A1 - Nehls, Irene T1 - Quantification of the Alternaria mycotoxin tenuazonic acid by HPLC-Ion Trap MS2 after derivatization with 2,4-dinitrophenylhydrazine T2 - The fifth World Mycotoxin Forum 2008 CY - Noordwijk, Netherlands DA - 2008-11-17 PY - 2008 AN - OPUS4-18465 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 KW - Tenuazonic acid 2,4-dinitrophenylhydrazone KW - X-ray single crystal diffraction KW - Crystal structure PY - 2009 U6 - 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 - Babuscio, T. T1 - Mycotoxin management in the European cereal trading sector N2 - On the world scale, the European Union has established the most comprehensive regulations for mycotoxins in food and feed. These regulations, which areinter alia expressed in the form of maximum levels, largely affect cereal traders. To ensure the safety of their products and compliance with EU legislation traders are required to quantify the mycotoxin levels in their lots. However, while the analytical approaches of research and enforcement are well known and frequently reviewed in the scientific and legal literature, little detailed information is available on the mycotoxin management concepts of trade. The present article is intended to close this gap. On the basis of the results of two surveys conducted amongst European cereal traders in the years 2007 and 2009, three key issues in commercial mycotoxin management are outlined and discussed in the context of the current scientific literature. These are: the issue of sampling, the availability and performance of suitable analytical methods as well as issues evolving from variations between regulatory and contractual maximum levels. KW - Mycotoxins KW - Cereals KW - Trading KW - Analysis KW - Food safety PY - 2011 U6 - https://doi.org/10.1016/j.foodcont.2011.02.022 SN - 0956-7135 VL - 22 IS - 8 SP - 1145 EP - 1153 PB - Elsevier CY - Amsterdam AN - OPUS4-23526 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 KW - Deacetyl tenuazonic acid KW - Toluenesulfonylhydrazine KW - Hydrazone KW - Crystal structure PY - 2009 U6 - 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 - CONF A1 - Siegel, David A1 - Koch, Matthias A1 - Nehls, Irene T1 - Novel applications of hydrazine chemistry in the instrumental analysis of food mycotoxins T2 - Analytica 2010 conference CY - Munich, Germany DA - 2010-03-25 PY - 2010 AN - OPUS4-20973 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 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 - 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 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 U6 - 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 - CONF A1 - Siegel, David A1 - Maul, Ronald A1 - Köppen, Robert A1 - Koch, Matthias A1 - Nehls, Irene T1 - Current mycotoxin research at BAM T2 - Mycotoxin Workshop 2011 CY - Freising, Germany DA - 2011-05-30 PY - 2011 AN - OPUS4-23780 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Siegel, David A1 - Maul, Ronald A1 - Köppen, Robert A1 - Koch, Matthias A1 - Nehls, Irene T1 - Current mycotoxin research at BAM T2 - Gordon Reaearch Seminar & Conference on Mycotoxins and Phycotoxins CY - Waterville, ME, USA DA - 2011-06-11 PY - 2011 AN - OPUS4-23781 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, M.E.H. A1 - Steier, I. A1 - Köppen, Robert A1 - Proske, Matthias A1 - Korn, U. A1 - Koch, Matthias A1 - Siegel, David T1 - Cocultivation of phytopathogenic Fusarium and Alternaria strains affects fungal growth and mycotoxin production N2 - Aims: A laboratory study was conducted to evaluate the influence of cocultivation of toxigenic Fusarium (F.) and Alternaria (A.) fungi with respect to growth and mycotoxin production. Methods and Results: Fusarium culmorum Fc13, Fusarium graminearum Fg23 and two Alternaria tenuissima isolates (At18 and At220) were simultaneously or consecutively co-incubated on wheat kernels in an in vitro test system. Fungal biomass was quantified by determining ergosterol content. Three Fusarium toxins (DON, NIV and ZON) and three Alternaria toxins (AOH, AME and ALT) were analysed by a newly developed HPLC/MS/MS method. In simultaneous cocultures, the fungal biomass was enhanced up to 460% compared with individual cultures; Alternaria toxins were considerably depressed down to <5%. Combining At18 and At220 with Fg23 inhibited the toxin production of both fungal partners. In contrast, Fc13 increased its DON and ZON production in competitive interaction with both A. strains. Conclusions: The interfungal competitive effects aid the understanding of the processes of competition of both fungi in natural environments and the involvement of mycotoxins as antifungal factors. Significance and Impact of Study: Cocultivation significantly affects fungal growth and mycotoxin production of phytopathogenic Alternaria and Fusarium strains. The impact of mycotoxins on the interfungal competition is highlighted. KW - Alternaria KW - Cocultivation KW - Ergosterol KW - Fusarium KW - Interfungal competition KW - Multimycotoxin analysis PY - 2012 U6 - https://doi.org/10.1111/j.1365-2672.2012.05388.x SN - 1364-5072 VL - 113 IS - 4 SP - 874 EP - 887 PB - Wiley-Blackwell CY - Malden, Mass., USA AN - OPUS4-26932 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 KW - Deacetyl tenuazonic acid KW - X-ray single crystal diffraction KW - Crystal structure PY - 2009 U6 - 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 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 U6 - 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 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 U6 - 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 - CONF A1 - Siegel, David A1 - Rasenko, Tatjana A1 - Merkel, Stefan A1 - Koch, Matthias A1 - Nehls, Irene A1 - Panne, Ulrich T1 - Bestimmung von Alternaria-Mykotoxinen in Getreide und Bier T2 - ANAKON 2009 CY - Berlin, Germany DA - 2009-03-17 PY - 2009 AN - OPUS4-20113 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Siegel, David A1 - Koch, Matthias A1 - Bremser, Wolfram A1 - Köppen, Robert A1 - Krüger, Rita A1 - Nehls, Irene T1 - Mycotoxins and Acrylamide in Foods - A BAM perspective T2 - 12th Biological and Environmental Reference Material Symposium (BERM12) CY - Oxford, England DA - 2009-07-07 PY - 2009 AN - OPUS4-20114 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Siegel, David A1 - Merkel, Stefan A1 - Koch, Matthias A1 - Nehls, Irene T1 - Quantitative Analysis of Alternaria Mycotoxins in Foodstuffs T2 - Doktoranden-Seminar des Arbeitskreises "Separation Science" der Fachgruppe "Analytische Chemie" in der GDCh CY - Hohenroda, Germany DA - 2009-01-13 PY - 2009 AN - OPUS4-21075 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Siegel, David A1 - Koch, Matthias A1 - Nehls, Irene T1 - New results on the thermal degradation of Alternaria mycotoxins in food matrices T2 - 32. Mycotoxin Workshop CY - Copenhagen, Denmark DA - 2010-06-14 PY - 2010 AN - OPUS4-21090 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Siegel, David A1 - Koch, Matthias A1 - Nehls, Irene T1 - Novel applications of hydrazine chemistry in the instrumental analysis of food mycotoxins T2 - 32. Mycotoxin Workshop CY - Copenhagen, Denmark DA - 2010-06-14 PY - 2010 AN - OPUS4-21091 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Siegel, David A1 - Koch, Matthias A1 - Nehls, Irene T1 - Novel applications of hydrazine chemistry in the instrumental analysis of food mycotoxins T2 - Vrije Universiteit Amsterdam, Arbeitsgruppe Prof. Irth CY - Amsterdam, Netherlands DA - 2010-02-03 PY - 2010 AN - OPUS4-21092 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Siegel, David A1 - Koch, Matthias A1 - Nehls, Irene T1 - Quantitative Analysis of Alternaria Mycotoxins in Foodstuffs T2 - Universität Kassel, Arbeitsgruppe R. Faust CY - Kassel, Germany DA - 2009-02-06 PY - 2009 AN - OPUS4-21096 LA - deu 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 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 U6 - 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 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 U6 - 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 - TY - JOUR A1 - Siegel, David A1 - Koch, Matthias A1 - Nehls, Irene T1 - Wiederentdeckung eines alten Bekannten - 2,4-Dinitrophenylhydrazin in der Umweltanalytik 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 - CONF A1 - Siegel, David A1 - Rasenko, Tatjana A1 - Merkel, Stefan A1 - Koch, Matthias A1 - Nehls, Irene T1 - Determination of the Alternaria mycotoxin tenuazonic acid in cereals and beer and studies on its degradation in aqueous solution T2 - 31st Mycotoxin Workshop CY - Münster, Germany DA - 2009-06-15 PY - 2009 AN - OPUS4-20062 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Siegel, David A1 - Troyanov, S. A1 - Noack, J. A1 - Emmerling, Franziska A1 - Nehls, Irene T1 - Alternariol N2 - In the title compound (systematic name: 3,7,9-trihydroxy-1-methyl-6H-benzo[c]chromen-6-one), C14H10O5, the methyl group is shifted out of the molecular plane due to a steric collision, thus causing a slight twist of the benzene rings. The molecular structure is stabilized by an intramolecular O-H...O hydrogen bond, generating an S(6) ring. In the crystal, molecules are connected by intermolecular O-H...O hydrogen bonds into a three-dimensional network. KW - Alternariol KW - Kristallstruktur PY - 2010 U6 - https://doi.org/10.1107/S1600536810017502 SN - 1600-5368 VL - 66 IS - 6 SP - o1366 PB - Munksgaard CY - Copenhagen AN - OPUS4-21400 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Siegel, David A1 - Merkel, Stefan A1 - Koch, Matthias A1 - Nehls, Irene T1 - Quantification of the Alternaria mycotoxin tenuazonic acid in beer N2 - Tenuazonic acid (TA) is a major water soluble Alternaria mycotoxin. In the present work, a method for the quantification of TA in beer by liquid chromatography-ion-trap multistage mass spectrometry after derivatization with 2,4-dinitrophenylhydrazine is described. The method is based on a rapid workup procedure and features a LOD of 2 µg/kg without preconcentration using 400 mg of sample. Validation was performed for a working range of 8-500 µg/kg. A total of 43 beers of different brewing styles (pilsener, wheat beer, bock beer, dark beer and alcohol free beer) was analysed. TA was detected in 37 samples, 16 samples were above the LOQ. An average content of 11 µg/kg was found, the highest incidence being 175 ± 13 µg/kg. To our knowledge, this is the first report on the occurrence of TA in beer and beverages in general. KW - Tenuazonic acid KW - Mycotoxin KW - Beer KW - 2,4-Dinitrophenylhydrazine KW - Derivatization KW - Liquid chromatography/electrospray ionisation ion-trap multistage mass Spectrome PY - 2010 U6 - https://doi.org/10.1016/j.foodchem.2009.10.070 SN - 0308-8146 VL - 120 IS - 3 SP - 902 EP - 906 PB - Elsevier CY - Amsterdam [u.a.] ; Jena AN - OPUS4-21372 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Siegel, David A1 - Merkel, Stefan A1 - Bremser, Wolfram A1 - Koch, Matthias A1 - Nehls, Irene T1 - Degradation kinetics of the Alternaria mycotoxin tenuazonic acid in aqueous solutions N2 - The degradation kinetics of the Alternaria mycotoxin tenuazonic acid (l-TA) in aqueous buffer were studied over a period of 4 months at different pH levels (3.5 and 7.0) and temperatures (4, 25 and 40°C). l-TA and its degradation products were quantified by newly developed high-performance liquid chromatography methods with UV or electrospray multistage mass spectrometry detection. At pH 3.5, significant degradation occurred at 25 and 40°C, the respective l-TA half-lives being 73.8±0.4 and 14.0±0.1 days. Two degradation processes, epimerization and hydrolysis, were evaluated kinetically. The hydrolytically formed iso-deacetyl TA (iso-DTA, epimeric mixture) was found to be the stable end product of l-TA degradation under the conditions of this study. This indicates that iso-DTA as well as the l-TA epimer u-TA are formed in aqueous beverage matrices. KW - Tenuazonic acid KW - Alternaria KW - Epimerization KW - Degradation KW - Kinetics PY - 2010 U6 - https://doi.org/10.1007/s00216-009-3288-5 SN - 1618-2642 SN - 1618-2650 VL - 397 IS - 2 SP - 453 EP - 462 PB - Springer CY - Berlin AN - OPUS4-21373 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, M.E.H. A1 - Urban, K. A1 - Köppen, Robert A1 - Siegel, David A1 - Korn, U. A1 - Koch, Matthias T1 - Mycotoxins as antagonistic or supporting agents in the interaction between phytopathogenic Fusarium and Alternaria fungi N2 - The role of mycotoxins in the microbial competition in an ecosystem or on the same host plant is still unclear. Therefore, a laboratory study was conducted to evaluate the influence of mycotoxins on growth and mycotoxin production of Fusarium and Alternaria fungi. Fusarium culmorum Fc13, Fusarium graminearum Fg23 and two Alternaria tenuissima isolates (At18 and At220) were incubated on wheat kernels supplemented with alternariol (AOH), tetramic acid derivates (TeA), deoxynivalenol (DON) and zearalenone (ZEA) in an in vitro test system. Fungal biomass was quantified by determining ergosterol content. Three Fusarium toxins (DON, nivalenol and ZEA) and three Alternaria toxins (AOH, alternariol methyl ether (AME) and altenuene) were analysed by HPLC-MS/MS. If Alternaria strains grew in wheat kernels spiked with Fusarium mycotoxins, their growth rates were moderately increased, their AOH and AME production was enhanced and they were simultaneously capable of degrading the Fusarium mycotoxins DON and ZEA. In contrast, both Fusarium strains behaved quite differently. The growth rate of Fc13 was not distinctly influenced, while Fg23 increased its growth in wheat kernels spiked with AOH. TeA depressed the ergosterol content in Fc13 as well as in Fg23. The DON production of Fc13 was slightly depressed, whereas the ZEA production was significantly increased. In contrast, Fg23 restricted its ZEA production. Both Fusarium strains were not capable of degrading the Alternaria mycotoxin AOH. Mycotoxins might play an important role in the interfungal competitive processes. They influence growth rates and mycotoxin production of the antagonistic combatants. The observed effects between phytopathogenic Alternaria and Fusarium strains and their mycotoxins aid the understanding of the complexity of microbial competitive behaviour in natural environments. KW - Phytopathogen KW - Trichothecenes KW - Alternaria mycotoxins KW - Multi-mycotoxin analysis KW - Inter-fungal competition PY - 2015 U6 - https://doi.org/10.3920/WMJ2014.1747 SN - 1875-0710 SN - 1875-0796 VL - 8 IS - 3 SP - 311 EP - 321 PB - Wageningen Academic Publishers CY - Wageningen AN - OPUS4-32849 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -