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 - Weiz, S. A1 - Heinze, J. A1 - Marten, S. A1 - Prinz, Carsten A1 - Zimathies, Annett A1 - Garbe, L.-A. A1 - Koch, Matthias T1 - Automated solid-phase extraction coupled online with HPLC-FLD for the quantification of zearalenone in edible oil N2 - Established maximum levels for the mycotoxin zearalenone (ZEN) in edible oil require monitoring by reliable analytical methods. Therefore, an automated SPE-HPLC online system based on dynamic covalent hydrazine chemistry has been developed. The SPE step comprises a reversible hydrazone formation by ZEN and a hydrazine moiety covalently attached to a solid phase. Seven hydrazine materials with different properties regarding the resin backbone, pore size, particle size, specific surface area, and loading have been evaluated. As a result, a hydrazine-functionalized silica gel was chosen. The final automated online method was validated and applied to the analysis of three maize germ oil samples including a provisionally certified reference material. Important performance criteria for the recovery (70–120 %) and precision (RSDr <25 %) as set by the Commission Regulation EC 401/2006 were fulfilled: The mean recovery was 78 % and RSDr did not exceed 8 %. The results of the SPE-HPLC online method were further compared to results obtained by liquid&–liquid extraction with stable isotope dilution analysis LC-MS/MS and found to be in good agreement. The developed SPE-HPLC online system with fluorescence detection allows a reliable, accurate, and sensitive quantification (limit of quantification, 30 µg/kg) of ZEN in edible oils while significantly reducing the workload. To our knowledge, this is the first report on an automated SPE-HPLC method based on a covalent SPE approach. KW - Dynamic covalent hydrazine chemistry (DCHC) KW - Maize germ oil KW - Food KW - Mycotoxin KW - ZEA KW - Isomerisation KW - Occurrence KW - Edible oil KW - SIDA KW - LC-MS/MS KW - Quantification PY - 2015 U6 - https://doi.org/10.1007/s00216-015-8541-5 SN - 1618-2642 SN - 1618-2650 VL - 407 IS - 12 SP - 3489 EP - 3497 PB - Springer CY - Berlin AN - OPUS4-33067 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -