Study of the chemical derivatization of zearalenone and its metabolites for gas chromatography-mass spectrometry analysis of environmental samples

This study compares different silylation procedures of zearalenone and its metabolites: alpha-zearalenol, beta-zearalenol, zearalanone, alpha-zearalanol and beta-zearalanol for gas chromatography-mass spectrometry (GC-MS) analysis. Four silylating agents among the most frequently used to derivatize polar organic compounds were tested: N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA), N,N-diethyltrimethylsilylamine (TMSDEA) and a commercial mixture of NO-bis(trimethylsilyl)acetamide, trimethylchlorosilane and N-trimethylsilyimidazole. Previous studies showed that the addition of polar and/or basic solvents can significantly improve the yield of a reaction of derivatization. In this work, four solvents were tested: pyridine, dimethylformamide, acetonitrile and acetone. The influence of each solvent was studied as a function of the silylating agent/solvent ratio. The influences of the temperature and of the reaction time on the reaction yields were also evaluated. A GC-MS quantitation method associating methanol chemical ionization and selected ion storage with three ions was developed and successfully tested on a reconstituted sediment spiked in zearalenone and its metabolites. (C) 2008 Elsevier B.V. All rights reserved.