Critical study of and improvements in chromatographic methods for the analysis of type B trichothecenes

Various analytical methods used in the analysis of type B trichothecenes (d eoxynivalenol, nivalenol, 3- and 15-acetyldeoxynivalenol) in cereals were c ompared and optimised in this work. These methods use either GC-electron-ca pture detection (ECD) of trimethylsilyl, trifluoroacetyl and heptafluorobut yryl derivatives or HPLC with W or photodiode array detection of analytes. A new HPLC procedure using fluorescence detection prior derivatisation with coumarin-3-carbonyl chloride has been also tested. Five extraction solvent s and two solid-phase extraction cartridges (silica, Florisil) plus a espec ial clean-up column (MycoSep 225) were compared in order to obtain the best recovery of the mycotoxins with minimal presence of coextractives in the c hromatograms. The chosen extraction solvent was a mixture of acetonitrile-w ater (84:16, v/v). The MycoSep 225 column was chosen as the best alternativ e for clean-up of grain samples. For GC-ECD analysis, derivatisation of ana lytes with heptafluorobutyric anhydride prior the final determination was c hosen as the most suitable procedure. HPLC-photodiode array (at 221 nm) ana lysis was more suitable for determination of type B trichothecenes than HPL C of the fluorescent coumarin-3-carbonyl derivatives. Recoveries obtained i n spiked corn, rice and wheat are reported. The utility of the proposed met hodology was assayed in cereal cultures of various Fusarium strains. (C) 20 01 Elsevier Science B.V. All rights reserved.