HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF OCHRATOXIN-AIN ARTIFICIALLY CONTAMINATED COCOA BEANS USING AUTOMATED SAMPLE CLEANUP

A HPLC method is described for the analysis of ochratoxin A at low-ppb levels in samples of artificially contaminated cocoa beans. The sampl es are extracted in a mixture of methanol-water containing ascorbic ac id, adjusted to pH and evaporated to dryness. Samples in this state ar e then placed onto a Benchmate sample preparation workstation where C- 18 solid-phase extraction operations are performed. The resulting mate rials are evaporated to dryness and analyzed by reversed-phase HPLC wi th fluorescence detection. The method was evaluated for accuracy and p recision with R.S.D.s for multiple injections of sample and standard c alculated to be 1.1% and 2.5% for sample and standard, respectively. R ecoveries of ochratoxin A added to cocoa beans ranged from 87-106% ove r the range of the assay. (C) 1998 Elsevier Science B.V. All rights re served.