Analysis of ergovaline in milk using high-performance liquid chromatography with fluorimetric detection.
A high-performance liquid chromatographic method for the determination of the mycotoxin ergovaline in goat's milk is described here. Ergotamine was used as an internal standard. For a sample size of 5.0 ml, the cleanup method included precipitation of milk protein with acetone. Then, ergovaline was extracted twice with chloroform and purified by elution on an Ergosil column. HPLC separation of the extract was accomplished on a C18 column: an isocratic elution, using acetonitrile-ammonium carbonate, was performed, and the analyte was detected by fluorimetry. The method was found to be linear between 0.7 and 8 ng ml(-1), a mean recovery rate of 99.8% was obtained, and the described assay appeared both repeatable and reproducible. The limit of detection and the limit of quantitation of ergovaline in milk were 0.2 ng ml(-1) and 0.7 ng ml(-1), respectively. In order to apply the proposed method, four lactating goats were administered the toxin intravenously at a dose of 32 mg kg(-1) body weight. The concentrations of the drug in plasma and milk were then determined at standardized intervals. Ergovaline (unequivocally identified by LC-MS-MS) could not be detected in the milk beyond eight hours post-dosing. Therefore, in goats, milk does not appear to be a major excretion route for the unmetabolized toxin.