Ergovaline is an ergot alkaloid produced by the symbiotic endophyte Epichloë coenophiala, which can colonize varieties of the cool-season grass tall fescue (Festuca arundinacea). It is the principle toxicant responsible for the vasoconstrictive and reproductive sequelae seen in "fescue toxicosis" in livestock which consume forage exceeding the threshold of toxicity established for this compound. A new method for extraction of ergovaline from tall fescue seed and straw was optimized and validated, on the basis of the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method, with high-performance liquid chromatography-fluorescence detection. Fourteen extraction solvents were tested; 2.1 mM ammonium carbonate/acetonitrile (50/50, v/v) had the highest and most consistent recovery (91-101%). Linearity, limit of detection, limit of quantitation, accuracy,and intra- and interday precisions for tall fescue seed and straw were 100-3500 μg/kg, 37 and 30 μg/kg, 100 μg/kg, 98%, 3.0 and 1.6%, and 3.8 and 1.0%, respectively. When the currently used solid-phase extraction (SPE) and QuEChERS methods were applied to 17 tall fescue straw samples, there was good agreement (correlation coefficient 0.9978). The QuEChERS method achieved the goals of eliminating chlorinated solvents and developing a fast, efficient, reliable method for quantitating ergovaline in tall fescue forage that can be applied in a high-throughput food safety laboratory.
Keywords: HPLC-fluorescence; ergot alkaloids; ergovaline; tall fescue.