Optimization of an LC–MS/MS analytical method for strychnine in livestock and fishery products

Abstract Strychnine, an alkaloid recognized for its antagonist effects on glycine and acetylcholine receptors, is highly toxic and banned in several countries. It is also set to restricted in Republic of Korea from 2024, creating a need for a quantitative test method to detect strychnine in livestock and fishery products. Therefore, this study aims to develop an analytical method to support the safety management of strychnine. The proposed method extracts and purifies strychnine from livestock and fishery products using ethyl acetate with 2% ammonium hydroxide and primary–secondary amine, respectively. The method demonstrated high sensitivity, with a coefficient of determination exceeding 0.99 and a limit of quantification of 0.005 mg/kg. Average recoveries ranged from 84.7 to 112.9%, with a coefficient of variation below 13.1%. These results meet the Codex guidelines (CAC/GL 71–2009). The developed method was employed to monitor strychnine residue levels in livestock and fishery products, but no residues were detected. The developed method can aid in the quality management of domestically distributed livestock and fishery products.