Ultra-performance liquid chromatography–tandem mass spectrometric method for the determination of strychnine and brucine in mice plasma

A selective, simple and efficient method-ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) was developed for determination of two toxic alkaloids, namely strychnine and brucine in mice plasma. The UPLC separation was carried out using a 1.7 μm BEH C18 column (50 mm × 2.1 mm) with a mobile phase consisting of methanol:0.1% formic acid (25:75, v/v), hence providing high efficiency, high resolution and excellent peak shape for the analytes and internal standard. The method was validated over the range of 2.48–496.4 ng/ml for strychnine and 2.64–528 ng/ml for brucine, respectively. Intra- and inter-day accuracy ranged from 95.0% to 107.9% for strychnine, 93.4% to 103.3% for brucine, and the precisions were within 13.8%. The extraction recoveries of both the two alkaloids exceed 81.9%. With a simple and minor sample preparation procedure and short run-time (<3 min), the proposed method was applicable for the pharmacokinetic and toxicological analysis of strychnine and brucine in vivo.