Development and validation of an LC-MS method for quantitation of ergot alkaloids in lateral saphenous vein tissue

A liquid chromatography-mass spectrometry (LC-MS) method for simultaneous quantitation of seven ergot alkaloids (lysergic acid, ergonovine, ergovaline, ergocornine, ergotamine, ergocryptine, and ergocristine) in vascular tissue was developed and validated. Reverse-phase chromatography, coupled to an electrospray ionization source, was used to separate and ionize alkaloids. Singly protonated molecular ions for each alkaloid and methysergide (internal standard), were detected by single-ion monitoring (SIM). Calibration curves were obtained over a linear range of 0.1 to 40 pmol on column with correlation coefficients better than 0.994. Method recoveries were 68.4% to 111.0%. Intra-assay precision was 3.4% to 16.1%. Matrix effects were observed and overcome by introducing matrix components into calibrant solutions to create matrix-diluted standards. Limits of detection and quantitation were 0.05 pmol and 0.1 pmol, respectively. Method ruggedness tests resulted in recoveries of 86.1 to 122% with an interassay precision of 7.9% to 22.8%. These results indicate that this method is suitable for quantitation of alkaloids extracted from in vitro-exposed vascular tissue.