Liquid Chromatographic Determination of α-Solasonine in Frozen Green Peas as an Indicator of the Presence of Nightshade Berries

Abstract

Nightshade berries containing glycoalkaloids can be a contaminant in green peas. Methodology was developed to detect this contamination. The glycoalkaloid α-solasonine was extracted from frozen green peas with 1 % (v/v) acetic acid, cleaned up on a C18 cartridge, and determined by liquid chromatography with UV detection at 200 nm. Method performance characteristics for the determination of α-solasonine include linearity from 140 to 1500 ng injected (r= 0.9996-0.9999); recovery ranging from 68 to 79%; limit of quantitation (LOQ) = 4.5 ppm (280 ng standard), and limit of detection = 0.64 ppm (40 ng standard). At the LOQ, the expanded uncertainty at 95% confidence was 0.38 × the reported value. The method was applied to the detection of α-solasonine in frozen green peas in a 2-year study of 60 samples of frozen green peas from Ontario, Canada. None of the samples contained α-solasonine. No unripe berries of Solanum nigrum were detected visually in the samples.