Determination of alpha-solanine, alpha-chaconine and solanidine in plasma and urine by ultra-performance liquid chromatography-triple quadrupole mass spectrometry

An ultra-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS) method was developed for the determination of alpha-solanine, alpha-chaconine and solanidine in plasma and urine. The sample was acidified with aqueous solution containing 2% ( v/v if not specified) formic acid, and then cleaned-up by solid-phase extraction with a mixedmode cation exchange ( MCX) cartridge. The analysis of the glycoalkaloids was carried out on an Acquity UPLC BEH C-18 column (50 mmx2. 1 mm, 1. 7 mu m) with gradient elution of acetonitrile ( containing 0. 1% formic acid) and H2O ( containing 0.05% formic acid and 5.0 mmo/L ammonium acetate ). The analytes were detected by positive electrospray ionization tandem mass spectrometry in MRM mode, and quantified by external matrix-matched standard calibration. The cycle time of each analysis was 5.5 min. The calibration curves were linear in the range of 0. 3-100 ng/mL of the glycoalkaloids in plasma and urine. The correlation coefficients were 0. 997-0. 999. The limits of detection (S/N = 3) and quantitation (S/N = 10) were 0. 1 ng/mL and 0. 3 ng/mL. The average recoveries were 82%-112% and 96%-114% for the glycoalkaloids spiked in plasma and urine, respectively, with relative standard deviations of 4. 0%-16% and 2. 7%-17% ( n = 6). The method is simple, accurate and sensitive to detect the glycoalkaloids in plasma and urine for both clinical and forensic purposes.