Forensic analysis using ultra-high-performance liquid chromatography–tandem mass spectrometry with solid-phase extraction of α-solanine and α-chaconine in whole blood

PURPOSE: The potato glycoalkaloids (PGAs), α-solanine and α-chaconine can exert adverse effects on human health when consumed in excess. This study aimed to investigate the optimal extraction method for the quantitative analysis of PGAs in whole blood by using ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) and to apply this validated method to postmortem blood. METHODS: A total of 200 µL of human whole blood was prepared for PGA extraction. For validation, a solid-phase extraction (SPE) using Oasis(®) PRiME HLB, in which extraction could be performed in three simple steps (sample loading, washing, and elution) was used, with no need for both conditioning and equilibration of columns for sample preparation. RESULTS: In this method, the limit of detection and the lower limit of quantification (LLOQ) of both α-solanine and α-chaconine were 1 and 2 µg/L, respectively. The calibration curves of the two compounds were obtained with good linearity in the range of 2–100 µg/L. The recovery rates at the LLOQ of α-solanine and α-chaconine were ≥ 91.8% and ≥ 85.9%, respectively. The validation data (intra- and inter-day combined) for accuracy ranged from 93.5 to 106.6% for α-solanine and from 93.9 to 107.7% for α-chaconine. This validated method was successfully applied to one forensic autopsy case, and the concentrations of α-solanine and α-chaconine in the postmortem cardiac blood were 45.1 and 35.5 µg/L, respectively. CONCLUSIONS: This validated UHPLC–MS/MS with SPE for quantitative analysis of PGAs could be useful in forensic toxicology. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s11419-018-0452-7) contains supplementary material, which is available to authorized users.