This study established a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for the simultaneous determination of strychnine (STR) and its metabolite strychnine N-oxide (SNO) in plasma, and to apply it in forensic toxicology analysis.Methods Chromatographic separation was performed on a XSelect HSS C18 (2.1 150 mm, 3.5 m) with gradient elution using 10 mmol/L ammonium formate (pH adjusted to 4 with formic acid) and methanol as the mobile phase at a flow rate of 0.3 mL/min.The injection volume was 5 L.Mass spectrometric detection was conducted using an AJS electrospray ionization source in positive ion mode with multiple reaction monitoring (MRM).Plasma samples were precipitated with acetonitrile, concentrated by nitrogen evaporation, and reconstituted prior to analysis.The method was validated for linearity, limit of detection (LOD), accuracy, precision, extraction recovery, and matrix effect.Results Good linearities were observed in the concentration ranges of 0.25-300 ng/mL for STR and 0.05-100 ng/mL for SNO (r 0.9997).The LODs were 0.1 ng/mL for STR and 0.01 ng/mL for SNO (S/N = 3).The accuracies for low, medium, and high quality control samples in plasma ranged from 90.56% to 101.22%.The intra-day and inter-day precisions (RSD) were 2.42% and 6.55%, respectively.The extraction recoveries were between 88.11% and 94.13%, and the matrix effects ranged from 82.25% to 97.55%.Conclusion The established method is sensitive, accurate, and reproducible, enabling the simultaneous detection of STR and SNO.It is suitable for the forensic identification of strychnine poisoning cases and for studies on the in vivo metabolism of strychnine.
Guangfeng Zhan (2026) studied this question.