Automatic Magnetic Dispersive Solid-Phase Extraction Combined With LC-MS/MS for the Rapid Quantitation of Six Gelsemium elegans Alkaloids in Biological Samples

Abstract

In this study, an innovative, rapid, and automated method for quantifying six Gelsemium elegans alkaloids in biological samples using magnetic dispersive solid-phase extraction (MDSPE) and liquid chromatography tandem mass spectrometry (LC-MS/MS). Magnetic HLB extractant, NaH₂PO₄/Na₂HPO₄ buffer (0.2 M, pH 7) and acetonitrile were used in automatic MDSPE. The average pretreatment time was less than 2 min per sample. Atropine-d3 was employed as the internal standard (IS). The six alkaloids demonstrated a linear response (R² > 0.997) in the concentration range of 1∼100 ng/mL and 2∼200 ng/g. Precision and accuracy were within ± 15%, and the extraction recovery rates for each alkaloid ranged from 60.32% to 105.32%. The samples were found to be stable under various conditions. In summary, we present the first automated MDSPE-LC-MS/MS method for simultaneous quantification of six Gelsemium elegans alkaloids (gelsemine, koumine, humantenmine, humantenine, humantenidine, and humantenirine) in multiple biological matrices (whole blood, urine, liver). Unlike prior studies focused on one to two analytes or single matrices, this method achieves unparalleled specificity for six alkaloids with detection limits up to 0.01 ng/mL (0.02 ng/g), addressing critical gaps in forensic toxicology for complex poisoning cases.