Abstract: Objective To develop a liquid chromatography-tandem mass spectrometry （LC-MS/MS） screening method for 45 poisonous alkaloids in blood. Methods Identification was based on the compound’s retention time and two precursor-to-production transitions. The method involved a liquid-liquid extraction （LLE） followed by LC-MS/MS with multiple-reaction monitoring （MRM）. When 1 mL of blood was extracted with diethyl ether at pH=9.2 with SKF525A as the internal standard, the target compounds were analyzed with LC-MS/MS in the positive ionization mode. Results The target alkaloids had good linearity （r>0.995 1）, both the intra-day precision and inter-day precision being less than 14.77%. The limits of detection ranged from 0.05 to 25 ng/mL in blood. Conclusion The method is selective and sensitive in detecting poisonous alkaloids with a total running time of 12 minutes; therefore it was successfully applied to some actual cases of suspected alkaloids poisoning.

Key words: forensic toxicology, chromatography, liquid, tandem mass spectrometry, alkaloids, blood