Abstract: Objective To establish a method for determination of strychnine and brucine in formaldehyde fixed tissue by LC-MS/MS analysis. Methods The samples were pretreated with solid phase extraction using SCX cartridges and separated on SB-C18 column with mobile phase 0.1% formic acid ∶ 0.1% formic acid-acetonitrile （75∶25）. Electrospray ionization （ESI） source was utilized and operated in positive ion mode. Multiple reactions monitoring （MRM） mode was applied. External standard method was applied for quantitation. Results The chromatographic separation of strychnine and brucine in formaldehyde fixed nephritic and hepatic tissues resulted successfully. The standard curve was linear in the range of 0.002～2.0 μg/g for strychnine and brucine in formaldehyde fixed tissues, and the correlation coefficient was more than 0.996. The limits of detection （LOD） of strychnine and brucine in nephritic tissues were 0.06 ng/g and 0.03 ng/g, respectively. The LOD of both chemicals were 0.3 ng/g in hepatic tissues. The extraction recovery rate was more than 74.5%. The precision of intra-day and inter-day were both less than 8.2%. Conclusion Strychnine and brucine can be sensitive to be determined in formaldehyde fixed tissue by LC-MS/MS analysis. It can be applied in the forensic toxicological analysis.

Key words: forensic toxicology, LC-MS/MS, strychnine, brucine, formaldehyde fixed