Abstract: Objective To develop a method to measure trihexyphenidyl, chlorpromazine and clozapine in human blood with GC-MS. Methods The specimens were alkalized（pH>10） and extracted with V（benzene）∶V（ethyl acetate）=1∶1, and qualitatively analyzed using GC-MS-Full Scan with internal standard SKF525A. The specimens were alkalized（pH>10） and extracted with V（benzene）∶V（ethyl acetate）=1∶1, and quantitatively analyzed using GC-MS-SIM with internal standard diazepam-d5. Results The lowest detection limits of trihexyphenidyl, chlorpromazine and clozapine were 0.3, 0.3 and 0.7 ng/mL（S/N≥3） respectively. The calibration curve in 20-10 000 ng/mL showed a good linear distribution. The recovery rate was 79.9% to 85.5%. The RSDs of intraday and interday were less than 5.1%. Conclusion The established method was simple, sensitive and accurate for simultaneous determination of trihexyphenidyl, chlorpromazine and clozapine in human blood, and can be applied in forensic toxicological cases.

Key words: forensic toxicology, GC-MS, trihexyphenidyl, chlorpromazine, clozapine, blood