[Simultaneous determination of trihexyphenidyl, chlorpromazine and clozapine in blood by GC-MS].

To develop a method to measure trihexyphenidyl, chlorpromazine and clozapine in human blood with GC-MS. 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. The lowest detection limits of trihexyphenidyl, chlorpromazine and clozapine were 0.3, 0.3 and 0.7 ng/mL (S/N > or = 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%. 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.