Quantitative analysis of 1-(2-pyrimidinyl)piperazine in plasma by capillary gas chromatography-mass spectrometry.

A sensitive method for detecting and quantifying 1-(2-pyrimidinyl)piperazine, an important metabolite of buspirone, in human plasma was developed and validated. The range of the method is 0.2-15 ng/ml. The analyte was removed from buffered, sodium chloride-saturated plasma with benzene, extracted into aqueous acid, washed with diethyl ether and reextracted into benzene. The processed extract was derivatized with pentafluorobenzoyl chloride. Instrumental analysis involved on-column injection into a fused-silica capillary gas chromatography column and detection by selected-ion monitoring mass spectrometry.