Rapid analysis of pentazocine in human plasma by liquid chromatography/mass spectrometry with sonic spray ionization

A rapid determination method for pentazocine in human plasma without complicated pretreatments has been constructed by liquid chromatography/mass spectrometry (LC/MS) with sonic spray ionization (SSI) using an Oasis HLB cartridge column. The reliability on our method was investigated for human plasma samples spiked with pentazocine and dextromethorphan as internal standard. The regression equation for pentazocine showed good linearity in the ranges of 30–1,250 and 1,250–10,000 ng ml−1; the detection limit was 19.5 ng ml−1 in human plasma. The sensitivity, accuracy and precision were satisfactory to quantify the wide range of therapeutic to toxic levels. Our method established enabled the determination of a single sample of pentazocine in human plasma only within 4 min, and allowed analysis of more than 100 samples per day. The present method seems applicable for actual cases encountered in the forensic and clinical practices.