Abstract: An analytical method for the simultaneous determination of 15 anti-obesity drugs (caffeine, sibutramine, phenformin, etc.) in blood sample was developed using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). After a simple protein precipitation step, the HPLC separation was performed on an UltimateXB-C18 column with methanol and 20 mmol/L ammonium acetate (containing 0.1%(v/v) of glacial acetic acid) as the mobile phases in a gradient elution mode. The MS/MS detection was achieved by electrospray ionization in both positive and negative modes by rapid switching with selective reaction monitoring (SRM). The results showed that the limits of quantification of all anti-obesity drugs were in the range of 0.001~0.05 mg/L. The calibration curves of all anti-obesity drugs showed good linearity and the correlation coefficients were more than 0.99. The recoveries of all anti-obesity drugs at 3 spiked levels were in the range of 77.3%~110.8% with the intra-day and inter-day precisions less than 12.3%. The mass spectrum characterizations of 15 anti-obesity drugs were studied. The method is sensitive and reproducible for the detection of the 15 anti-obesity drugs in blood, and can also be applied to the determination of the anti-obesity drugs in pharmaceuticals or foods.

Key words: anti-obesity drugs, blood, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS)