ABSTRACT
OBJECTIVE: To develop a method of HPLC/MS/MS to determine phenacetin and paracetamol in rat liver microsomal incubation system. METHODS: Samples were separated on XTerra MS C18 column, different ratios of methanol- 0.1% formic acid were used as the gradient eluent, and the flow rate was 0.2mL?min-1. The electrospray ion-quadrupole mass spectrometry and multiple reaction monitor were adopted to detect the concentration of phenacetin and paracetamol. RESULTS: The calibration curves were linear in the ranges of 45～9 000ng?mL-1(r=0.999 8)and 15.2～1 520ng?mL-1(r=0.999 6) for phenacetin and paracetamol respectively; The lowest limits of assay were 9ng?mL-1 and 10ng?mL-1.The average recoveries at three concentrations of phenacetin were (96.2?2.3)%～(98.3?2.4)% and those of paracetamol were (99.6?2.1)%～(100.2?2.6)%; RSD of the intra-day and inter-day were less than 5%. CONCLUSION: The method is rapid, sensitive and suitable for determination of phenacetin and paracetamol in rat liver microsomal incubation system.