A sensitive liquid chromatography-electrospray ionization-tandem mass spectrometric (LC-MS/MS) method for the simultaneous determination of aspirin (ASA) and its metabolite salicylic acid (SA) in human plasma has been developed and validated.The plasma ASA and SA were extracted using a liquid-liquid extraction (LLE) and the sample extract was injected onto the LC-MS/MS system.The limits of quantitation(LLOQ) for ASA and SA are both 25 ng/mL.This method allowed the reproducible and accurate quantification with the concentration rang of 25-10 000 ng/mL.This method could be applied to the quantitation aspirin and salicylic acid in human plasma.
