Liquid chromatography coupled to tandem mass spectrometry(LC-MS/MS)is a highly specific and sensitive techniqueformeasuring metabolites.In this work,a method using thederivatization reaction combined withisotope dilutionLC-MS/MSanalysis to accurately quantify exogenous and endogenousglucose in plasma was developed.The mass spectrometer was carried outin multiple reaction monitoring mode(MRM)with electrospray ion source(ESI).Validation results indicated this method was robust,highly sensitive and significant improvement the accuracy of glucose quantification.Thecalibration curveshowed good linearity with correlation coefficient ofR2=0.9967 and the relative standard deviation(RSD%)calculated from triplicate analyses for each sample wasalways <2.5%.