Abstract: The sample were injected into HP-5 capillary column and analyzed with MSD detector. The proton pump deuterated compound was dissolved in acetonitrile. The purity was determined by the relative abundance ratio normalization calculation. The results of the Standard and perdeuterobenene tests were satisfying;the detection relative errors were not more than 2%. It can be used for the determination of the purity in deuterated compound rapidly and sensitively ,and especially used for monitoring a reaction process.