Based on the advantages of ambient mass spectrometry in the fast and direct detection on samples without any pre treatment,an ambient mass spectrometric method was developed for the rapid and direct detection of drug tablets.In the experiment,a home made desorption electrospray ionization(DESI) device was fabricated for the fast mass spectrometry(MS) detection of commercial paracetamol tablets for the cold,achieving the molecule structural information of tablets without any pre treatment.In the quantitative analysis of tablets by DESI-MS,the tablets of standard paracetamol were made starch used as the main matrix to avoid the effect of matrix on ionizations.Under the optimized conditions,this method was applied in the quantitative detection of paracetamol in real tablets.Results showed that there was a good linear relationship for paracetamol in the range of 035-452 mg/mm2 with a correlation coefficient(r2) of 0998 2.The limit of quantitation and limit of detection were 1903 ng/mm2 and 0237 ng/mm2,respectively.The spiked recoveries for paracetamol were in the range of 102%-114%.The method was used for the direct detection of paracetamol in three commercial paracetamol tablets.Compared with the data provided by the pharmaceutical manufacturers,the relative standard deviations(RSD) of 72%-12% were obtained.The present work confirmed that,with the advantages of drugs rapid detection,DESI-MS provided an efficient and effective tool for quality control of drugs.