Ambient ionization mass spectrometry can usually meet the requirements for rapid and direct screening of analytes in urine, saliva, plasma, skin and hair.l-3 However, some practical problems still exist in the application of this popular technique.For instance, it is still difficult to apply these ion sources directly for determination of organic substances in complex background without sample preparation or high performance separation steps.We have developed a convenient method by coupling frontal elution paper chromatography and desorption corona beam ionization mass spectrometry (DCBI-MS) for rapid determination of chlorphenamine added in herbal medicines or dietary supplements.According to this method, the alcohol extract of the herbal products was spotted directly to an isosceles triangular filter paper sheet, and then the paper sheet was developed under strong elution condition with the sample zone migrating at the solvent front.The analyte was finally condensed at the V-shaped tip which could be then placed under the visible plasma beam of DCBI for ionization.