Some beverage and meat products are examined for the presence of N-nitrosodimethylamine by both Low- and High- Resolution Chemical Ionization Mass Spectrometry, compared with that by Electron Impact method to assess their reliability. All the data obtained from these MS methods have been treated by Statistical analysis, and the result obtained shows that the variances are not significant between each other, but the Low- Resolution Electron Impact MS with single ion monitoring gives rise to inconsistency among them.