CLASSIFICATION OF COLA BEVERAGES ON THE BASIS OF MASS-SPECTRA MEASURED BY MEMBRANE INLET MASS-SPECTROMETRY

Classification of different cola drinks by membrane inlet mass spectro metry (MIMS) combined with different statistical computing methods is demonstrated. The spectra of cola drinks were measured directly using a single quadrupole mass spectrometer with a hollow fiber membrane inl et in standard MIMS and trap-and-release MIMS modes, and the spectra o btained were analyzed by principal component analysis and the mean pai rwise difference method, and classified via the k-NN classifier. The m ultivariate calculations showed that cola drinks from different manufa cturers can easily be differentiated from one another although the spe ctra of all drinks are usually very alike with minor differences in th e abundances of major ion peaks in the range m/z 50-199. The classific ation of drinks is rapid as a spectrum of one sample can be obtained i n a few minutes. (C) 1998 John Wiley & Sons, Ltd.