Analysis of volatile flavour compounds by Proton Transfer Reaction-Mass Spectrometry: fragmentation patterns and discrimination between isobaric and isomeric compounds

The behaviour of 53 flavour compounds in Proton Transfer Reaction-Mass Spectrometry (PTR-MS) was investigated. Obtained spectra showed general rules on fragmentation patterns of alcohols, aldehydes, ketones and esters. Alcohols and aldehydes split off water while ketones hardly show any fragmentation. The mass fragments at m/z = 55 and 69 are potential markers for the presence of aldehydes and mono-unsaturated alcohols. Esters hydrolyse dependent on the ratio of the carbon chain length of their alcoholic part vs. their acidic part. Although fragmentation of individual compounds generally complicates the headspace spectra of complex mixtures, it can provide relevant information on discrimination of isobaric and isomeric compounds. (C) 2002 Elsevier Science B.V. All rights reserved.