Comparison of two quantitative GC-MS methods for analysis of tomato aroma based on purge-and-trap and on solid-phase

Two analytical procedures, one based on purge- and-trap and the other on solid phase microextraction, both followed by GC-MS measurement using an ion-trap mass spectrometer in the electron impact mode, have been developed for determination and quantitation of up to 39 aroma compounds in fresh tomatoes. The method based on purge-and-trap for isolation of the volatile compounds uses Tenax as adsorbent and a hexane-diethyl ether mixture as solvent for elution. The method was validated for linearity, precision (better than 20% for most compounds), and limit of detection, which was approximately 1 ng g �1 . This methodenabledidentificationofupto30compoundsinreal samples. Use of SPME was considered as an alternative, to simplify sample treatment while maintaining the informa- tion level for the samples (e.g. the number of compounds detected) and quality of quantitation. A procedure based on SPME using a Carboxen/polydimethylsiloxane fibre was developed and validated for determination of 29 aroma compounds; precision was better than 20% and limits of detection ranged from 4 to 30 ng g �1 .