Use of preconcentration techniques applied to a MS-based Electronic Nose

Four Swiss Emmental cheeses from four different factories were analysed with an "electronic nose" based on a mass spectrometer detector, the SMart Nose™. Three sampling methods, i.e. non-preconcentrated static headspace, Purge-and-Trap and solid phase microextraction (SPME), were compared in order to discriminate the cheese ripening ages. The use of a preconcen- tration technique was found to be helpful for this application due to the possibility to extract volatile compounds with higher molecular masses. From the two systems tested, the SPME was considered from far the best method because of its better repeata- bility, its simplicity and its compatibility with an autosampler.