Use of preconcentration techniques applied to a MS-based "electronic nose"

Four Swiss Emmental cheeses from four different factories were analysed wit h an "electronic nose" based on a mass spectrometer detector, the SMart Nos e(TM). Three sampling methods, i.e. non-preconcentrated static headspace, P urge-and-Trap and solid phase microextraction (SPME), were compared in orde r to discriminate the cheese ripening ages. The use of a preconcentration t echnique was found to be helpful for this application due to the possibilit y 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 repeatability, its simplicity and its compatibility with an aut osampler.