While e-noses present a number of advantages over traditional
analysis, the sensors also present a number of shortcomings which
have yet to be solved. These include issues such as sensor poison-
ing, sensor drift and sensitivity. Selectivity and sensor drift have
been the focus of investigation. Specific to the food industry is
profile masking (e.g. ethanol) which affects the response. Profile
masking for example can be found in wines and often requires a
pre-processing step as described in Section 3.2. Recent trends to
overcome sensor shortcomings include combining semiconductor
chemical sensors with other types of gas sensors. While this
complicates the sampling system (requiring more bulk and elec-
tronics), this hybrid technology is able to compensate for the short-
comings in current chemical sensor technology. In particular, a
new generation of electronic noses referred to as mass spectrome-
try-based electronic noses (MS-E-nose) are increasingly used in the
literature where a MS-E-nose consists of a mass spectrometer
instrument without prior chromatographic separation.