D. Kohl et al., Systematic studies on responses of metal-oxide sensor surfaces to straightchain alkanes, alcohols, aldehydes, ketones, acids and esters using the SOMMSA approach, SENS ACTU-B, 70(1-3), 2000, pp. 43-50
Metal oxide sensors are widely used in the so-called "electronic noses", an
d it is proposed that these equipment can be used to objectify food aromas.
Due to the fact that, up to now, systematic approaches to correlate the int
ensity of sensor responses with the structure of a given volatile have scar
cely been performed [K. Suzuki, T. Takada, Highly sensitive odour sensors u
sing various SnO2 thick films, Sans. Actuators, B 24-25 (1995) 773-776; B.
Lalauze et ai., High sensitivity materials for gas detection, Sens. Actuato
rs, B 8 (1992) 237-243; K. Fukui, Detection and measurement of odor by sint
ered tin oxide gas sensor, Sens. Actuators; B 5 (1991) 27-32; J.W. Gardner,
A. Pike et al., Integrated array sensor for detecting organic solvents, Se
ns. Actuators, B 13-14 (1993) 355-357.], it is as yet not possible to predi
ct the sensitivity and the specivity of metal oxide preparations vs. a give
n chemical structure.
Using the SOMMSA approach [T. Hofmann et al., High resolution gas chromatog
raphy/selective odorant measurement by multisensor array (HRGC/SOMSA): a us
eful approach to standardize multisensor arrays for the use in the detectio
n of key food odorants, Sens. Actuators, B 41 (1997) 81-87.], mixtures of a
lkanes, alcohols, aldehydes tall with chain length of 8-14 carbon atoms) an
d acids (chain length of 2-10 carbon atoms) were applied to different self-
prepared metal oxide mixtures and the signal intensities were monitored. In
addition, quantitative experiments were performed to determine the detecti
on threshold of sensors. E.g. (E,E)-2,4-non-adienal, one of the most import
ant odorants in fresh cucumbers, could be clearly detected at a level below
4.0 ng/ml (He) by a sensor containing a mixture of ZnO and SnO2. (C) 2000
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