A recently developed microcantilever probe with integrated piezoresistive r
eadout has been applied as a gas sensor. Resistors, sensitive to stress cha
nges, are integrated on the flexible cantilevers. This makes it possible to
monitor the cantilever deflection electrically and with an integrated refe
rence cantilever background noise is subtracted directly in the measurement
. A polymer coated cantilever has been exposed to vapors of various alcohol
s and the resulting cantilever response has been interpreted using a simple
evaporation model. The model indicates that the cantilever response is a d
irect measure of the molecular concentration of alcohol vapor. On the basis
of the model the detection limit of this cantilever-based sensor is determ
ined to be below 10 ppm for alcohol vapor measurements. Furthermore, the ti
me response of the cantilever can be used to distinguish between different
alcohols due to a difference in the evaporation rates. (C) 2000 American In
stitute of Physics. [S0003-6951(00)02118-5].