Changes in the resonance frequency of microcantilevers due to adsorpti
on of analyte vapor on exposed surfaces is shown to provide a novel me
ans for detection of the analyte. Frequency changes can be due to mass
loading or adsorption-induced changes in cantilever spring constant.
Sensitization to water vapor is demonstrated by coating cantilever sur
faces with hygroscopic materials, such as phosphoric acid, Cantilevers
coated with a thin gelatin film exhibit high sensitivity and a linear
response with changes in relative humidity, apparently due to changes
in the spring constant of the coated cantilever. In addition to frequ
ency response, static cantilever detection also changes with vapor ads
orption. Both phenomena can be used to detect adsorbed vapors with pic
ogram mass resolution.