Thickness-shear-mode acoustic-wave sensor based on n-butylamine plasma-deposition film for detection of carboxylic acid vapours Original Research Article

A n-butylamine plasma-deposited thickness-shear-mode (TSM) acoustic-wave sensor was successfully prepared on the surface of quartz crystal using a plasma polymerization technique. The response characteristics and mechanism of the TSM sensor with plasma-deposited n-butylamine film to a series of organic vapours were investigated, showing that the TSM sensor can be used for sensing carboxylic acid vapour efficiently and possesses considerably long useful lifetime for at least six months compared with the sensor coated by common chemical polymer. The sensor possessed good reproducibility, high stability and rapid response time to formic acid while coating with 96.40 μg of plasma-deposited n-butylamine. Compared with the acid–base titration method, the sensor can be used for the determination of formic acid sample with a recovery of 96.6 to 104.2%.