Sensitivity of modified bulk acoustic waves for the detection of phenols in the vapour phase

The potential ability of a bulk acoustic wave device oscillating in a thickness shear mode (BAWTSM) chemically modified with various compounds (4-amino-antipyrine, poly(vinyl pyrrolidone), Carbowax-20M, Triton X-100) for selective binding and assay of phenol compounds in the vapour phase has been investigated. The sensor was tested in a continuous flow system. The highest sensitivity was achieved with 4-amino-antipyrine as coating. It was estimated that the maximal frequency response was about 100 Hz for 20 μg of coating and for a phenol concentration of 0.05 mg dm−3 in air. The frequency response of the sensor to various phenol derivatives was correlated with adsorption and absorption during a dissolution process onto the surface of the coating sensor.