Combined measurements of acoustic and dielectric loading on cavitand-coated TSM quartz sensors with ACC oscillator for in-liquid chemical detection

The combined and simultaneous measurements of both acousto-mechanical and dielectric loadings on purposely-sensitized TSM (thickness-shear-mode) quartz crystal resonators are evaluated as a multiparametric sensing approach for in-liquid chemical detection. This is made possible at low cost and in real time by the use of an automatic-capacitance-compensation (ACC) oscillator, which accurately keeps locked to the sensor resonance and advantageously outputs three signals respectively corresponding to the sensor series resonant frequency, quality factor, and parallel capacitance. Results are presented on cavitand-coated 10-MHz crystals in response to different chemical compounds in water solutions.