A novel oscillator circuit with automatic capacitance compensation (ACC) capability has been coupled with QCM sensors coated with quinoxaline and pyrazine bridged cavitands to detected aromatic and chlorinated compounds in water. With double-side immersed 10-MHz crystals coated with the quinoxaline cavitand, the detection of toluene in deionized water was possible down to concentrations of few parts per million. The ACC oscillator advantageously provides the simultaneous measurement of the sensor resonant frequency, damping, and value of the compensated parallel capacitance. This enabled to observe that the analyte sorption in the cavitand coating not only brings about a mass uptake, but also an increase of losses, and, apparently, a rise in the coating average permittivity.
In-liquid sensing of chemical compounds by QCM sensors coupled with high-accuracy ACC oscillator / Ferrari, M.; Ferrari, V.; Marioli, D.; Taroni, A.; Suman, Michele; Dalcanale, Enrico. - STAMPA. - 1:(2004), pp. 20-25. (Intervento presentato al convegno IMTC/04 tenutosi a Como nel 18-20 maggio 2004).
In-liquid sensing of chemical compounds by QCM sensors coupled with high-accuracy ACC oscillator
SUMAN, Michele;DALCANALE, Enrico
2004-01-01
Abstract
A novel oscillator circuit with automatic capacitance compensation (ACC) capability has been coupled with QCM sensors coated with quinoxaline and pyrazine bridged cavitands to detected aromatic and chlorinated compounds in water. With double-side immersed 10-MHz crystals coated with the quinoxaline cavitand, the detection of toluene in deionized water was possible down to concentrations of few parts per million. The ACC oscillator advantageously provides the simultaneous measurement of the sensor resonant frequency, damping, and value of the compensated parallel capacitance. This enabled to observe that the analyte sorption in the cavitand coating not only brings about a mass uptake, but also an increase of losses, and, apparently, a rise in the coating average permittivity.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
