CALIBRATION METHOD FOR DETERMINATION OF ACIDS AND BASES WITH PIEZOELECTRIC QUARTZ-CRYSTAL SENSORS

Based on the linear relation between the frequency response of the pie zoelectric quartz crystal sensor and the conductivity of the solution to be measured, calibration models for quantitative analysis of acid a nd base systems are derived and are verified both theoretically and ex perimentally. Then quantitative determinations of aspirin and penicill ine were done with the calibration technique. The quantitative analysi s results of the two true pharmaceutical systems indicate that the mod els, combining linear regression, can give precise and accurate concen tration estimates, which can reduce the influence of the presence of i nterferences.