Determining Conditional Constants of Conductometric Sensors

The calibration process for flow conductometric sensors of electrical conductivity and their concentration in solutions of NaOH, NaCl, and Na2CO3 are studied. Two-electrode sensors in glass tubes were used with platinum electrodes combined with the developed resistometer. The measuring system resistometer-sensor KSN-19, KSN-22, and KSN-23 operates on a pulsed alternating current at a frequency of 4 kHz. The calibration dependences of the concentration-resistance sensors in the above solutions were measured. Three main parameters of the sensors were determined by means of special software processing of the calibration data and their comparison with precise reference functions, namely, the "sensor constant" K-S, K-S1, and K-S3. It is shown that all characteristic parameters of the sensors depend on the chemical composition of the analyzed medium, and they are not constants. Theoretical substantiations of the observed regularity are given.