Comparative Analysis of Methods for Determining the Primary Measuring Transducer Parameters of a Contact Conductometer

This study discusses the problem of increasing the accuracy of contact conductometers. This study also describes the main sources of error in the primary measuring transducer of a contact conductometer, which include the solution resistance, polarization resistance, and capacitance of the double electric layer and the characterization of the electrochemical processes on the primary measuring transducer electrodes. Moreover, this study presents the methods for determining the specific parameters that affect the impedance of the primary measuring transducer. Method 1 is based on the analysis of the amplitude-frequency characteristics of the active component of the impedance of the conductive cell of a contact conductometer filled with a solution. Method 2 is based on the determination of the active component of the impedance of the solution at the resonance frequency, i.e., at zero reactive components of the impedance. In Method 3, the active component of the impedance of the solution is determined at three different frequencies. Results showed that Method 2 can only reliably determine the active resistance of the solution. The cell constants are determined by Methods 1 and 3 in the same frequency range. Meanwhile, Method 2 uses a frequency that is several times higher than the upper limit of the frequency range. Notably, the cell constants determined by Methods 2 and 3 practically coincide with each other and significantly differ from the cell constants determined by Method 1.