Measurement of dissolved hydrogen concentration with clark electrode

Abstract

Clark electrode is a well-known sensor for measuring concentration of dissolved oxygen in a water solution. This type of electrochemical sensor has an advantage of enabling detection of very low oxygen concentration. Although Clark electrode is typically used for measurement of dissolved oxygen, our research showed that the same electrodes can be successfully applied for measurement of other dissolved gases. We investigated a possibility of applying the same principle to dissolved hydrogen concentration measurement, and also the possibility of simultaneous measurement of both dissolved oxygen and hydrogen concentrations in the same water solution. We adapted Clark electrode sensor to measure dissolved hydrogen by choosing the appropriate polarization voltage level. We studied the influences on dissolved hydrogen measurement, such as choice of polarization voltage, temperature, salinity, and solution pH. We investigated the polarization voltage influence on sensor sensitivity and observed hysteresis in sensitivity that occurs with cyclic increase and decrease of polarization voltage. We proposed and described measurement setup that was used for experimental verification of proposed measurement method and sensor characteristics. The measurement results of sensor characteristics are presented, regarding the influences of polarization voltage, temperature dependence, salinity (fresh water and 380/00 NaCl solution) and pH value (6, 7, 8).