Critical impact of chloride containing reference electrodes on electrochemical measurements

Chloride containing reference electrodes, such as various silver-silver chloride electrodes, are well established in electrochemical analyses. Usually less attention is paid to the influence of potential chloride contamination of electrochemical measurements. Herein, the impact of the chloride leakage rate is studied by means of experiments concerning the anodic oxidation of aluminum. Based on the results, the authors determine critical leakage rates, depending on typical electrolyte volumes and experimental conditions. The results demonstrate that chloride leakage can significantly influence electrochemical measurements, even at ultra-low leakage rates. A guideline for the usage of chloride containing reference electrodes is deduced from the experimental results and theoretical considerations.