Mercurous Sulfate Reference Electrode Based on Solid Silver Amalgam

Abstract

A reference saturated mercurous sulfate electrode based on the non-toxic solid silver amalgam (SMSE-AgSA) as a substitute of liquid mercury was described. Long-term as well as short-term tests confirmed the stability of the SMSE-AgSA potential for a period of several months (E_SMSE-AgSA = +395.8 ± 0.06 mV vs. SCE; SD = 0.54 mV; N = 64). The voltammograms of lead and cadmium recorded against SMSE-AgSA or SCE were similar even though shifted along the E-axis. None of the electrodes was polarized to a significant extent in the potential range from -2000 mV to +2000 mV and under usual voltammetric currents. On the basis of the obtained results, SMSE-AgSA could be considered an equivalent substitute to the well-known mercurous sulfate electrode.