Fused-Silica Capillary Dropping Mercury Electrode for Electrocapillary Measurements

A homemade fused-silica capillary dropping mercury electrode was used for the investigation of the adsorption behavior of a complex system by electrocapillary measurements. A mixture of soybean phospholipids, known as asolectin, was used for this purpose. The proposed setup with a fused-silica capillary electrode enables to observe aggregation and adsorption of asolectin aggregates at the mercury electrode surface and to determine the concentrations corresponding to the formation of asolectin micelles (critical micelle concentration, CMC) and liposomes (critical liposome concentration, CLC). Values of CMC (196.2–39.0 mg L−1) and CLC (1360–350 mg L−1) were obtained from the dependence of drop time on the logarithm of asolectin concentration in phosphate buffer pH 7.0 within a concentration range from 1 to 50 mmol L−1.