A Simple and Low-Cost Ultramicroelectrode Fabrication and Characterization Method for Undergraduate Students

A laboratory experiment is described in which students fabricate disk-shaped gold and platinum microelectrodes with diameters of 10-50 mu m by sealing sodalime glass with metal microwires. The electrodes are characterized by performing cyclic voltammetry in aqueous and acetonitrile solution. Commercial microelectrodes are expensive (cost depends on the diameter of electrode) and may deter introduction of voltammetric experiments into laboratory classes at the undergraduate level. The students also fabricate a simple operational amplifier (op amp)-based potentiostat along with a low-current measuring device. This low-cost fabrication helps the students understand the details of instrumentation of a potentiostat with special knowledge in analog electronics. This experiment can be included in the electrochemistry laboratory course for undergraduate students. This experiment can also be incorporated into various undergraduate laboratory courses such as analytical chemistry, general chemistry, biochemistry, physical chemistry, and instrumentational methods of analysis.