Designing and Using 3D-Printed Components That Allow Students To Fabricate Low-Cost, Adaptable, Disposable, and Reliable Ag/AgCl Reference Electrodes

Abstract

A reference electrode is an essential component of all three-electrode electrochemical measurements. Common commercial reference electrodes, including the saturated calomel electrode and Ag/AgCl reference electrode, are expensive with the former containing toxic mercury. Cheaper alternatives have been proposed including Ag/AgCl references made from pipets and test tubes. However, electrodes prepared in this way are difficult to work with and are limited by the size and shape of glass casings that are available. This paper proposes an in-house manufactured Ag/AgCl reference electrode that uses some 3D-printed components in the fabrication process. This electrode is cheap to manufacture ($5 vs $60–100 CAD for the commercial reference electrode), and the design can be quickly altered due to the 3D printer’s capabilities in rapidly printing new electrode shapes to suit different analysts’ needs. The lab-made reference electrodes demonstrated stability and consistency in peak potential measurements in the cyclic voltammetry (CV) experiments. In ferricyanide CV tests, the recorded differences in anodic and cathodic peak potential (ΔEp) values for the commercial reference electrode and both lab-made electrodes were 68 ± 9%, 70 ± 12%, and 69 ± 13%, respectively. For all tests, the results were statistically comparable with those of the commercial Ag/AgCl reference electrode.