Three-Electrode 30–60 μL Mini-Cell for Ecologically Conscious Analytical Voltammetry with Common Macro- and Microelectrodes

A 30–60 μL three-electrode electrochemical mini-cell for analytical voltammetry is described. The main module is a platinum tube (Pt-T) of 4 mm diameter and 5 mm height, which, when vertically placed on an upright working electrode, serves both as a counter electrode and electrolyte container. A fritted mini Ag/AgCl reference electrode completes the electrochemical cell by contacting the electrolyte through the top of the Pt tube. The Pt-T mini-cell produced typical cyclic voltammograms for 30 μL hexacyanoferrate­(III) with all types of working electrode tested, i.e., Pt, Au, boron-doped diamond and glassy carbon disc macroelectrodes, a cylindrical pencil lead electrode, and Pt disc microelectrodes. The mini-cell was also shown to be suitable for drug, hormone, antioxidant, and redox-label voltammetry, for operation of a glucose biosensor, and for quantitative differential pulse voltammetric analysis of paracetamol in standard addition mode. The significant technical advantages of the mini-cell are its cheapness and simplicity of construction, indefinite reusability, wide analyte adaptability, and ability to incorporate practically all standard macro- and microelectrode designs. Consequently, the mini-cell is not only a valuable option for voltammetric work in general, but more importantly it facilitates, in a simple and inexpensive manner, electrochemical analysis of samples with a mass or volume constraint or when the chemicals involved are costly. The microliters-volume electrochemical cell described in this study helps waste reduction and reduces chemical usage and, compared with conventional milliliters-volume beaker-type cells, is thus a green and sustainable electroanalytical tool that supports eco-friendly practice in research, commercial, and teaching laboratories.