DESIGN AND ELECTROCHEMICAL EVALUATION OF AN OPTICALLY TRANSPARENT THIN-LAYER ELECTRODE FLOW CELL

A new thin-layer spectroelectrochemical cell with an optically transparent thin-layer electrode (OTTLE) has been designed and characterized using ferro/ferricyanide in aqueous solution with potassium chloride supporting electrolyte as a model system. The optical configuration is directed perpendicularly through the OTTLE and solution. The cell is equipped with two semi-transparent tin dioxide coated glass windows at a distance of 50-150 mum; that is, smaller than the semi-infinite electrochemical diffusion layer thickness, and can be used either in a stationary mode or in a continuous-flow system. Design is such that platinum wire or tin dioxide can be used as working electrode, the reference being Ag/AgCl. The formal potential obtained for the ferro/ferricyanide system is in good agreement with that expected; the difference between the anodic and cathodic peak potentials in cyclic voltammograms is less than 10 mV which suggests a good cell design. It is intended to apply the cell to in situ spectrophotometric monitoring of UV/vis/near-IR absorbance changes due to electrode reactions of biologically electroactive compounds. The complementary information from the two techniques should be valuable in elucidation of reaction rates and mechanism.