Development of a quantitative in-situ UV-Vis scanning reflectance spectroelectrochemical probe for the investigation of microwell electrodes

A study of the performance of fibre optic reflectance probes for the investigation of spectroelectrochemistry at Pt and Ag disk electrodes and Pt and Ag microwell electrodes is detailed. Specific attention is paid to the relationship between spectral and electrochemical measurements. As a test system, electrochemical oxidation and reduction of the redox system [Ir(Cl)6]3- is reported for chronoamperometric and cyclic voltammetric experiments. Good quantitative agreement between a spectroelectrochemical theory and the experimental data obtained is observed, if the time period of the experiment is maintained below ~ 10 s. At longer times, limitations associated with natural convection and edge effects are illustrated.A dynamic imaging technique is developed with the aid of a white resin supported working electrode (WSWE). This is shown to enable the tracking of the diffusion field of the electrode highlighting the edge and natural convection effects associated with the diffusion field generated. The ability for this dynamic imaging technique to produce quantitatively analysable results is investigated.A single-fibre reflectance probe is assessed for its ability to investigate spectroelectrochemical changes occurring in microwell electrodes that are used for lab-on-chip devices