The use of a new twin-electrode thin-layer cell to the study of homogeneous processes coupled to electrode reactions

A twin-electrode thin-layer cell (TETLC) was fabricated by a simple and low-cost procedure based on the use of gold CD-Rs and toner masks, providing channels with heights in the range of tens of μm. In this TETLC the solution species is generated at one electrode and diffuses away to the other one. The TETLC was characterized for operation as a generator–collector device with collection efficiency values of 100%. The fast analyte regeneration ensures the attainment of steady-state conditions at very short times for a reversible electrochemical system such as the ferri/ferrocyanide couple. Owing to the fast transport within the thin-layer solution, electrochemical processes involving EC mechanisms can be investigated as demonstrated by using ascorbic acid as an irreversible model system. Digital simulation was used to relate current at both electrodes (generator and collector) to the gap, flow rate and rate constant for a typical EC mechanism. Appropriate working curves were constructed in the range 0–103 s−1 at the experimental conditions employed in this study.