LONG OPTICAL PATHLENGTH THIN-LAYER SPECTROELECTROCHEMISTRY - STUDY OF HOMOGENEOUS CHEMICAL-REACTIONS

The convenience and advantage of the long optical pathlength thin-layer cell (LOPTLC) for monitoring the follow-up chemical reactions of electrochemically generated species are demonstrated. The hydrolysis rate constants for various electrogenerated o-quinone and p-quinoneimines are determined at both Pt and glassy carbon electrodes. In the case of Pt, adsorption of the organics was prevented by pretreating the electrode with KI so that the surface is covered with a monolayer of iodine. With the glassy carbon electrode, the effect of surface functional groups on the hydrolysis mechanism is observed when the electrode is preoxidized at high anodic potentials. The ability to see the influence of the surface to the rates and mechanisms of the hydrolysis is due to the high surface area to solution volume ratio of the LOPTLC.