This project is in the general area of analytical and surface chemistry and in the subfield of electroanalytical chemistry. During the tenure of this three-year continuing grant, Professor Johnson and his students will apply pulsed electrochemical techniques to the detection of polar and ionic aliphatic organic compounds having biological significance. Of particular interest to these studies are amino acids and peptides that contain thiol, disulfide, or thioether moieties. Such compounds traditionally do not yield to conventional electrochemical analysis at noble metal electrodes because of their electrochemical irreversibility. However, these functional moieties produce transient anodic signals at gold and platinum electrodes as a result of electrocatalytic reactions that occur during the formation of surface oxides and are thus detectable by pulsed techniques. This research builds upon accomplishments of the Johnson group under NSF grant CHE-8914700. %%% Results from this research project will expand fundamental knowledge of electrocatalytic reaction mechanisms for anodic processes that result in water-derived oxygen transfer. Additionally, this research should give rise to significant advances in detection technology for liquid chromatography wherein conventional photometric and fluorometric detection of the compounds of interest at levels less than nanomolar requires a priori chemical derivitization.