The swface-enhanced Raman spectra (SERS) of dopamine, norepinephrlne, epinephrine, eplnlne, isoproterenol, 3meth-oxytyramlne, and oatechd In pH 7.2 buffers on a silver ektrod@ are reported. Catechol and the c a t -are shown to be COordlMted to diver through both oxygens. The methoxylated derlvatlve Is a monodentate complex. Intenskies maximize near -0.9 V vs saturated calomel electrode. The strongest bands In the spwtra are phendic carbon-oxygen stretches and the vlOb modes around 1270 and 1480 cm-l, respectively. Ascorbate, acetylchdlne, glutathione, L-Dopa, and the catecholamine acetlc acid metabolites are SERShracHveunderthemeasuementcondltknr. Dopamkre detectlon lM for the vl Ob band Is 3 X lo-' Y wlth a 10-s measurement tlme.

The band dispersion phenomena in capillary zone electrophoresis (CZE) using untreated and surface-treated open tubular and gel-filled capillaries were experimentally evaluated, with emphasis on small capillary diameters (10-100 microns). Laser-induced fluorescence detection was used for high-sensitivity detection of the isoindoles originated from model amino acids. The plots of plate height vs electric field strength were generated for different column radii and compared with a theoretical model for CZE. In addition to the diffusion-controlled band dispersion in the relatively low electric field range, adsorptive interactions between a solute and the capillary wall may play a certain role in band-broadening. The sorption-desorption kinetics become important with increasing electric field strength. Thermal effects appear to contribute little to band-broadening in relatively small capillaries (less than 50-microns i.d.) within normal operating voltages (less than 30 kV), but could become significant in capillaries with larger bores (greater than 75-microns i.d.). With gel-filled capillaries of small diameters (less than 50-microns i.d.), diffusion processes can be minimized. In addition, thermal effects do not appear critical in such columns at reasonable voltages.

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The surface-enhanced Raman spectroscopy of bilirubin at a silver electrode is investigated in aqueous solution. Bilirubin is found to be adsorbed at the electrode as its dicarboxylate anion. Only one pyrromethenone moiety per molecule contributes to the observed spectrum. SERS from the albumin complex is not observed, suggesting that bilirubin is completely enclosed by this protein.