Characterization of ABTS at a polymer-modified electrode

2:2'-azinobis (3-ethylbenzothiazoline-6-sulfonate), a colorless dianion that forms a colored radical upon oxidation. was characterized with electrochemistry and spectroscopy and demonstrated to be a detectable analyte in a polymer-modified spectroelectrochemical sensor. Three positively charged polymers were incorporated into a thin film on an indium tin oxide (ITO) optically transparent electrode and used to concentrate ABTS at the electrode surface. Of the three films, poly(vinylbenzyl trimethyl ammonium chloride)-poly(vinyl alcohol) (PVTAC-PVA), poly(diallyldimethylammonium chloride)-silica (PDMDAAC-SiO2), and quaternized poly(4-vinyl-N-methylpyridinium nitrate)-silica (QPVP-SiO2), PVTAC-PVA demonstrated the best ability to absorb ABTS. Within 20 min, a change of 0.2 absorbance units at 417 nm and 13.6 muA/cm(2) in anodic peak current density in cyclic voltammetry at a scan rate of 0.025 V/s were observed.