| Abstract
| - The electrochemical oxidation of dissolved azide anion hasbeen investigated at the basal plane of highly orientedpyrolytic graphite. Cyclic and linear sweep voltammetryand differential pulse voltammetry were employed to studythe oxidation reaction mechanism in neutral pH as afunction of the potential sweep rate, analyte concentration,and electrolyte composition and in the presence of adsorbed anthraquinone-2,6-disulfonate (2,6-AQDS). Thelinear dynamic range in the differential pulse voltammetricmeasurements was 4 orders of magnitude and the estimated limit of detection (SNR = 3) was ∼2.3 × 10-7 M(9.7 ppb). The electron-transfer kinetics for azide oxidation appear rapid at this surface, and the voltammetricfeatures are independent of the fraction of exposed edgeplane, the presence of surface oxides, the electrolytecomposition, and the adsorption of 2,6-AQDS. The reaction is shown to proceed by an EC(dim) mechanism.Amperometric detection results for flow injection analysis(FIA) and ion chromatography are also presented. A lineardynamic range of nearly 5 orders of magnitude, anestimated detection limit (SNR = 3) of 3.7 nM (0.16 ppbor 74 fmol injected), and a response variability of 2% orless were observed in the FIA measurements.
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