Scanning potential stopped-rotation voltammetry

Abstract

The technique of scanning potential stopped-rotation voltammetry, which is based on measuring the differences between currents with the electrode rotation switched on and off while the applied potential is scanned linearly, is described. Asymmetric rotation pulses, without the achievement of the rotation “off” steady-state current, are employed. The resulting modulated response is free of most background current components, directly proportional to the analyte concentration and reproducible. Well defined current-potential graphs are obtained for ascorbic acid, dopamine, homovanillic acid and hexacyanoferrate(II) ion at the micromolar concentration level. Extremely low background signals are achieved at a glassy-carbon disk electrode, allowing a detection limit of 7 × 10^–8M of dopamine. The technique is simple and suitable for automation.