Determination of Selenium(IV) at a Microfabricated Gold Ultramicroelectrode Array Using Square Wave Anodic Stripping

The voltammetric determination of selenium(IV) using a microfabricated array of gold ultramicroelectrodes (Au UMEs) is presented. The array of Au UMEs in conjunction with square wave anodic stripping voltammetry shows a rapid, sensitive and reproducible response for selenium. Using an array of UMEs overcomes the inherent disadvantage of measuring the very low current signals present when using a single UME. The experimental parameters that affect the response of selenium: deposition potential, selection of the electrolyte solution, SW frequency, and deposition time were investigated. The Se redox reaction appears to be kinetically faster and more reversible at the Au UME array than at Au macroelectrode or single Au UME. Calibration plots are given for solutions containing 0–100 ppb and 100–500 ppb. The limit of detection is calculated to be 0.42 ppb. The relative standard deviation at 50 ppb is 4.5 % for 10 runs