DETERMINATION OF SELENIUM(IV) AT A MICROFABRICATED GOLD ULTRAMICROELECTRODE ARRAY USING SQUARE-WAVE ANODIC-STRIPPING VOLTAMMETRY

The voltammetric determination of selenium(rv) using a microfabricated array of gold ultramicroelectrodes (Au UMEs) is presented. The array of Au UMEs in conjunction with square wave anodic stripping voltammetr y shows a rapid, sensitive and reproducible response for selenium. Usi ng an array of UMEs overcomes the inherent disadvantage of measuring t he very low current signals present when using a single UME. The exper imental parameters that affect the response of selenium: deposition po tential, selection of the electrolyte solution, SW frequency, and depo sition time were investigated. The Se redox reaction appears to be kin etically faster and more reversible at the An UME array than at Au mac roelectrode or single Au UME. Calibration plots are given for solution s containing 0-100 ppb and 100-500 ppb. The limit of detection is calc ulated to be 0.42 ppb. The relative standard deviation at 50 ppb is 4. 5 % for 10 runs.