Determination of
Selenium(IV) at a Microfabricated Gold Ultramicroelectrode Array Using
Square Wave Anodic Stripping Voltammetry
Sandie H. Tan and Samuel P. Kounaves*
Department of Chemistry, Tufts
University, Medford, MA 02155 U.S.A.
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 curves 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.