Determination of Selenium Content in Biologically Active Dietary Supplements and Drinking Water by Anodic Stripping Voltammetry

Abstract The work is devoted to the determination of selenium(IV) content by anodic stripping voltammetry (ASV) with a gold rotating disk electrode (GRDE). The effect of the supporting electrolyte composition on the analytical signal (AS) of selenium is studied and the electrochemical characteristics (deposition potential, potential sweep rate, and deposition time) for recording the anodic current of selenium are optimized. The supporting electrolytes are 4 mM perchloric acid and 3 mM citric acid. A possibility of selenium determination by ASV using a GRDE in 3 mM citric acid is studied for the first time. The relative standard deviation for the concentrations of selenium 10 and 31 μg/L is no more than 5% for both electrolytes (n = 10). Although the sensitivity of the selenium AS in 4 mM perchloric acid is higher than that in 3 mM citric acid, the choice of citric acid as a supporting electrolyte offers a less toxic and more environmentally friendly alternative to perchloric acid. The limits of detection (LODs) calculated using the 3sb/b test are 0.05 μg/L in 4 mM perchloric acid (td = 60 s) and 0.1 μg/L in 3 mM citric acid (td = 90 s), while the limits of quantification (LOQs) calculated using the 10sb/b test are 0.15 and 0.3 μg/L, respectively. The method is applied to determine Se(IV) in a biologically active dietary supplement and in drinking water and demonstrates high accuracy (analytical recovery 96–108%) and rapidity.