Analysis of commercial selenium-supplement tablets.

Commercially available selenium-supplement tablets, obtained from a supermarket and a health food store in several lots were analyzed to compare reported and observed values of total selenium. Atomic absorption spectrometry with a hydride generator was used, and the results were confirmed for selected lots using inductively coupled plasma (ICP) spectrometry. Results indicate more variation than might be suspected. Several lots contained a significantly higher amount of selenium than reported with one lot having 50% more. One brand contained only 20-25% of the reported concentration, a significantly lower amount. Tablets were analyzed and compared to determine which brand, if any, had the most reliable amount per tablet.