When selenite solutions are determined in the presence of copper using anodic stripping voltammetry (ASV), a new peak appears, which is not associated with copper or selenium. It is attributed to the formation of an intermetallic compound between copper and selenium. To verify the existence of such a compound, cyclic voltammograms have been recorded. It has been shown that there is formation of such a compound, and its composition depends on the copper‐to‐selenite ratio. Copyright © 1994 VCH Publishers, Inc.