1.5th-Differential polarographic determination of trace amounts of selenium(IV) and selenium(VI) in natural waters at a dropping mercury electrode

Abstract

This paper describes a polarographic method for the determination of trace amounts of Se^IV and Se^VI in natural waters using a dropping mercury electrode. In an HClO₄-Na₂SO₃-NH₃-NH₄Cl-NH₂OH.HCl-KlO₃ system (pH 10), the selenium complex SeSO₃^2– gave a peak potential at –0.57 V versus Ag. The peak current was directly proportional to Se in the concentration range 0.01–1 µg l^–1. The limit of detection was 10 ng l^–1. The proposed method is rapid, simple, sensitive and accurate. The recovery of Se from standard additions to samples of natural waters was between 93 and 105%.