Sensitive determination of chromium by the catalytic hydrogen wave in the presence of thiocompounds at DME

Abstract

A sensitive polarographic method for the determination of chromium is proposed, based on the catalytic hydrogen wave of Cr VI -xanthate complexes in the presence of NH 4 Cl at mercury electrode. The Cr VI -xanthate complexes produce a catalytic hydrogen wave at -1.52 V vs SCE with potassium propyl xanthate (Kpxan) and at -1.47 V vs SCE with potassium cyclohexyl xanthate (Kchxan) in NH 4 Cl-NH 4 OH medium (pH 9.6 for Kpxan and 9.2 for Kchxan). The peak height is proportional to metal ion concentration. The proposed method is free of interference from other metal ions except Mo VI and is evaluated to micro level Cr VI down to 0.1 ppm by the determination of chromium content in drinking water samples, industrial effluents, tannery waste water and agricultural materials.