ELECTROCHEMICAL DETERMINATION AND SPECIATION OF CHROMIUM AT TRACE LEVELS - APPLICATION TO SOIL SAMPLES

An electrochemical procedure for the determination and speciation of chromium species is proposed, based upon the polarographic reduction of chromium(VI) to chromium(III). After optimization of the operational parameters, a detection limit of 17-mu-g/L is achieved. The procedure is specific for chromium(VI) species and, after a previous oxidative step, permits the determination of total chromium, from which the chromium(III) content can be determined by difference, with a detection limit of 23-mu-g/L. The method has been applied to the speciation of chromium in extracts of soils neighbor to a metallic contaminating industry, by means of the Standard Additions Method.