Fractional Determination of Chromium(III) and Chromium(VI) via Ion Chromatography with Inductively Coupled Plasma Atomic Emission Spectrometric Detection

摘要

A technique for the determination of Cr(III) and Cr(VI) species is described which is based on an on-line ion chromatographic separation-inductively coupled plasma atomic emission spectrometric detection (IC-ICPAES). Improved sensitivity and shortened retention time of Cr(VI) are attained by the complex formation of Cr(III) to tetrathiocyanatochromate(III) anion prior to injection and the combined use of a short column (4.0mm I.D.×10 mm) packed with a porous polyacrylate-based anion exchange resin and an eluant of a 5.0×10-4mol dm-3 potassium hydrogen phthalate solution (pH 6.5). The ICPAES is used as a selective detector by observing chromium emission at 283.563nm. Detection limits are 7.5ng for Cr(III) and 22ng for Cr(VI). For a typical sample injection volume of 100mm3 these detection limits correspond to 75ng cm-3 for Cr(III) and 220ng cm-3 for Cr(VI) in concentration This method can be applied to the fractional determination of Cr(III) and Cr(VI) in waste water samples.