Determination of Chromium(III) and Chromium(VI) by Electrothermal Atomization Atomic-Absorption Spectrometry Following Coprecipitation with Gallium(III) Phosphate

Abstract

Abstract Gallium(III) phosphate coprecipitates quantitatively 0.2—7.5 μg of chromium(III) from 100 to 500 cm3 of a sample solution at pH 4.5—6.0. Although chromium(VI) is hardly coprecipitated with gallium(III) phosphate, it can be collected as chromium(III) after reduction by hydroxylamine. The calibration curve is linear from 8 to 300 ng cm−3 for chromium. The detection limit (signal/noise = 2) is 0.11 ng cm−3 of chromium(III) or chromium(VI) in 500 cm3 of the initial sample solution.