Rapid sequential determination of chromium(III)-chromium(VI) by flow injection analysis-inductively coupled plasma atomic-emission spectrometry
Abstract
A rapid and sensitive method for the sequential determination of Cr(III)-Cr(VI) based on flow injection analysis-inductively coupled plasma atomic-emission spectrometry (FIA-ICP-AES) has been developed. A micro-column of activated alumina was used in the FIA manifold to separate and pre-concentrate Cr(VI) from Cr(III) in synthetic aqueous solutions before ICP detection at 267.72 nm. Linear calibration for Cr(III) and Cr(VI) was established over the concentration range 0–1000 µg l–1. The relative standard deviations at the 10 µg l–1 level for a 2-ml sample injection were 2.2% for Cr(III) and 1.1% for Cr(VI) and the corresponding limits of detection were 1.4 and 0.20 µg l–1, respectively. Determinations of Cr(III) and Cr(VI) at the µg l–1 level in reference waters of the National Bureau of Standards and the British Geological Survey were demonstrated.