Determination of chromium (III) in natural water samples utilizing capillary micro-extraction on nanometre zirconium phosphate coating coupled to electrothermal atomic absorbance spectrometry

A simple and sensitive method for the separation of Cr(III) in natural water was developed. The novel method was targeted on extraction of Cr(III) by using a nanometre-scale zirconium phosphate coated capillary tube, and determined by electrothermal atomic absorption spectrometry (ETAAS). The variables influencing the micro-extraction of Cr(III) including pH, sample volume, sample flow rate, eluent volume and eluent flow rate were investigated. Under the optimized conditions, the detection limit (3s) was 0.042 ng mL(-1), and the relative standard deviation (RSD) was 1.5% (c = 10 ng mL(-1), n = 7). The proposed method was applied to determination of Cr(III) in natural waters.