Determination of hexavalent chromium in water by Ion chromatography-mass spectrometry

Objective:A method for the determination of hexavalent chromium in water by ion chromatography-electrospray mass spectrometry was established.Methods: Sample was filtrated by a 0.22 μm micropore filter before injection.The separation of Cr(Ⅵ) was performed on a IonPac AS21 Analytical 2×250 mm column using solution of 20 mmol/L KOH as mobile phase,and the detection of Cr(Ⅵ) was carried out under selected ion monitoring(SIM) mode with monitoring ions of m/z118,117,101,85 and quantative ion of 117.Results: The calibration curve of Cr(Ⅵ) was linear in the range of 0 μg/L～100.0 μg/L with the method detection limit of 0.57 μg/L.The avarge recoveries(n=6) of Cr(Ⅵ) from blank samples spiked with three levels of 4.0 μg/L,10.0 μg/L,50.0 μg/L were 102%,101%,100% respectively,and the corresponding relative standard deviation were 1.27%,2.82% and1.63%.Comparing with the results by spectrophotometry,there was no significant difference.Conclusions: The method is simple,rapid,accurate and highly sensitive.