Separation and determination of Cr(III) by titanium dioxide-filled column and inductively coupled plasma mass spectrometry

A fast, sensitive, and selective method for the separation and determination of chromium species in natural waters using TiO2-filled column coupled to ICP-MS was developed. At pH 2, Cr(VI) was retained in the column, while Cr(III) was eluted and detected by the on-line inductively coupled plasma mass spectrometer (ICP-MS). The concentration of Cr(VI) was calculated by the difference between the total chromium concentration, which was determined directly, and the concentration of Cr(III). The developed method was especially suitable for the determination of chromium species in natural waters when standard addition was used for calibration. The detection limits for Cr(III) and Cr(VI) at m/z 52 were 0.08 and 0.07 mug/l. The relative standard deviations at 0.27 mug/l Cr(III) and 0.23 mug/l Cr(VI) were 4.4 and 3.4%, respectively. Furthermore, the developed method was verified by analyzing certified reference materials NWRI TM-23, TM-24, and TM-26. The concentrations of cr(III) were found to be 6.6 +/- 0.4, 5.6 +/- 0.6, and 11.3 +/- 0.4 mug/l respectively. (C) 2001 Elsevier Science B.V. All rights reserved.