Removal of interferences in the speciation of chromium using an octopole reaction system in ion chromatography with inductively coupled plasma mass spectrometry

When inductively coupled plasma mass spectrometry (ICP-MS) is used for the detection of 52 Cr (83.8%) species in ion chromatography (IC) interference from polyatomic ions such as (ArC+)-Ar-40-C-12 and (ClOH1)-Cl-35-O-16-H-1, often occurs due to their mass at m/z 52. To address the issue, an octopole reaction system (ORS) in ICP-MS, including He and H-2 modes, was used to determine whether the background and interference from polyatomic ions could be reduced in the detection of Cr-52. Compared to standard mode, the polyatomic ions were reduced by either He or H-2; for example, more than 97 and 98% of Cl-35 was removed using a He and H-2 tune, respectively. However, the detection sensitivity for Cr-52 was decreased, for example, the sensitivity was 27.95 and 67.02% of the standard mode for Cr(EDTA)(2)(-) using a He and H-2 tune, respectively. The H-2 tune is recommended for the detection of Cr-52 at a flow rate of 2.0 mL/min with detection limits in the range of 0.2-0.4 mu g/L. The developed method was used to measure chromium speciation in waters containing high concentration of chloride. (c) 2007 Elsevier B.V. All rights reserved.