Evaluation of a commercially available microbore anion exchange column for chromium speciation with detection by ICP-mass spectrometry and hyphenation with microconcentric nebulization

摘要

The potential of a new commercially available microbore anion exchange column for chromium speciation (Cetac ANX-3202) was evaluated and its characteristics were studied. Nitric acid was used as mobile phase, making the technique ideal for coupling with inductively coupled plasma mass spectrometry (ICPMS). Because of the low operating flow rate of the column, a microconcentric nebulizer was used as an interface between the microbore column and the ICP-mass spectrometer. Co was added to the mobile phase and its signal intensity was continuously monitored and used as an internal standard to correct for signal drift and instrumental instability. Excellent results were obtained in terms of repeatability. Detection limits for Cr(III) and Cr(VI) are less than 1 #mu#g centre dot L~(-1), using either ~(52)Cr or ~(53)Cr. The accuracy was determined by analyzing a certified reference material (BCR CRM 544). The concentrations found were in good agreement with those certified. The occurrence of C- and Cl-based molecular ions was studied and their influence on the determination of chromium was evaluated.