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

The potential of a new commercially available microbore anion exchange colu mn for chromium speciation (Cetac ANX-3202) was evaluated and its character istics were studied. Nitric acid was used as mobile phase, making the techn ique ideal for coupling with inductively coupled plasma mass spectrometry ( ICPMS). Because of the low operating flow rate of the column, a microconcen tric nebulizer was used as an interface between the microbore column and th e ICP-mass spectrometer. Co was added to the mobile phase and its signal in tensity was continuously monitored and used as an internal standard to corr ect fur signal drift and instrumental instability. Excellent results were o btained in terms of repeatability. Detection limits for CI(III) and CI(VI) are less than 1 mu g L-1, using either Cr-52 or Cr-53. The accuracy was det ermined by analyzing a certified reference material (BCR CRM 544). The conc entrations found were in good agreement with those certified. The occurrenc e of C- and Cl-based molecular ions was studied and their influence on the determination of chromium was evaluated.