A fully automated total metals and chromium speciation single platform introduction system for ICP-MS†
Measuring chromium species in drinking water has become of particular interest due to daily environmental contamination that is caused by industrial processes. Agencies such as the US Environmental Protection Agency and the European Union continue to investigate the maximum to which Cr(VI) contaminant levels should be set; thus laboratories must seek more efficient ways of performing routine analyses. In this work a single platform, automated speciation and total metals method is presented for chromium speciation in drinking water, waste water, industrial waters, and recipient waters, and for total metals in sludges, soils, organic waste, ashes, biological samples, or paint. Samples were measured using a prepFAST IC system for Cr(III) and Cr(VI) and the results were compared to the HPLC results. In addition, samples from the aqua regia total method were compared to those of the total metals method performed using the prepFAST IC. Sample comparisons resulted in linear regression plots with very good correlations, greater than 0.97 for total metals over a dynamic range of 0.010–100 000 μg L−1 for 63 elements and greater than 0.98 for Cr(VI) speciation. The limits of detection for Cr(VI) and Cr(III) using the prepFAST IC and ICP-MS combination are 7 ng L−1 and 12 ng L−1, respectively. The new method resulted in an ∼43× improvement in detection limits as compared to the previous method employed in our laboratory. The accurate results for quality control samples of Cr(VI) were in good agreement with the historical values collected using the old method.