[Determination of hexavalent chromium in atmospheric particles PM2.5 and PM10 by ion chromatography with inductively coupled plasma mass spectrometry].

An analytical method using ion chromatography with inductively coupled plasma mass spectrometry (IC-ICP-MS) for the determination of hexavalent chromium (Cr(VI)) in atmospheric particles PM2.5 and PM10 was established. The Cr(VI) in the atmospheric particles was extracted ultrasonically with sodium bicarbonate solution. An anion exchange column (AG7, 50 mm x 4 mm) with 75 mmol/L ammonium nitrate solution (containing 0.22 g/L Na2EDTA, pH 7.0) as mobile phase was used for the separation. ICP-MS was used as a detector for the determination of hexavalent chromium. The calibration curve was linear in the range of 0.05-5 μg/L and the correlation coefficient was 0.999 9 for Cr(VI). The cellulose filter was fit for sampling. With the alkaline cellulose filter, the recovery of Cr(VI) increased from 75% to 102%. The recovery was complete and stable when the samples were sonicated in 20 mmol/L sodium bicarbonate solution for 30 min. The limit of quantification (LOQ) of Cr(VI) was 0.000 4 ng/m3 when the sampling volume was 20 m3. The average recoveries of Cr(VI) in the spiked PM2.5 and PM10 samples ranged from 91.6% to 102% with the relative standard deviations not more than 7.6%. The method is efficient and reliable. It can meet the requirement for the determination of Cr(VI) in atmospheric particles.