Determination of Hexavalent Chromium in Soil Sampres by Ultrasound-assisted Extraction Ion Chromatography

An ultrasound-assisted ion chromatographic method was developed for the determinination of hexavalent chromium in the chromium contaminated sites.Using 0.3 mol/L KC1 solution as extractant,12 soil samples were treated by ultrasonic assisted extraction for 20 min.The sample was analyzed on a Metrosep A Supp 4-250(250 mm×4.0 mm) anion separation column,using a mixture of 4 mmol/L Na_2CO_3-1 mmol/L NaHCO_3 as eluent.The method showed a good linearity(r~2= 0.999 8) in the range of 0.01-20 mg/L for the hexavalent chromium.The detection limit was 0.003 mg/L,the spiked recoveries were in the range of 96.4%-106.8%with RSDs(n=3) of 0.56%.The method was simple,rapid and accurate,and was suitable for the investigation on the chromium contaminated sites.