Hexavalent chromium (Cr6+), a suspected carcinogen, is measured in drinking and wastewater by US EPA method 218.6 and in soils by SW846 method 7199. Both of these methods use anion exchange chromatography followed by diphenyl carbazide (DPC) post column chemistry. This produces a colored complex of Cr6+ which can be detected by UV/VIS using a Metrohm 850 Professional IC with 858 Autosampler and a Lambda 1010 UV/VIS detector achieves detection limits down to 0.2ppb.
Metrohm’s A Supp 10-250 column was used with 10mM LiOH & 7.8mM Li2SO4 as the eluent.
Water samples were analyzed directly and soil samples were extracted using EPA method SW3060A and injected into the ion chromatograph.