TN26: Determination of Cr(VI) in Water, Wastewater, and Solid Waste Extracts

Instrument Type: IC

The method presented here overcomes analyte interference by separating the two chromium using a detection method specific for Cr(VI) that is capable of handling the high-ionic-strength sample matrices generated in many leaching, and digestion procedures. Cr(VI) is separated as the divalent anion on the IonPac AS7 column using ammonium sulfate, ammonium hydroxide eluent. After the separation, Cr(VI) reacts with the color reagent diphenylcarbohydrazide (DPC) and detected by UV absorbance at 520 nm. This method is consistent with U.S. EPA Method 218.6. Please refer to AU179 for an updated method.

AU144: Determination of Hexavalent Chromium in Drinking Water Using Ion Chromatography.

Instrument Type: IC

Hexavalent chromium, Cr(VI), is the most toxic form of chromium, a primary drinking water contaminant in the U.S. Cr(VI) can be determined as chromate by ion chromatography in drinking water, and wastewater.The California Department of Health Services recently issued a new Public Health Goal of 0.2 µg/L for Cr(VI). EPA Method 218.6 does not allow sufficient sensitivity for analysis at the California PHG level. This update describes modifications to Method 218.6 that significantly increase sensitivity over the existing method.Also refer to AU 179 for an updated method.