AU179: Sensitive Determination of Hexavalent Chromium in Drinking Water

Instrument Type: IC

The work shown here describes modification of the conditions described in EPA Method 218.6, including use of the column in the 2 mm format and a smaller reaction coil to increase method sensitivity. The modified method uses Dionex IonPac AS7 column (2 × 250 mm), a 1000 μL injection volume, and post column reaction (using a 125 μL reaction coil) followed by visible absorbance detection at 530 nm. This method permits an MDL for chromate of 0.001 μg/L. This results in a quantitation limit of 0.003 μg/L, which is more than sufficient for analysis at the proposed California PHG level of 0.02 μg/L.

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.