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.

AN1116 (a) Determination of Hexavalent Chromium Cr(VI) in Drinking Water by Suppressed Conductivity Detection using Dionex IonPac AS11-HC-4µm column.

Instrument Type: IC

Chromates are oxyanions of chromium in the oxidation state of +6. All Cr(VI) compounds are strong oxidizing agents that are considered toxic and potentially carcinogenic. The method described here uses suppressed conductivity detection for the determination of Cr(VI) in drinking water, thus eliminating the post column derivatization used in EPA Methods 218.6 and 218.7. This new approach uses either the Dionex IonPac AS11-HC or AS11-HC-4μm column to separate chromate from other anions in HIW. Even in the challenging HIW sample, the method can easily detect and quantify 2 μg/L Cr(VI).

AN1116 (b) Determination of Hexavalent Chromium Cr(VI) in Drinking Water by Suppressed Conductivity Detection using the Dionex IonPac AS11-HC column.

Instrument Type: IC

Chromates are oxyanions of chromium in the oxidation state of +6. All Cr(VI) compounds are strong oxidizing agents that are considered toxic and potentially carcinogenic. The method described here uses suppressed conductivity detection for the determination of Cr(VI) in drinking water, thus eliminating the post column derivatization used in EPA Methods 218.6 and 218.7. This new approach uses the Dionex IonPac AS11-HC column to separate chromate from other anions in HIW. Even in the challenging HIW sample, the method can easily detect and quantify 2 μg/L Cr(VI).