AWWA WQTC71464

Bromate is commonly formed from the ozonation of bromide in drinking waterand is determined to be a human carcinogen. Currently, bromate is regulatedin drinking water at 10 ug/L. U.S. Environmental Protection Agency (USEPA) Methods 300.1 B, 317.0, and 326.0 areapproved by the USEPA for compliance monitoring. High concentrations ofcommon anions, such as chloride, sulfate, and carbonate, can produce poorbromate peak shapes and lower recoveries. This often requires the analyst toeither dilute the sample which raises the minimum reporting limit (MRL) or pretreatthe sample offline prior to analysis. Pretreatment of samples requiresincreased time and cost for each analysis. Therefore, the objective of this projectwas to develop a method that eliminates high concentrations of matrix ions andminimizes interferences. This paper describes two new USEPA pending methodsusing two-dimensional (2D) ion chromatographic (IC). In the first dimension, alarge loop is injected on a 4-mm high capacity ion exchange column to separatebromate from matrix anions. Bromate is selectively removed using automatedvalve switching onto a concentrator column. In the second dimension, Bromateis separated a second time using a 2-mm anion exchange column followed byquantitation after suppressed conductivity detection. This strategy allows theability to inject large sample volumes, focus bromate partially resolved in the firstdimension onto a concentrator column and separate it on a second, higherresolution column. It also combines two different column chemistries to enhanceselectivity and reduce the possibility of false positives and eliminates the need forsecond column confirmation. This method also improves upon USEPA Method314.0 and 314.1 for the determination of perchlorate in drinking water, even inthe presence of high salt matrices (>1,000 mg/L for Cl^-, SO₄ and NO₃). The newmethod results in a 4-fold signal enhancement, which yields a lower detectionlimit (0.016 µg/L). Includes abstract only.

Product Details

Edition:

Vol. - No.

Published:

11/01/2009

Number of Pages:

1

File Size:

1 file , 740 KB