Bromate is commonly formed from the ozonation of bromide in drinking water
and is determined to be a human carcinogen. Currently, bromate is regulated
in drinking water at 10 ug/L. U.S. Environmental Protection Agency (USEPA) Methods 300.1 B, 317.0, and 326.0 are
approved by the USEPA for compliance monitoring. High concentrations of
common anions, such as chloride, sulfate, and carbonate, can produce poor
bromate peak shapes and lower recoveries. This often requires the analyst to
either dilute the sample which raises the minimum reporting limit (MRL) or pretreat
the sample offline prior to analysis. Pretreatment of samples requires
increased time and cost for each analysis. Therefore, the objective of this project
was to develop a method that eliminates high concentrations of matrix ions and
minimizes interferences. This paper describes two new USEPA pending methods
using two-dimensional (2D) ion chromatographic (IC). In the first dimension, a
large loop is injected on a 4-mm high capacity ion exchange column to separate
bromate from matrix anions. Bromate is selectively removed using automated
valve switching onto a concentrator column. In the second dimension, Bromate
is separated a second time using a 2-mm anion exchange column followed by
quantitation after suppressed conductivity detection. This strategy allows the
ability to inject large sample volumes, focus bromate partially resolved in the first
dimension onto a concentrator column and separate it on a second, higher
resolution column. It also combines two different column chemistries to enhance
selectivity and reduce the possibility of false positives and eliminates the need for
second column confirmation. This method also improves upon USEPA Method
314.0 and 314.1 for the determination of perchlorate in drinking water, even in
the presence of high salt matrices (>1,000 mg/L for Cl<sup>-</sup>, SO<sub>4</sub> and NO<sub>3</sub>). The new
method results in a 4-fold signal enhancement, which yields a lower detection
limit (0.016 µg/L). Includes abstract only.
| Edition : | Vol. - No. |
| File Size : | 1
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| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 1 |
| Published : | 11/01/2009 |
