RESUMEN
Health effects studies suggest that bromate should be regulated at 0.5 microgram/l or less in drinking water. Accordingly, an analytical method is needed to quantify this contaminant with great sensitivity and selectivity. Past efforts to do this have focused on pre-concentration ion chromatographic (IC) separation followed by suppressed conductivity detection. Interfering chloride was removed by passing samples over a silver resin which increased sample analysis time to almost 1 h. In this paper, a new method which uses IC separation with no pre-treatment followed by a post-column reaction to produce tribromide (Br3-) from bromate, is applied to the analysis of a variety of aqueous samples. The tribromide ion is detected by UV absorbance at 267 nm. This method is very sensitive for bromate with a limit of quantitation of 0.2 microgram/l and is also very selective. Common anions typically separated by IC exhibit no interference, even at the levels normally found in drinking water.
Asunto(s)
Bromatos/análisis , Cromatografía por Intercambio Iónico/métodos , Agua Dulce/química , Contaminantes del Agua/análisis , Abastecimiento de Agua/análisis , Sensibilidad y Especificidad , Espectrofotometría UltravioletaRESUMEN
Disinfection byproduct anions such as bromate, chlorite and chlorate pose significant health risks, even at low microgram/l levels in drinking water. A direct injection, ion chromatographic method was developed using a Dionex AS9-HC anion-exchange column with a carbonate eluent and suppressed conductivity detection for the determination of these disinfection byproduct anions, and bromide, at low microgram/l levels in drinking water. No additional sample pretreatment, other than filtration, is required. The method is linear for the oxyhalides and bromide over the typical concentration range expected for these analytes in drinking water; and quantitative recoveries were obtained for drinking water samples spiked at 10 micrograms/l. This ion chromatographic method, based on the recently developed AS9-HC column, is applicable for the quantitation of bromate in finished drinking water at the 10 micrograms/l maximum contaminant level currently being proposed by the US EPA.