Determination of Common Inorganic Anions in Environmental Waters Using a Hydroxide Selective Column

ulatory standard for minimizing potentihealth effects arising from their ingestion in drinking water (5). Other common inorganic anions, such as fluoride, chloride, and sulfate, are considered secondary contaminants and are regulated under the U.S. National Secondary Drinking Water Standards, which are guidelines for taste, color, odor, and certain aesthetic effects (6). Although bromide is not regulated under these standards, it is a precursor to bromate, which is regulated under the NPDWS, and therefore, most water-supply systems are required to analyze for bromide. Many of the other countries previously mentioned have health standards similar to the United States for the anions specified. Since the mid-1980s, IC has been approved for compliance monitoring of these inorganic anions in drinking water, as described in EPA Method 300.0 Part A (7). In 1992, this same method was recommended for promulgation by the EPA-Environmental Monitoring Systems Laboratory (EMSL, Cincinnati, Ohio) for compliance monitoring in all EPA regions for the determination of inorganic anions in wastewater under the National Pollution Discharge Elimination System Program (4). EPA Method 300.0 Part A describes the use of an IonPac AS4A anion-exchange column The United States Environmental Protection Agency (EPA) Office of Water has determined that the use of hydroxide eluents in EPA Methods 300.0 and 300.1 is acceptable for compliance monitoring of common inorganic anions by ion chromatography under the Clean Water Act (CWA) and the Safe Drinking Water Act (SDWA). The authors evaluated the performance of a high-capacity anion-exchange column specifically designed for use with hydroxide eluents for fulfilling the requirements of EPA Method 300.0 Part A and compared the results with data generated with an anion-exchange column using carbonate eluents. The high-capacity anion-exchange column used with an on-line electrolytically generated potassium hydroxide eluent yielded improved calibration linearity (r2 . 0.999), improved retention-time stability (, 0.05% RSD for most anions), and comparable or better method detection limits. Determination of Common Inorganic Anions in Environmental Waters Using a Hydroxide Selective Column