Determination of the common anions such as bromide, chloride, fluoride, nitrate, nitrite, phosphate, and sulfate often is desirable to characterize a water and to assess the need for specific treatment. In addition, the need to measure the concentration of the disinfection by-products chlorite, chlorate, and bromate has arisen. Although conventional colorimetric, electrometric, or titrimetric methods are available for determining individual anions, ion chromatography provides a single instrumental technique that may be used for their rapid, sequential measurement. Ion chromatography eliminates the need to use hazardous reagents and it effectively distinguishes among the halides (Br−, Cl−, and F−) and the oxyhalides (ClO2−, ClO3−, and BrO3−), and the oxy-ions (PO43−, SO42−, NO2−, and NO3−).
Methods 4110 B and 4110 C are applicable (after filtration to remove particles larger than 0.45 μm) to surface, ground, wastewaters, and drinking water. Some industrial process waters, such as boiler water and cooling water, also may be analyzed by this method. Method 4110 D is applicable to untreated and finished drinking water as well as drinking water at various stages of treatment.