Research chemist, Calgon Corp., Pittsburgh, Pa.
Pages: 13 Published: Jan 1981
Characterization of high-purity waters is a classic analytical problem because of lack of sample integrity as well as inaccuracies in the analytical methods employed for measurement. For industrial process water applications, the purity of water with low dissolved solids content has been traditionally determined by on-line monitoring of specific conductance and sodium. Trace concentrations of cations (sodium, potassium, calcium, and magnesium) present in demineralizer effluents, condensates, and high-pressure boiler and boiler feedwaters have been determined by flame or flameless atomic absorption. Previously, there was no accurate method for measuring trace concentrations of anionic constituents. The introduction of a new analytical technique, ion chromatography (IC), has facilitated the identification and quantitation of several anions—chloride, nitrate, orthophosphate, and sulfate at the micrograms-per-litre level. The IC technique incorporates the concepts of ion exchange and conductimetric detection. Without sample pretreatment, these anions can be accurately detected down to about 50 μg/litre with a 100-μl sample injection. By concentrating the anions in the sample on a special low-capacity anion concentrator column (Dionex Corp.) prior to IC analysis, these same anions can be readily detected at <10 μg/litre. The anion concentrator column technique has been applied successfully to the analysis of high-purity waters from various industrial process water systems. The advantages and limitations of the IC method are discussed.
ion chromatography, trace anion analysis, anion concentrator column technique, high-purity waters, industrial process waters, steam, condensate, liquid chromatography, water trace impurities, sequential analysis, conductivity, demineralizers, electric utilities, water treatment, feedwater, water quality, quantitative analysis, instrumentation, power plants
Paper ID: STP28279S