Reagents for determination of trace impurities in water

Determinations of trace impurities, pollutants, in water are often complicated by a large number of factors which consume a great deal of time. Thus, ideal reagents --- sensitive, specific, stable, water-soluble reagents --- are needed for rapid, spectrophotometric determinations of trace impurities in water. Syntheses, purifications, and characterizations of the naphthol-mono-sulfonic acids are described. In addition, data essential to the quantitative evaluation of various naphthosulfonic acids is presented. A new method for the determination of nitrate in water is described; the proposed method, which uses 2-nitroso-1-naphthol-4-sulfonic acid, is much more rapid than the presently accepted standard methods for determination of nitrate. Another method, which uses 1-naphthol-4-sulfonic acid for the determination of nitrate and proposed by another worker has been carefully and critically evaluated and found to be satisfactory only under very carefully controlled conditions . A new reagent, sodium 2-nitroso-1-naphthol-5-sulfonate, has been proposed for the rapid, specific, sensitive determination of cobalt in natural waters. Full development of water resources, and the control of pollutants returned to natural-water systems, are dependent upon methods of determining trace constituents; significant contributions toward meeting those needs have been accomplished in this work. The methods can readily be applied to such diverse systems as lakes where agricultural fertilizer run-off may be significant, to effluents from plants in the metallurigical industry, to natural-water systems in highly mineralized areas, and to run-off from strip-mined lands. Effective new research areas are readily identified as an extension of the work reported here; better methods for the determination of nitrate in water, and more sensitive methods for the determination of cobalt in water are envisioned.U.S. Department of the InteriorU.S. Geological SurveyOpe