Studies on pollutants. III. Analysis of uranium at microgram and milligram levels in waters with N-o-methoxynaphthoyl-N-p-tolylhydroxylamine

A method is presented for rapid liquid-liquid extraction and simultaneous spectrophotometric determination of U(VI) in the presence of various anions and cations which are usually associated with it in water, rocks, minerals, and fission products using N-o-methoxynaphthoyl-N-p-tolylhydroxylamine (MNTHA) in chloroform. The effect of various parameters such as pH, reagent concentration, volume of mother liquor, and foreign ions on the extraction and determination of uranium is discussed. The sensitivity of colorimetric determination of U(VI) with the present method is about 9 times more than the sensitivity of the most sensitive hydroxylamine method reported hitherto. The method is highly selective as it is possible to accomplish separation of uranium from several anions and cations including those of copper, bismuth, iron, lead, thorium, titanium, zirconium, molybdenum, tungsten, lanthanum, and cerium. The overall process of extraction and determination takes approx. 20 min. The method is reproducible and has been applied for the analysis of uranium in lake water. 4 figures, 3 tables