K. Cheng
Jun 1, 1958
Citations
0
Influential Citations
66
Citations
Journal
Analytical Chemistry
Abstract
1-(2-Pyridylazo)-2-naphthol reacts with many polyvalent metals, forming intensely colored complexes. However, in the presence of strong complexing agents, such as (ethylenedinitrilo)tetraacetic acid and cyanide, it reacts only with uranium to form a deep red finely divided precipitate in ammoniacal solutions. The naphthol complex can be exracted by o-dichlorobenzene and has its maximum absorption at 570 m mu . The color is stable and follows Beer's law over the range of 0.1 to 5 a 10/sup -4/ mmole of uranium in 10 nd of the solvent. The molar absorptivity of 1-(2-pyridylazo)-2-naphthol is 23,000; therefore, it may be the most sensitive color reagent for uranium. Trace amounts of uranium may be determined in the presence of many metals without prior separation. (auth)