Interaction of uranium(6) with antipyrine dyes

Uranyl-ion interaction with some antipyrine dyes (chrompyrazole (CP), chromethylpyrazole) was studied and the technique of its direct photometric determination with CP was elaborated on the basis of the mentioned study. The optimal conditions of formation of the colored colloid solution of the ion associates of uranyl thiocyanate acidocomplexes with protoned forms of the antipyrine dyes for CP were as follows: 3 mole/l of HCl; 0.5 mole/l of NH4SCN; total concentration of U(6) and of dyes was equal to 4.10-4 mole/l. Increase of temperature up to 40-50 deg accelerated essentially the process of complex formation. Uranyl-ion:CP ratio in complex constituted 1:4. It was possible to determine U(6) in the presence of 100-fold mole excesses of thorium, zirconium, rare-earth elements, titanium, while tin and molybdenum retarded U(6) determination