INTERACTION STUDY OF THE CARMINIC ACID WI TH URANYL-ION

A spectrophotometric study of interaction of uranyl ion with carminic acid (AC) is presented and the effect of different variables (pH, conc entration of AC, etc.) on the complexation reaction was studied. Two c omplexes are formed, one greenish and other purple; the first is forme d at a value of pH 3.7 within a M:L relationship 1:2, while the purple is formed to pH 5.7 within a M:L relationship 1:4. The apparent forma tion constants of both complexes were calculated. A spectrophotometric method of determination of uranyl ion with AC, was developed. The use ful concentration interval was 2 to 50 ppm. The green complex was obta ined in solid state and was characterized, and the stoichiometric M:L = 1:2 was confirmed. The coordination of uranyl ion is carried out by the oxygens of the carboxylic acid groups present in the carminic acid molecules.