Spectrophotometric studies and application on the -type complex of Y-CPApK

The β -type complex formed between yttrium and p -carboxychlorophosphonazo (CPApK) has been studied. It was found that Y-CPApK complex can give a maximum absorptivity in a buffer media of HAc–NaAc ranging from pH 3.5–4.3 and at a wavelength of 732 nm. Under the conditions employed, the molar absorptivity was found to be 7.72×10 4 l mol −1 cm −1 and the molar ratio of Y-CPApK was 1:2. The linear range was within 2–16 μg of yttrium in 25 ml solution. One of the characteristics of the complex was its high tolerance for calcium and hence a method of separation and enrichment of microamounts of yttrium by using calcium oxalate precipitate was developed and applied to measure yttrium in nickel-base alloys. The parameters which were related to the formation of the β -type complex of Y-CPApK were discussed and a comparison of existing β -type complexes between yttrium and the chlorophosphonazo reagents of chromotropic acid was made.