SPECTROPHOTOMETRIC STUDIES AND APPLICATION ON THE P-TYPE COMPLEX OF Y-CPAPK

The beta-type complex formed between yttrium and p-carboxychlorophosph onazo (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 employ ed, the molar absorptivity was found to be 7.72 x 10(4) l mol(-1) cm(- 1) and the molar ratio of Y-CPApK was 1:2. The linear range was within 2-16 mu g 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 ni ckel-base alloys. The parameters which were related to the formation o f the a-type complex of Y-CPApK were discussed and a comparison of exi sting beta-type complexes between yttrium and the chlorophosphonazo re agents of chromotropic acid was made. (C) 1997 Elsevier Science B.V.