Spectrophotmetric Studies and Analytical Application of Au(III), Y(III) and Pd(II) Chelates with 5-choloro-2-pyridylazo-8-hydroxyquinoline

A spectrophotometric study of Au(III), Y(III) and Pd(II) complexes of a reagent 7-(2-pyridylazo)-5-chloro-8-hydroxyquinoline (PACHQ) is presented. Gold(III) forms a 2:1 (L:M) violet complex at pH 9.5 (50% ethanol), while Y(III) and Pd(II) form 2:1 (L:M) red complexes at pH 6.5 and 7.5 respectively. The stability of these complexes has been determined. Beer's law is valid over the concentration range 0-7.87, 0-8.89 and 0-10.64μg ml−1 for Au(III), Y(III) and Pd(II) respectively. A number of foreign ions were tested for their interference. Synthetic solutions identical in composition to some Au(III) and Y(III) alloys are used to ascertain the suitability of the reagent.