Spectrophotometric studies and analytical application of gold(III), yttrium(III) and palladium(II) chelates with 7‐(2‐pyridylazo)‐5‐chloro‐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.