Direct spectrophotometric determination of gold(III) using 2-aminoacetophenone isonicotinoyl hydrazone (2-AAINH)

Department of Chemistry, Sri Krishnadevaraya University, Anantapur-515 003, India Fax : 91-8554-29043 Manuscript received 20 May 2003, revised 13 November 2003, accepted 14 January 2004 A simple, highly sensitive and specific spectrophotometric method has been developed for the determination of gold(III) in aqueous dimethylformamide (DMF). The metal ion reacts with 2-aminoacetophenone isonicotinoyl hydrazone (2-AAINH) forming a reddish brown complex in the pH range 3.0-6.0. The complex shows maximum absorption at 440 nm. Beer's law is obeyed in the range 0.400-5.00 )µg ml-1. The molar absorptivity and Sandell's sensitivity are 3.50 x 104 mol3 cm-1 cm-1 and 0.0056 µg Cm-2, respectively. Job's method indicates the formation of two complex species. The stahility constants corresponding to these maxima were determined and found to be 9.6 x 1015 (1 : 3, M : R) and 4.45 x 1012 (2 : 1, M : R). The method has been employed successfully for the determination of gold(lll) in pharmaceutical samples