Simultaneous determination of platinum and palladium by second derivative spectrophotometry using 3-(2′-thiazolylazo)-2,6-diaminopyridine as chromophore ligand

A second derivative spectrophotometric method has been developed for the determination of palladium and platinum in mixtures. The method is based on the formation of the platinum and palladium complexes with 3-(2-thiazolylazo)-2,6-diaminopyridine, (2,6-TADAP), in the presence of 1.7 M perchloric acid solution, upon heating at 90 degrees C for 30 min and on the subsequent direct derivative spectrophotometric measurement. The zero-crossing approach and the graphic method were used far determination of platinum and palladium, respectively. Each analyte was determinated in the presence of one another in the ranges 8.9x10(-7) - 3.1x10(-5) M for platinum and 4.6x10(-7) - 6.8x10(-5) M, for palladium. The detection limits achieved (3 sigma) were found to be 2.7x10(-7) M of platinum and 1.4x10(-7) M of palladium. The relative standard deviations were in all instances less than 1.0%. In this work is included a study of effect of interferents and the application of the proposed method in synthetic mixtures.