Simultaneous first derivative spectrophotometric determination of palladium and nickel using 2-(2-thiazolylazo)-5-dimethylaminobenzoic acid as an analytical reagent

A simple, rapid, selective, sensitive and economical method has been developed for the simultaneous determination of trace amounts of palladium and nickel in aqueous methanolic medium using 2-(2-thiazolylazo) -5-dimethylaminobenzoic acid as an analytical reagent by first derivative spectrophotometry. Palladium is determined by measuring base to peak distance at lambda = 695.0 nm while nickel is estimated by zero crossing method in the mixture. The linearity is maintained between 0.12-1.75 mu g mL(-1) for palladium and 0.07-1.60 mu g mL(-1) for nickel in the pH range 2.8-7.2 and 3.4-8.8 respectively. Seven replicate determinations of 1.0 mu g mL(-1) of palladium and 0.8 mu g mL(-1) of nickel in a mixture give a mean signal height of 0.391 for Pd and 0.541 for Ni with relative standard deviations of 0.9% and 1.2%, respectively. The sensitivity of the proposed method is 0.391 (dA/d lambda)/ (mu gmL(-1)) for palladium and 0.685 (dA/d lambda)/ (mu gmL(-1)) for nickel. Various parameters have been optimised for the simultaneous determination of palladium and nickel in various complex samples.