Spectrophotometric determination of palladium in catalysts and carbenicillin with 1-(2-pyridylmethylidene)-5-(salicylidene)-thiocarbohydrazone

Abstract

A selective and sensitive method is described for the spectrophotometric determination of palladium using 1-(2-pyridylmethylidene)-5-(salicylidene)thiocarbohydrazone reagent. The orange complex is formed in pH 8.3 EDTA-bicine-borate buffer in a medium containing 32%V/V dimethylformamide, and the absorbance is measured at 505 nm. The molar absorptivity is 16 500 l mol^–1 cm^–1, and in the determination of 0.75 µg ml^–1 of palladium the relative standard deviation is about 2%. The effect of interferences was studied and the selectivity of the reaction was enhanced by using appropriate masking agents. The method was applied to the determination of palladium in synthetic mixtures, hydrogenation catalysts and carbenicillin (semi-synthetic penicillin).