Extractive Spectrophotometric Determination of Osmium (VIII) using pmethylphenylthiourea as a Chromogenic reagent: Mutual separation of Palladium, Osmium and Platinum

Simple, rapid and sensitive solvent extraction and spectrophotometric method for the determination of osmium(VIII) using p-methylphenyl thiourea as an analytical reagent has been developed. P-methylphenyl thiourea extracts osmium(VIII) quantitatively into chloroform from 0.45 mol L^-1 perchloric acid medium. The chloroform extract shows an intense peak at 512 nm (λ max). The method is applicable over wide Beers range (upto 60 μg mL^-1).The molar absorptivity and sandell’s sensitivity for Os (VIII)-PMPT system is 6.83 x 10^3 L mol^-1cm^-1 and 0.028 μg cm^-2 respectively. The composition of complex is found to be 1:1(Os (VIII): PMPT) by slope ratio, mole ratio and job’s continuous variation methods. Interference by various ions has been studied. The proposed method has been successfully employed for determination of Os(VIII) in synthetic samples. Mutual separation of palladium(II), osmium(VIII) and platinum(IV) is carried out using proposed method.