DIFFERENTIAL PULSE POLAROGRAPHIC DETERMINATION OF OSMIUM BY CATALYSIS OF PYROGALLOL-RED BROMATE REACTION

A highly sensitive differential pulse polarographic (DPP) method has been developed for the determination of trace amounts of osmium, based on the catalytic effect of osmium (VIII) on the oxidation of pyrogallol red (PGR) by sodium bromate at pH 7.00 and 25.0 0.1 ? C. The reaction rate was monitored by measuring the differential pulse cathodic current of the oxidation product of PGR and bromate. Various parameters such as the effect of pH, reagents concentrations, time, temperature and interference of a number of cations and anions on the estimation of osmium have been studied to optimize the conditions for determination of osmium. The concentration of osmium in the range of 0.1- 300 ng ml has been determined. The limit of detection was 0.02 ng ml . The precision and accuracy of the method are reported