KINETIC THERMOMETRIC DETERMINATION OF TRACES OF MANGANESE BY ITS CATALYTIC EFFECT ON THE REACTION BETWEEN TIRON AND HYDROGEN-PEROXIDE

We have developed a highly sensitive kinetic thermometric method for the determination of traces of Mn(II) by its catalytic effect on the oxidation of Tiron by hydrogen peroxide. The reaction is monitored by the initial-rate method, which is applied to temperature-time curves. Under the optimum conditions established in preliminary experiments, manganese can determined over the range 1-120 ng/mL, with an rsd of 5.8% and 1.3% for 5 ng/mL and 40 ng/mL Mn(II), respectively. The proposed method is subjected to few interferences, the most serious of which is posed by Pb(II), with a tolerated ratio of 20:1. The method was satisfactorily applied to the determination of Mn(II) in various types of sample (water, beer and wine).