THE SYNERGISTIC CATALYTIC EFFECT OF METAL-CATIONS ON KINETIC REACTIONS AND ITS APPLICATION TO DETERMINATION OF IRON OXIDATION-STATES

Iron(II) and iron(III) catalyzed hydrogen peroxide/chromotropic acid kinetic reactions were studied by the stopped FIA technique. The concept of the synergistic catalytic coefficient (D) was defined. By introducing this coefficient into the previously established procedure for the simultaneous determination of a binary mixture of metal cations in a kinetic reaction, the deviation of the absorbance from the additivity rule could be effectively eliminated, and the linear concentration ranges were enlarged. The selectivity of the kinetic systems, in addition, was also improved remarkably. The iron oxidation states in wastewater and several simulated samples have been determined. The results are satisfactory.