Kinetic and Analytical Characteristics of the Peroxidase Oxidation Reaction of Sodium Triphenyl-4-Sulfonate

We studied a possibility of the enzymatic oxidation of sulfo derivatives of di- and triarylamines with hydrogen peroxide in the presence of horseradish peroxidase (HRP). The product of the enzymatic oxidation of sodium triphenylamine-4-sulfonate (TPAS) is more stable than sodium diphenylamine-4-sulfonate. The effects of various factors, such as the nature of buffer solutions, reagent concentrations, and the presence of cationic Ir(IV) and Rh(III) complexes in the reaction medium, on the TPAS oxidation rate were studied. The kinetic regularities of the TPAS enzymatic oxidation were studied, the kinetic parameters ( k cat , K M ) were estimated, and an assumption was made about the process activation mechanism in the presence of catalytically active Ir(IV) and Rh(III) complexes. The reaction of the enzymatic oxidation of TPAS can be used for the determination of HRP (5.0 × 10 –2 nM), hydrogen peroxide (0.6 mM), and cationic complexes of Ir(IV) (5 nM) and Rh(III) (60 nM).