Polarographic Studies on the Hemoglobin Mimetic Peroxidase Catalytic Reaction System

Based on the catalysis of hemoglobin (Hb) to the oxidation of o-phenylenediamine (OPD) with H_(2)O_(2), a new polarographic method is proposed for the determination of Hb and (H_(2)O_(2)). Hb possessesthe similar functional structure as peroxidase and can be used as catalyst in this oxidation reaction. The oxidative product has a well-defined second order derivative reductive peak at -0.64V (vs.SCE). The conditions for catalytic reaction and polarographic detection have been carefully studied. At the optional conditions, Hb can be detected in the linear range from 2.0×10~(-9 )mol/L to 2.0×10~(-7)mol/L with the detection limit of1.0×10~(-9)mol/L. This new method can also be applied to the detection of H_(2)O_(2 )with the linear range of1.0×10~(-6)～2.0×10~(-4 )mol/L with detection limit of1.0×10~(-6)mol/L.