Analytical applications of the optical properties of ferric hemoglobin: A theoretical and experimental study

Like other hemeproteins, ferric hemoglobin (HbIII) not only can act as a catalyzer in the oxidation of substrates by H2O2 but also can act alone as a H2O2 reducer. In this paper, the kinetic mechanism of the reaction between HbIII and H2O2 is studied, and a mathematical model is developed, which permits the determination of the kinetic constants from the absorbance measurement; the results indicate that each HbIII molecule is able to oxidize up to 5 H2O2 molecules without external regeneration. Second, it is demonstrated that the optical properties of HbIII can also be used as an indicator of this oxidation reaction, and analytical methods can be developed using this approach. A method for H2O2 peroxide determination is presented, which permits the analyte to be determined in a concentration range that depends on the HbIII concentration used and the measurement time, with an RSD better than 5%. In addition, methods for peracetic acid (PPA), the simultaneous determination of PAA + H2O2 and the use of HbIII/H2O2 as an indicator for oxidase enzymatic reactions (glucose/glucose oxidase) are outlined.