Kinetic Studies of the Promoting Effect of Glutaraldehyde on the Oxidation of p-Phenylenediamine by Hydrogen Peroxide

Article abstract of DOI:10.1021/ac00278a046

Glutaraldehyde accelerates the oxidation of p-phenylenediamine by hydrogen peroxide, and this effect has been used for the "catalytic" detection of aldehyde groups and for the determination of these groups on the surface of modified (by glutaraldehyde) aminosilane glass to be used for protein immobilization.A reexamination of the effect of glutaraldehyde (25 deg C, 1.00 M ionic strength, and pH 5.00) has demonstrated that the unprotonated form of p-phenylenediamine is the reactive species, that glutaraldehyde acts as a promoter and not as a true catalyst, and that once formed the product of the reaction (Bandarowski's base) is destroyed by further reaction with hydrogen peroxide.An empirical reaction model of the oxidation was analysed by computer, and satisfactory reproduction of experimental data suggests three regions in the overall reaction profile: (1) early periods of reaction in which the predominant process is the conversion of p-phenylenediamine to Bandarowski's base by a complex formed between glutaraldehyde and hydrogen peroxide, (2) an intermediate region in which the uncatalyzed oxidation also becomes a significant contributor to the overall rate, and (3) late reaction times when the destruction of Bandarowski's base by hydrogen peroxide dominates.