Spectrophotometric Determination of Enzymatically Generated Hydrogen Peroxide Using Sol-Gel Immobilized horseradish Peroxidase

Spectrophotometric Determination of Enzymatically Generated Hydrogen Peroxide Using Sol-Gel Immobilized horseradish Peroxidase

Faida A. M. EL-Essi The determination of aqueous H2O2 at very low concentrations is conveniently done using 4-methoxy -4-aminodiphenylamine as the chromogenic material. When the enzymatically produced hydrogen peroxide is oxidized by the entrapped peroxidase in different Sol-Gel matrices, the preduced oxygen oxidizes the faint blue 4-methoxy -4-aminodiphenylamine into an intense violet colored species. At 550 nm the molar absorptivity of the oxidized chromogen is about 1.45X104 L mol-1cm-1. Activity of entrapped peroxidase was a function in the type of the alkoxysilane percursor. Temperature was found to significantly affect the activity of entrapped peroxidase. The enzyme did not show a decrease in activity for at least two months of use in addition to storage at room temperature and dry conditions for periods exceeding three weeks. Excellent results were obtaind for the determination of glucose in blood serum samples using soluble glucose oxidase in conjunction with the Sol-Gel entrapped peroxidase. Excellent agreement between the results obtained by the proposed method and the widely used standard method, utilizing a commercial reagents kit, was always observed. Faida A. M. EL-Essi Supervisors Dr. Monzir Abdel-Latif Prof. Ali Z. Abu Zuhri Dr. Suliman Al-Khalil 1997 Zajel / An-Najah National University