Electroluminescent detection of enzymatically generated hydrogen peroxide

The present work studies the analytical possibilities of the electroluminescent detection of hydrogen peroxide generated in an enzymatic reaction. Glucose oxidation through the enzyme glucose oxidase (GOD) was used as the study system. The hydrogen peroxide generated reacts in situ with the radical obtained by electrochemical oxidation of luminol (5-amino-2,3-dihydrophthalazine-1,4-dione) on a glassy carbon electrode. The detection limit (2 x background noise) was 4.3 x 10(-6) M. The variables affecting the electroluminescent detection of hydrogen peroxide in the enzymatic reaction were studied. A linear calibration range of 5-50 mu g ml(-1) glucose was achieved. The proposed system was applied to the determination of glucose in different types of fruit juice and human serum. A dialysis membrane was coupled to the flow system in order to avoid electrode fouling, giving a linear calibration range of 50-300 mu g ml(-1).