Sol–gel horseradish peroxidase biosensor for hydrogen peroxide detection by chemiluminescence

Horseradish peroxidase (HRP) was immobilized by microencapsulation in sol–gel crystals derived from tetramethyl orthosilicate. A sol–gel biosensor based on the chemiluminescence reaction of the hydrogen peroxide–luminol–HRP system was developed. Calibration plots for hydrogen peroxide have been established by chemiluminescence measurements in a cuvette and through an optical fibre modified at its end with the immobilized HRP gel. The detection limit was 6.7×10−4 M and the linear range was 0.1–3.0 mM. The relative standard deviation was 7.1% (n=4). This method was applied to hydrogen peroxide determination in disinfectant solutions for contact lenses.