Water-soluble fluorescent conjugated polymer-enzyme hybrid system for the determination of both hydroquinone and hydrogen peroxide

In this paper, a sensitive and simple detecting system was developed for quantitative analysis of both hydroquinone (H2Q) and hydrogen peroxide (H2O2), based on the successful combination of horse radish peroxidase (HRP) and water-soluble conjugate fluorescence polymers PPESO3. In the presence of HRP and H2O2, H2Q could be oxidized to 1,4-benzoquinone (BQ), an intermediate, which plays the main role in the enhanced quenching of the photoluminescence (PL) intensity of PPESO3. The quenching PL intensity of PPESO3 (I0/I) was proportional to the concentration of H2Q and H2O2 in the range of 1.0 × 10−6 to 2.0 × 10−3 mol/L (R2 = 0.996) and 6.0 × 10−6 to 2.0 × 10−3 mol/L (R2 = 0.999), respectively. The detection limit for H2Q and H2O2 was 5.0 × 10−7 mol/L and 1.0 × 10−6 mol/L, respectively. The present fluorescence quenching method was successfully applied for the determination of H2Q in the lake water, rainwater, tap-water and chemical plant wastewater samples. Compared with previous reports, the fluorescence quenching approach described in this work is simple and rapid with high sensitivity, which has a potential application for detecting various analytes which can be translated into quinone.