Determination of catecholamine in human serum by a fluorescent quenching method based on a water-soluble fluorescent conjugated polymer–enzyme hybrid system

In this paper, a sensitive water-soluble fluorescent conjugated polymer biosensor for catecholamine (dopamine DA, adrenaline AD and norepinephrine NE) was developed. In the presence of horse radish peroxidase (HRP) and H2O2, catecholamine could be oxidized and the oxidation product of catecholamine could quench the photoluminescence (PL) intensity of poly(2,5-bis(3-sulfonatopropoxy)-1,4-phenylethynylenealt-1,4-poly(phenylene ethynylene)) (PPESO3). The quenching PL intensity of PPESO3 (I0/I) was proportional to the concentration of DA, AD and NE in the concentration ranges of 5.0 × 10−7 to 1.4 × 10−4, 5.0 × 10−6 to 5.0 × 10−4, and 5.0 × 10−6 to 5.0 × 10−4 mol L−1, respectively. The detection limit for DA, AD and NE was 1.4 × 10−7 mol L−1, 1.0 × 10−6 and 1.0 × 10−6 mol L−1, respectively. The PPESO3–enzyme hybrid system based on the fluorescence quenching method was successfully applied for the determination of catecholamine in human serum samples with good accuracy and satisfactory recovery. The results were in good agreement with those provided by the HPLC-MS method.