Enzyme-coupled fluorescence sensor for sensitive determination of uric acid and uricase inhibitor.

In this work, an enzyme-coupled fluorescence sensor was developed successfully for the sensitive detection of uric acid (UA) and uricase inhibitor based on graphene quantum dots (GQDs). UA is first oxidized by uricase and produced hydrogen peroxide (H2 O2 ), which could oxidize phenol to benzoquinone in the presence of horseradish peroxidase (HRP) as the catalysis. Benzoquinone is an efficient quencher and can cause the fluorescence quenching of GQDs. It is found that the quenching degree was proportional to UA concentration and was liner to UA concentration in the ranges of 0.2-14 μmol/L. The detection limit was 0.06 μmol/L for UA. In addition, the proposed sensor was further utilized to the UA detection in human serum samples with satisfactory reproducibility and accuracy. The proposed strategy provides may be widely utilized to the sensing of H2 O2 or H2 O2 generating process in related biological environment.