Fluorescence enhancement detection of uric acid based on water-soluble 3-mercaptopropionic acid-capped core/shell ZnS:Cu/ZnS

Abstract

3-Mercaptopropionic acid (MPA)-capped ZnS:Cu/ZnS core/shell quantum dots (QDs) have been synthesized via a facile aqueous coprecipitation method and characterized by fluorescence, UV-Vis absorption, infrared spectroscopy and transmission electron microscopy. The fluorescence of ZnS:Cu/ZnS could be increased in the presence of uric acid (UA). The affecting factors for the fluorescence of ZnS:Cu/ZnS were examined including pH, temperature and reacting time. Under the optimized conditions, the fluorescence intensity of the ZnS:Cu/ZnS QDs against the UA concentration showed a linear response in the range of 0.66 μM to 3.3 μM with the correlation coefficient (R²) 0.9973 and the limit of detection 0.044 μM. Most relevant molecules and physiological ions had no effect on the detection of UA. The feasibility of the developed method was further demonstrated by determining the concentration of uric acid in human urine samples and the recoveries were 95% ∼ 103%. Our work provides a sensitive, selective and convenient fluorescence method to determine UA in real samples.