Fluorescence-colorimetric dual detection method for quantitative detection of uric acid in urine based on the...

A dual detection method combining fluorescence and colorimetry used for measuring uric acid (UA) has been developed. Ce⁴⁺ can undergo an oxidation reaction with o-phenylenediamine (OPD) to generate 2,3-diaminophenazine (oxOPD), which exhibits a yellow color and has UV-visible light absorption properties. When UA is introduced into the reaction system, it effectively inhibits the oxidation process between Ce⁴⁺ and OPD, simultaneously resulting in the emergence of a new emission peak at 500 nm in the solution. It is worth noting that both the degree of enhancement in the fluorescence signal intensity at 500 nm and the decrease in the absorbance of oxOPD in the detection system are directly related to the concentration of UA added. Based on this phenomenon, we have successfully designed and implemented a sensitive, simple, and economically applicable fluorescence and colorimetric dual detection method for UA detection. The linear range of the fluorescence detection method is 160-400 μM, with a limit of detection (LOD) of 11.31 μM, while the colorimetric method exhibits a linear range of 5-150 μM and an LOD of 3.55 μM. The fluorescence and colorimetric dual detection method has been successfully applied to the quantitative detection of UA in spiked human urine samples. The recovery rate of fluorescence detection is 95.32-104.08 %, and the relative standard deviation (RSD) is 1.48-5.37 %. The recovery rate of colorimetric detection is 94.40-103.69 %, and the RSD is 1.30-4.11 %. This achievement indicates that it has broad potential application prospects in the field of clinical testing.