Carbon quantum dots with green fluorescence as a probe for detecting uric acid

Green-fluorescent nitrogen-doped carbon quantum dots (g-CQDs) were synthesized via a simple and convenient one-step hydrothermal method using Passiflora edulis sims shell as a carbon source and m-phenylenediamine as a nitrogen source and applied to the detection of uric acid. Unlike most reported blue fluorescent probes, the obtained g-CQDs showed bright-green fluorescence under ultraviolet light with a high quantum yield of 37.6%. Moreover, the g-CQDs exhibit outstanding photostability and high sensitivity, an excellent linearity ranging from 1 to 17 µM, and a great limit of detection of 0.94 µM, which renders them suitable for the determination of uric acid in human urine with remarkable selectivity.