Carbon Quantum Dots-Based Fluorescence Spectrophotometric Assay of Folic Acid

In NaH2PO4. Na2HPO4 buffer medium (pH 7.3), the electrostatic interaction of folic acid with carbon quantum dots results in the fluorescence quenching of carbon quantum dots characterized at 384 nm. Experiments showed that the quenched fluorescence intensity was in proportional to the concentration of folic acid content over the range of 0.025-2.0 mu mol/ L with a correlation coefficient of 0.9947. Therefore, a sensitive fluorescence spectrophotometric method for the determination of folic acid was developed. The limit of detection (LOD) was 2.5 nmol/ L. In this work, the fluorescence spectra, UV-Vis spectra and fluorescence lifetime were characterized. The reaction mechanism and the optimum of reaction condition were also investigated. The method has been applied for the determination of folic acid in simulated serum with the recovery from 97.3% to 101.6% and the RSD lower than 4.9%.