Selective Detection of Folic Acid Using a Water-Stable Fluorescent CsPbBr3/Cs4PbBr6 Perovskite Nanocrystal Probe

A water-stable cesium lead bromide (CsPbBr3/Cs4PbBr6) perovskite nanocrystal (PNC) was synthesized and studied as a fluorescence probe for the selective detection of folic acid (FA). The as-prepared PNCs emitted strong green fluorescence at 525 nm, and their structure was systematically characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The interaction between the PNCs and small biological molecules was investigated and the results indicated that the fluorescence of the PNCs could be selectively quenched by FA. The quenching rate has a linear relationship with the concentration of FA in the concentration range from 10 to 800 μM, with a correlation coefficient R2 of 0.9841, and a limit of detection (LOD, 3σ) of 1.69 μM. The mechanism of the interaction between the PNCs and FA was discussed, and the reliability of the method for real sample detection was also verified by the standard addition method. The method proposed here, using a fluorescence PNCs probe, provided a simple alternative strategy for detecting FA that will play an important role in biochemical analysis.