Fluorescent And Visual Detection Of Fluoride Ion Using Photoluminescent Graphene Oxide Paper Sensor

The examine methods for fluoride anions have attracted growing interest in past decades. The instant and on-site detection of trace aqueous fluoride ion is still a challenge for environmental monitoring and protection.This work demonstrates a new analytical method and its utility of paper sensor for visual detection of fluoride ion on the basis of the fluorescence resonance energy transfer (FRET) between photoluminescent graphene oxide (GO) and silver nanoparticles (AgNPs) through the formation of cyclic esters between phenylborinic acid and diol. The fluorescence of GO was quenched by the AgNPs linked on the surfaces of GO. In the presence of F-, the boronate ester is converted to trifluoro borate, which causes the breakage of the linkage and disassembles photoluminescent GO from AgNPs, resulting in the fluorescence recovery of the quenched photoluminescent GO. Experimental results indicate that the increase in fluorescence intensity is proportional to the concentration of F- in the range of 0.05-0.55 nmol/L, and the detection limit was obtained as low as 9.07 pmol/L.Taking advantage of this phenomenon, a paper-based sensor for the visual detection of aqueous F- has been successfully developed. The paper sensor showed high sensitivity for F- visual detection, and the portable sensors are rapid, simple, efficient and inexpensive. The detection limit of this facile method could reach as low as 0.1 μmol/L with the naked eye.