Study On Fluorescence Detection System Based On Graphene-Rhodamine Complex

Graphene and graphene-based materials have many unique properties and are widely used in many fields.Reducing graphene oxide（rGO）as a fluorescence quencher can effectively quench the fluorescence of rhodamine B.When a stronger binding agent is added to rGO,Rhodamine B desorbs from the rGO surface,thereby restoring fluorescence.Based on the reversible interaction（adsorption or desorption）between rhodamine B and rGO,a qualitative and quantitative relationship between fluorescence intensity and analyte is obtained.In this thesis,three graphene-rhodamine fluorescence systems were constructed,and the recognition performance of the system was studied by flourescence emission spectroscopy.Studies have shown that the three graphene-rhodamine fluorescence systems can selectively recognizes bisphenol A,ascorbic acid,and tryptophan enantiomers,repectively.The main research contents of the thesis are as follows:1.The rGO-RhB fluorescence system was constructed and its recognition performance for phenolic substances was explored.The results show that the rGO-RhB fluorescence system has a good selective recognition for bisphenol A.The linear range is 100⁸00 nM and the detection limit is 96.54 nM.2.The rGO-RhB-Cr⁶⁺ternary fluorescence system was constructed and its recognition performance for reducing substances and small biomolecules was explored.The results showed that the rGO-RhB fluorescence system had a good selective recognition for ascorbic acid.The linear range is 1¹000 nM and the detection limit is 0.84 nM.3.The rGO-RhB-dibenzoyl-D-tartaric acid ternary fluorescence system was constructed to detect the tryptophan enantiomer,and the difference between the two isomers was explored and compared.For D-tryptophan,the detection range is 600⁸000μM,and the detection limit is 514.69μM.For L-tryptophan,the detection range is 200²000μM,and the detection limit is 132.60μM.This system can significantly distinguish tryptophan isomers.