Research On The Detection Method Of Antibiotic Pollutants Based On Graphene Quantum Dot Molecularly Imprinted Polymer

Antibiotics,which have good effects on antimicrobial and bacteriostatic,are widely used in the prevention and treatment of human and animal diseases.Studies have shown that antibiotics are non-degradable substances.High concentration of antibiotics will have toxic effects on the ecological environment and will cause drug resistance in human body.Therefore,the development of a sensitive and selective method for detecting antibiotic is of important academic value and practical significance.Graphene quantum dots(GQDs)are novel carbon nanomaterials with high fluorescence properties and excellent water solubility.It was found that the fluorescence of GQDs could be quenched by antibiotics,which can be used to detect antibiotic concentration.However,the selectvitity of GQDs is not very good for the determination of antibiotics.Molecularly imprinted polymers(MIPs)are polymers with specific recognition properties for template molecules.With the advantages of low cost,simple preparation and stable chemical properties,MIPs have great potential in the detection of environmental pollutants.In this paper,by combining the sensitive fluorescence properties of GQDs with the specific recognition characteristics of MIPs,three kinds of graphene quantum dot molecularly imprinted polymers were prepared and used to detect tetracycline,chloramphenicol and doxycycline,respectively.The research contents are as follows:(1)Determiantion of tetracycline based on polyindole modified graphene quantum dot molecularly imprinted polymers(PIn/GQDs@MIPs).The GQDs were derived from citric acid,and then the PIn/GQDs@MIPs were successfully prepared by the polyindole(PIn)as substrate and tetracycline(TC)as template molecule.It was achieved that detecting TC selectively and sensitivitly because that the fluorescence of PIn/GQDs@MIPs could be quenched by TC.The results indicated that the detection range of TC was 0.1-1.0 μM and 1.0-50.0μM,and the detection limit was 33 nM.When PIn/GQDs@MIPs were used to detect TC in actual water samples,the recovery was 105%-110%,and the relative standard deviation was 4.4%-6.8%.(2)Detection of chloramphenicol based on nitrogen-doped graphene quantum dot surface molecularly imprinted polymers(N-GQDs/SiO2/MIPs).Nitrogen-doped graphene quantum dots(N-GQDs)were synthesized by one-step pyrolysis using citric acid as carbon source and aminobutyric alcohol as nitrogen source.Spherical silica dioxide was coated on the periphery of N-GQDs.Nitrogen-doped graphene quantum dot surface molecularly imprinted polymers(N-GQDs/SiO2/MIPs)were synthetized triumphantly with chloromycin(CAP)as template molecule.The fluorescence intensity of N-GQDs/SiO2/MIP,was significantly increased due to the doping of nitrogen atoms.It was achieved that detecting CAP selectively and sensitivitly because that the fluorescence of N-GQDs/SiO2/MIPs could be quenched by CAP.The result indicated that the detection range of CAP was 0.15-4.64 μM,and the detection limit was 53 nM.When N-GQDs/SiO2/MIPs were used to detect CAP in actual water samples,the recovery rate was 93%-111%,and the relative standard deviation was 0.65%-5.07%.(3)Detection of doxycycline based on nitrogen and sulfur co-doped graphene quantum dot mesoporous molecularly imprinted polymers(N,S-GQDs/SiO2@MIPs).Nitrogen and sulfur co-doped graphene quantum dots(N,S-GQDs)were synthesized by one-step pyrolysis using citric acid as carbon source,thiourea as nitrogen source and sulfur source.Based on doxycycline(DOX)as template molecule and Cetyltrimethylammonium Bromide(CTAB)as pore-forming agent,the mesoporous nitrogen and sulfur doped graphene quantum dots molecularly imprinted polymers(N,S-GQDs/SiO2@MIPs)were successfully prepared.It was achieved that detecting DOX selectively and sensitivitly because that the fluorescence of N,S-GQDs/SiO2@MIPs could be quenched by DOX.The result indicated that the detection range of DOX was 0.16 μM-23.81 μM,and the detection limit was 50 nM.When N,S-GQDs@MIPs were used to detect DOX in actual water samples,the recovery was 95%-109%and the relative standard deviation was 1.4%-5.7%.