Study On The Build Of A Ratio Fluorescent Probe Based On ZnO QDs And Detection For Tetracycline

Tetracycline(TC)is a commonly used broad-spectrum antibiotic.Due to its broad-spectrum antibacterial properties,good stability and low price,it is widely used in clinical medicine,health care,disease prevention,and animal husbandry.However,large-scale and excessive use caused TC residues,which caused direct and indirect damage to the ecological environment and human health.Therefore,there is an urgent need to establish a detection method for the residues of TC antibiotics to prevent them from causing more far-reaching harm to the human body and the environment.The development of a real-time,visual and convenient trace detection method is the development trend of TC detection in recent years.Fluorescent probe has the advantages of sensitivity,rapidity,multiple methods and convenient operation,so it is widely used in the fields of environmental monitoring,disease diagnosis and food safety analysis.The europium ions(Eu³⁺)-based fluorescent probes for TC detection have attracted widespread attention.Most of the fluorescent probes for detecting TC are based on the principle of single emission fluorescence quenching or enhancement,fluorescence resonance energy transfer,etc.,which causes the problems of sensitivity and specificity in detection.The fluorescent probe prepared in this work is based on the antenna effect of rare earth organic complexes,which effectively enhances the luminescence of rare earth Eu³⁺,and solves the problems of sensitivity and specificity.On the one hand,the?-diketone configuration of TC can form a stable complex with Eu³⁺,which is the premise of using Eu³⁺to detect TC.The complex has the advantages of high luminescence intensity,large Stokes shift and narrow emission band.On the other hand,TC has a strong ability to absorb ultraviolet rays and can be transmitted to Eu³⁺in a non-radiative way,thereby sensitizing Eu³⁺to emit light.These factors determine that Eu³⁺can be used to detect TC.In addition,In addition,in order to reduce the influence of the instrument and the surrounding environment,a reference fluorescence signal is introduced to ensure the accuracy of the test results.Zinc oxide quantum dots(ZnO QDs)has the advantages of excellent optical properties,low toxicity,simple preparation method,low cost,good water solubility,and high biocompatibility.Its advantages make it have great application prospects in bioimaging,drug transportation and food safety testing.Therefore,this paper selects ZnO QDs as the internal reference fluorescence signal.The research results obtained are as follows:1)ZnO QDs modified with 3-aminopropyltriethoxysilane(APTES)was prepared.The structure and morphology characterization shows that the material has a hexagonal wurtzite structure,and its morphology is monodisperse nanospheres(particle size 7nm).Fourier infrared spectroscopy shows that the surface of ZnO QDs has been successfully modified with amino groups(-NH₂),which can meet the needs of subsequent attachment of ligands.Spectral performance tests show that the absorption band of ZnO QDs is located in the ultraviolet region,the best excitation wavelength is365 nm,and the fluorescence emission center is located at 530 nm;the fluorescence quantum yield is 35.8%,and the luminescence performance is stable.2)The ZnO/Eu nanostructure of europium-grafted ZnO quantum dots was prepared.A dual emission ratio fluorescent probe was designed to detect TC using ZnO/Eu nanostructure.In this structure,the fluorescence of ZnO QDs is the reference signal(I₅₃₀),and the fluorescence of Eu³⁺is the sensing signal(I₆₁₆).The ZnO/Eu probe has high sensitivity,I₆₁₆/I₅₃₀ has a linear relationship with the concentration of TC in the aqueous solution in the range of 0-3?M,and the detection limit(LOD)is 4 n M.The probe has a fast response speed and can complete the TC detection within 100 s.In the study on the recovery rate of TC in river water,the recovery rate of TC was between 92.3%and 107.0%,and the relative standard deviation(RSD,n=3)was less than 6.98%.This indicates that the probe shows remarkable high selectivity to TC in a complex actual environment.3)ZnO/Eu fluorescent test paper was prepared by fixing the nano fluorescent probe on the filter paper.The prepared fluorescence test paper can observe the fluorescence change from yellow to red with the naked eye under ultraviolet light,and the detection limit is 0.5?M,which is four orders of magnitude lower than the human harmful threshold(6 ppm).The relative standard deviation of river detection is also less than 6.9%.ZnO/Eu fluorescent test paper can not only realize naked eye detection,but also perform on-site and real-time semi-quantitative analysis through mobile phone applications,realizing fast,sensitive,convenient,and visualized TC detection.