Design Of Fluorescent Detection System For Dangerous Harmful Pollutants

Nitrobenzene（NB）and 4-nitrophenol（4-NP）are widely used in medicine,pesticides,fuels,explosives,dyes,textiles and other fields.However,NB and 4-NP are difficult to degrade,and they are highly toxic and carcinogenic.Therefore,how to control these harmful pollutants has attracted increasing attention.At present,the United States,the European Union and China have listed NB and 4-NP as priority pollutants.It can cause a variety of health problems,such as blood,musculoskeletal,skin,respiratory,heart,digestive,liver and kidney damage.Hazardous pollutants such as NB and 4-NP have seriously affected people’s lives and health,so the safety detection of hazardous pollutants is of great significance.Nowadays,most of the methods for detecting this pollutant at home and abroad are expensive and complicated to operate.Due to the advantages of stability and low cost,fluorescent fiber detectors have been widely used in the field of fluorescence detection,and also proposed a new method for the detection of dangerous substances.A new type of sensitive material film was developed,and a fiber-optic fluorescence sensing method for fluorescence detection of hazardous organic pollutants was proposed with a fluorescence fiber sensor.CDs and Eu-MOF were doped and compounded on PVDF film by hydrothermal method,and the mechanism of film detection of pollutants was studied by fluorescence quenching.Ug 3D modeling software was used to create the sensor’s 3D model structure.Matlab and Monte Carlo methods were used to simulate and assess the sensor’s effect on fluorescence coupling efficiency,and the structure of the fluorescence sensor probe was established.Set up an experimental facility to start detecting dangerous compounds and test the performance of the sensors.The main tasks include:（1）We synthesized a lanthanide metal organic framework PVDF film doped with carbon dots by a simple hydrothermal method.1,2,4,5-benzenetetracarboxylic acid（H₄btec）main ligand and 1,10-phenanthroline（1,10-phen）were used as auxiliary ligands.A novel fluorescent thin film sensor（CDs@Eu-MOF/PVDF Film）was designed and successfully prepared by immersing PVDF film in a prepared precursor solution by in-situ growth method and incorporating carbon quantum dots prepared from glucose as raw materials for efficient sensing of p-nitrobenzene and 4-nitrophenol.It not only exhibits excellent solvent resistance,but also exhibits high selectivity and sensitivity.In addition,the synthesized CDs@Eu-MOF/PVDF Film was used as a fluorescent probe.（2）The model structure of the optical fiber fluorescence sensor is designed by ug three-dimensional software,and then the influence of the structural parameters on the coupling parameters is simulated and analyzed by Monte Carlo method.In order to determine the various parameters of the optical fiber sensor,the sensor probe is finally printed by 3D printing with the sensitive film material.According to the findings,increasing the receiving fiber core diameter,decreasing the excitation fiber core diameter,and thickening the sensitive film all boost the fiber’s fluorescence coupling efficiency.Lastly,a core with a diameter of 400μm for the receiving fiber and 0.22 for the numerical aperture are chosen.Fluorescence efficiency peaks at 8.1%at 2100μm,which is the ideal coupling distance.（3）Set up the environment for the detection of dangerous pollutants,using linear array TCD1304 as CCD detector and FPGA as the core chip of the portable spectrum acquisition system to detect the change of fluorescence signal,and finally through the FT245RL transmission to the host computer and display the spectral data.And then compared with the data measured by the Agilent fluorescence spectrometer in the laboratory.Finally,based on the principle of fluorescence quenching,nitrobenzene and4-nitrophenol were detected.The linear ranges were 0-200 mg/L and 0-16 mg/L,respectively.The detection limits were 0.2807 mg/L and 0.0168 mg/L,respectively.