Study On Eco-environmental Behavior Of Imidacloprid,Fe²⁺ And Hydrazine Based On Fluorescence Technology

Environmental pollution has become one of the most serious problems affecting human health with the rapid development of economy.The uncovering of the distribution,transport and transformation mechanisms of pollutants in the ecological environment is an effective way to control environmental pollution from the source.It is of great significance to understand the transport and transformation mechanism of pollutants in the ecological environment.In the previous decades,the distribution and transport of pollutants in the ecological environment has been visualized mainly through isotope labeling techniques.However,their drawbacks such as high cost,radioactive nature,and complexity of operation and handling have limited their application.Fluorescence techniques are gradually replacing isotope labeling techniques with the advantages of simple operation,adjustable fluorescence,fast detection,good reproducibility,and no radiation for the study of environmental behavior of pollutants.Based on this,this paper adopts fluorescence technique as the main research tool,and uses imidacloprid,Fe²⁺and hydrazine as research materials,combined with fluorescence microscopy to visualize uptake,distribution and transformation mechanisms of pollutants in the ecological environment or plants,so as to provide a theoretical basis for reducing the harm of environmental pollutants to the ecological environment.The main results are as follows:1.Imidacloprid silica nanocarriers(FL-MSNs@Im)with stable fluorescence were constructed by modifying mesoporous nanosilica with carbon quantum dots.The design of double hollow shell increases the load capacity(?30%)and extends the release rate of FL-MSNs.FL-MSNs@Im can control the release of imidacloprid by adjusting the p H value.The use of FL-MSNs@Im can improve the utilization of imidacloprid and reduce ecological environmental pollution.2.The distribution,translocation and metabolic behavior of imidacloprid in pakchoi tissues were studied by combination methods of fluorescence microscopy and UPLC-MS/MS.FL-MSNs@Im was transported from the ducts to the stem and leaf parts mainly through transpiration under root application.FL-MSNs@Im were transported downward from the sieve tube of the bast mainly with the nutrients produced by photosynthesis after foliar application.FL-MSNs@Im can prolong the duration of imidacloprid,decrease the amount of application,and reduce ecological pollution.3.The results of distribution,transport and metabolism of imidacloprid in tomato tissues showed that the mobility of FL-MSNs@Im was higher under light conditions than under weak light conditions.FL-MSNs@Im was transported from the duct to the stem and leaf parts by transpiration under root application and could not enter the tomato fruit.FL-MSN@Im was transported from top to bottom through dual transport pipelines of screen tubes and ducts after foliar application.Compared to 70% imidacloprid aqueous dispersion granules,FL-MSN@Im can produce less metabolites on tomatoes,which provides a good idea for the safe use of pesticides with high toxic metabolites.4.A method of monitoring the environmental behavior of Fe²⁺based on a fluorescent probe technique was developed(DDED).The ultra-large Stokes shift (>275 nm)of DDED enhances its penetration into cells as well as tissues and reduces background fluorescence interference.This technique allows visual monitoring of Fe²⁺distribution in cells and zebrafish in real time.DDED enables the study of the environmental behavior of contaminants not only qualitatively but also quantitatively.DDED provides insight into the distribution and transport of pollutants in the ecological environment at the cellular level.5.A novel hydrazine near-infrared fluorescent probe(DCDB)was synthesized.DCDB exhibited advantages of large Stokes shift(160 nm),low cytotoxicity,high selectivity and high sensitivity.HNMR,DFT and HRMS confirmed the reaction mechanism of DCDB with N₂H₄.In addition,the studies of potential application showed that DCDB can effectively monitor the distribution of N₂H₄ in environmental water samples,cells and zebrafish in real time.