Detection Of Organophosphorus Pesticides Based On Molybdenum Disulfide And Molecular Imprinting Materials

In agricultural production,organophosphorus pesticides have the effect of controlling crop diseases and insect pests and improving the yield of agricultural products.However,the irregular use of organophosphorus pesticides leads to serious residues in the environment and finally enters the human body through the food chain,causing serious harm to human health.Therefore,it is very important to develop a simple,efficient,and highly sensitive technique for organophosphorus pesticide residue detection.At present,the preparation of materials with high adsorption recognition performance has become a research hotspot for researchers in the development of organophosphorus pesticide detection technology.Molybdenum disulfide is a new material,which has the advantages of high specific surface area,rapid mass transfer rate and good stability;molecular imprinting materials have the advantages of specific recognition,many affinity sites and high stability.However,the synthesis step of molybdenum disulfide(complex)is cumbersome and does not have specific adsorption capacity;molecular imprinted materials have disadvantages such as slow recognition rate and low adsorption capacity.In this study,a composite with high adsorption capacity and specific recognition function was synthesized by the functionalization combination of materials to solve the shortcomings of single materials themselves.The flower-like molybdenum disulfide,magnetic flower-like molybdenum disulfide and magnetic molybdenum disulfide/molecular imprinting hybrid materials were prepared experimentally,which simplified the synthesis conditions and improved the material properties.It is introduced as a new adsorbent into the enrichment detection of organophosphorus pesticides,which provides an important reference for the development of new organophosphorus pesticide residue detection technology.The main results of this paper are as follows:(1)The flower-like molybdenum disulfide material was prepared by simple solvothermal method and used as a solid phase extraction adsorbent.The extraction conditions such as loading volume,eluent type,and elution reagent were investigated,and a SPE-HPLC-MS/MS method for the enrichment and detection of organophosphorus pesticides in environmental water samples was established.When the loading volume was 30 m L,the p H was 7,the eluent was 5 m L H₂O,the elution solvent was 3 m L,and acetone/n-hexane(1:1 v/v),the linear relationship of the eight organophosphorus pesticides was good in the range of 0.5?200 ng/m L,and R²was greater than 0.9941.In this study,molybdenum disulfide was introduced into the sample pretreatment process as a new adsorbent,which has important reference value for the enrichment of other trace pollutants.(2)Magnetic flower-like molybdenum disulfide was prepared by in situ polymerization,and its application in enrichment and detection of organophosphorus pesticides was explored.Positively charged Fe³⁺is attached to the molybdenum disulfide surface by coordination,and under certain conditions,Fe²⁺and OH^-are added to react to generate a magnetic composite.The synthesized magnetic composite was analyzed and evaluated by a series of characterizations,and the prepared composite has the advantages of large specific surface area(243.1 m²/g),strong magnetism,and high stability.The adsorption conditions of organophosphorus pesticides were investigated by magnetic solid phase extraction pretreatment technique.The optimal magnetic solid phase extraction conditions were determined.A MSPE-HPLC-MS/MS method for rapid enrichment and detection of organophosphorus pesticides in environmental water samples was established.The recovery of organophosphorus pesticides(86.1%?102.3%)was good at three different addition levels(10,20,50 ng/m L),and the relative standard deviation was 1.4%?6.8%.The established detection method has the advantages of high sensitivity and good repeatability.(3)Magnetic molybdenum disulfide/molecular imprinting hybrid materials using fenthion as template molecule were prepared by surface imprinting technique.The adsorption properties of the hybrid materials were analyzed and evaluated by dynamic and static adsorption experiments and the Scatchard equation,and a MSPE-HPLC-MS/MS method for the enrichment and detection of five organophosphorus pesticides in agricultural products(cucumber,zucchini,apple,and peach)was established based on this material.The experimental results showed that at three addition levels(20,50,100 ng/m L),the spike recoveries of the five organophosphorus pesticides were good(83.5%?105.2%).The MSPE-HPLC-MS/MS method established in the experiment has the advantages of short time,high sensitivity and good repeatability in the enrichment and detection of organophosphorus pesticides in agricultural products.This study provides a selective identification adsorption material for enrichment detection of organophosphorus pesticides in agricultural products,and has important reference value for enrichment detection of other trace pollutants in agricultural products.