Extraction Of Drug Residues From Animal-derived Foods And Environmental Water By Functionalized Covalent Organic Frameworks

Veterinary drugs are often used in the fields of animal husbandry and aquaculture to control general and infectious animal diseases,as well as to regulate animal physiological functions,and promote the quality and yield of animal-derived foods.With the long-term use of veterinary drugs in large quantities,the residual drugs that have not been metabolized by animals will enter the environment through their excrement,and aquaculture drug application will directly affect water quality.Drug residues in animals,contaminated soil,water and other crops are transferred into human bodies through the food chain,endangering life and health.Therefore,establishing an effective method for the analysis and detection of veterinary drug residues in food and the environment is of great scientific research and practical significance.Covalent organic frameworks（COFs）have many advantages for sample pretreatment,including large specific surface area,easy pore size adjustment,easy surface functionalization,good thermal stability and chemical stability.Based on the characteristics above,this paper combined COFs with magnetic nanoparticles and metal organic framework materials（MOFs）to prepare new functionalized COFs composite materials by simple methods.Relying on solid phase extraction and magnetic solid phase extraction technology,the prepared materials can play a reliable role in the domain of food and environmental samples pretreatment,and analytical detection methods with ideal efficiency and outstanding effect have been established.This paper has studied the following contents specifically:1.Magnetic covalent organic framework composite materials Tp BD@Fe₃O₄was prepared by room temperature synthesis for magnetic solid phase extraction of sulfonamides（SAs）residues in milk and meat samples,and the extracted products were detected by high performance liquid chromatography.Due to theπ-πand electrostatic attraction between the benzene ring structure of Tp BD and SA molecules,Tp BD@Fe₃O₄ exhibited higher extraction efficiency.The samples,reagents and time conditions related to the extraction and elution processes were investigated and the methodological parameters had been evaluated.The results showed that the method had a wide linear range（50～5×10⁴ ng/m L）and exhibited low limits of detection（3.39～5.77 ng/m L）.The practicability of this method was further evaluated by analyzing milk and pork samples,of which the recoveries of the targets ranged from 71.6%to 110.8%in milk and 71.9%to 109.7%in pork.The research results have demonstrated that the Tp BD@Fe₃O₄ can be successfully used as a pretreatment material for complex matrix samples,with the mild preparation conditions as well as simple and rapid extraction operation.The established magnetic solid phase extraction-high performance liquid chromatography method excelled at practical potential for analyzing pharmaceutical residues in animal-derived foods.2.Metal organic frameworks（MOFs）can obtain decent adsorption properties due to their coordination effects.With their metal center and easily modified surfaces,they can be used as support materials to form a novel class of composites（COFs@MOFs）by hybridizing with covalent organic frameworks.COFs@MOFs can be used for enrichment of trace target substances with enhanced adsorption capacity.In this chapter,the COFs@MOFs composite Tp BD@Ui O-66 was prepared by growing the covalent organic framework Tp BD in-situ on the surface of the metal organic framework Ui O-66.The prepared Tp BD@Ui O-66 was used as the solid phase extraction adsorbent to enrich fluoroquinolones（FQs）residues in environmental water samples,and the extraction products were detected by high performance liquid chromatography.Tp BD@Ui O-66 mainly adsorbs FQs throughπ-πinteractions,hydrogen bonds,coordination and electrostatic interactions.The solid-phase extraction conditions such as the extractant dosage,eluent type and dosage,and the p H of the sample solution were optimized experimentally.Meanwhile,the methodological parameters have been investigated.The results showed that the method had an ideal linear range（0.1～50μg/m L）and low limits of detection(0.24×10^-3～0.87×10^-3μg/m L).The recoveries measured by the standard addition method for the actual river water samples ranged from 71.2%to106.8%.The research showed that the preparation process of Tp BD@Ui O-66composites didn’t require harsh reaction conditions,the extraction process was simple and time-saving,and the Tp BD@Ui O-66 exhibited more comprehensive advantages in the pretreatment of environmental samples.The established solid phase extraction-high performance liquid chromatography method has the ability and practical value to analyze pharmaceutical residues in environmental water samples.