Preparation Of MOFs Coated Stir Bar Adsorption Extraction And Its Application In Trace Organic Pollutants Analysis

Background:Environmental organic pollutants persist in the environment and are difficult to analyse.They exist in trace amounts and are highly toxic and have long-term or potential negative effects on human health and the environment.Nowadays it has become a research hotspot.We are in the Environment and Health in Water Source Area of South-to-North Water Diversion.It is great significance to monitor organic pollutants in the environment.However,there are many types of environmental pollutants,complex matrices,and low levels of target components,which greatly increases the difficulty of analysis.Choosing a reasonable pre-treatment method is the most critical.SBSE is a new miniaturized sample pretreatment technology developed on the basis of solid phase microextraction technology.Not only has the advantages of requiring a small amount of solvent,high efficiency,simple operation,etc,but also can be used with gas chromatography and high performance liquid chromatography,and has been applied to the fields of environmental samples,biological samples and food detection.However,due to the limitations of the coating material,the stirring adsorption extraction technology has a low adsorption and extraction for polar organic compounds.As a new type of adsorbent,metal-organic frameworks（MOFs）are widely used to adsorb and remove organic pollutants.Therefore,a new type MOFs-coated stir bar was developed to increase the range of application of SBSE technology in different organic pollutants.Objective:To synthesize a new metal-organic framework material,prepare a MOFs coated stir bar,and combine the stir bar adsorption extraction technology with high-performance liquid chromatography to detect organic pollution such as estrogens,phthalates,and polycyclic aromatic hydrocarbons in the environment.To meet the extraction requirements of organic pollutants with different properties.Methods:1.MIL-101（Cr）/SiO₂and IRMOF-3 MOFs materials were synthesized by a one-step hydrothermal method.Specific surface,powder X-ray diffraction,and scanning electron microscopy were used to characterize the coating materials.MOFs coated stir bar was prepared by the sol-gel method.2.Combine the PDMS/MIL-101（Cr）/SiO₂coating stir bar with Ultra high performance liquid chromatography to detect phthalate pollutants and estrogen in water and soil,and optimize the main conditions that affect the extraction efficiency of the stir bar Under the optimal conditions,phthalates and estrogen were detected in environmental water and soil.3.Combine the PDMS/IRMOF-3 coated stirring rod with high-performance liquid chromatography to optimize many conditions that affect the adsorption and extraction of 16 polycyclic aromatic hydrocarbons.Under the optimal conditions to detect the content of polycyclic aromatic hydrocarbons in water.Results:1.PDMS/MIL-101（Cr）/SiO₂ coated Stir bar sorptive extraction-ultra-high performance liquid chromatography method was developed for the determination of estrogens and phthalate esters in environmental samples.The extraction conditions were optimized.The extraction time was 30 minutes,the stirring rate was 800 rpm,the p H was 7,the ionic strength was 0%NaCl,and the desorption time was 20 min.Under optimal conditions,water and soil samples were measured,and no estrogen and phthalate were detected.The linear range of this method is 10.00-4375μg/L,the range of R² is 0.9880-0.9998,the detection limit is 0.05-0.095μg/L,and the maximum enrichment factor can reach98.8 times.The method was successfully applied to the detection of phthalates and estrogens in environmental water and soil.2.PDMS/IRMOF-3 coated Stir bar sorptive extraction was established in combination with high-performance liquid phase to detect polycyclic aromatic hydrocarbons in water.The optimal extraction time was 35 min,the extraction rate was 900 rpm,the temperature was 25℃,and the adsorption agent:acetonitrile and the adsorption time were 10 min.Under the optimal extraction conditions,two water samples were measured.The linear range is10-400 ng/L,the R² range is 0.9908-0.9991.the detection limit is 0.3-22 ng/L.This method is successfully applied to the detection of polycyclic aromatic hydrocarbons in environmental water.Conclusion:The MOFs-coated SBSE was successfully applied to the adsorption and extraction of different polar compounds,the analytical method of organic pollutants in environmental water and soil was successfully established,The results were satisfied.