Effervescent Tablet-Assisted Dispersion Liquid-Liquid Microextraction Based On Acidic Ionic Liquid And In Situ Metathesis Reaction For The Determination Of Bisphenol Pollutants

Bisphenolic pollutants（BPs）are typical endocrine disruptors that do harm to aquatic organisms and human health due to their chronic exposure.For example,BPs can induce chromosomes abnormality and damage the reproductive system.Ionic liquids（ILs）are well known as“green solvent”and widely employed in the fields of extraction and separation due to their several advantages,such as low viscosity,high density,structural designability,environmental friendliness,and hydrophobicity or hydrophilicity.Acidic task-specific ionic liquids have specific functions owing to the presence of acidic groups on their cationic or anionic groups,and are widely used as reaction media and catalysts for various reactions.Traditional dispersive liquid-liquid micrextraction（DLLMEs）often requires the dispersive solvents at m L level,such as methanol,acetone or acetonitrile,to ensure complete contact between extractant and sample solution.In addition,the dispersive process usually requires additional physical energy to assist,which results in energy consumption and complicated extraction process.Therefore,this study integrated acidic ionic liquids（AILs）,effervescent dispersive liquid-liquid microextraction and fatty acids,and utilized their advantages to achieve the purpose of simple,rapid,sensitive,and efficient monitoring of trace-level BPs.The main research contents are summarized as follows:（1）In the first part,we developed an effervescent-assisted dispersive liquid-liquid microextraction method for concentration/extraction of bisphenols（BPs）in milk and milk tea samples.This microextraction method is based on the utilization and in-situ metathesis reaction of acidic ionic liquids,abbreviated as AI-EDLM.Compared to traditional imidazole-based ILs,AILs can not only act as extractants but also as acid sources in effervescent reactions.Under such circumstances,not only the use of organic solvent is eliminated,but also the vigorous CO₂bubbules produced by an effervescent reaction achieve the effect of rapid dispersion without additional dispersive steps,thus simplifying the experimental procedures.By using the“one-factor-at-a-time”optimizatin method,the main parameters were optimized as follows:400 mg of[BMIM][HSO₄]as extractant,100mg of Na₂CO₃as alkaline source,400 mg of Li[NTf]₂as ion-exchange reagent,4%Na Cl,5-min centrifugation,and 1.5 m L of ether as elution solvent.Under optimized conditions,the detection limits of BPs in five milk samples ranged from 0.12 to 0.32μg·L^-1,and the extraction recoveries for BPA,BPB,and BPAF ranged from 85.7%to 106.2%.Therefore,AILs（[BMIM][HSO₄]）play a dual role in the AI-EDLM procedures,namely extraction agent and p H modifier.Overall,the method is simple,rapid,and environmentally friendly,with low detection limits and high recoveries for BPs,and has good application prospects in sample preparation and BPs detection in milk and milk tea samples.（2）In the second part,we developed an effervescent-assisted microextraction method based on AILs and switchable hydrophilic-hydrophobic fatty acids（SHFAs）for the detection of BPs in edible oils.This microextraction method is based on the utilization and in-situ metathesis reaction of AILs,hereafter referred to as EM-ASH.In the EM-ASH procedures,SHFAs play a triple role:（1）as a dispersant during microextraction,（2）as an acid source during the effervescent reaction,and（3）realization of transition from hydrophilicity to hydrophobicity after extraction.Compared to traditional imidazole-based ILs,AILs can not only act as extractants,but also as acid sources for effervescent reactions.Therefore,the use of organic solvents is not required,and the CO₂generated by an effervescent reaction realizes the rapid dispersion of extractant and no requirement for additional dispersive steps,thereby making the experimental processes more simple and convenient.By virtue of the single-factor optimization and screening,the main variables were summarized as follows:300 mg of[BMIM][HSO₄]as extractant,500μL of caprylic acid,0.3 g of Na₂CO₃as alkaline source,300 mg of Li[NTf]₂as ion-exchange reagent,1.5m L of H₂SO₄as acid source.Under the best opertional conditions,the detection limits of six edible oil samples spanned the range of 0.11-0.35μg·L^-1,and the extraction recoveries for BPA,BPB,BPAF,and BPAP varied between 88.3%and 106.7%.Overall,the newly developed method is simple,rapid,and environmentally friendly,with low detection limits and high recoveries for BPs,and thus has a great potential in sample pretreatment and trace-level BPs detection in edible oil samples.