Construction Of Salt-Induced Hydrophilic Organic Solvents/Deep Eutectic Solvents-Water Phase Separation System And Its Application For Separation And Detection

Salt-induced liquid-liquid separation is a common phenomenon in nature and is widely used in extractive separation of compounds.In recent years,the development of green analytical sample preparation and green separation and analysis technology has become a research hotspot in green analytical chemistry.To progress green chemistry and realize human sustainable development.It is necessary to construct solvent-free,green solvent-salt induced phase separation system,and develop green,sustainable and environmentally friendly extraction technology.Four salt-induced phase separation systems were developed,for recover 2,3-butanediol from fermentation simulation solution and determinate phthalates,glycol and diethylene glycol in food contaminants,based on green analysis chemistry principle of reducing reagent consumption,preferentially using low toxic and renewable regent.The salt-induced phase separation behavior was also studied,providing theoretical basis and data support for its application.The main research contents include:1.Solvent-free and salt-induced phase separation to recover 2,3-butanediol from fermentation simulation solutionThe economy and efficiency were the bottleneck in industrial separation and purification of 2,3-butanediol from fermentation simulation solution.Salt-induced 2,3-butanediol-water phase separation without solvent was constructed to directly recover 2,3-butanediol from fermentation simulation solution.The effects of salt type and concentration,solute concentration,equilibrium time,equilibrium temperature and solution p H on the separation efficiency of 2,3-butanediol were investigated by single factor test.With BDO concentration 15%（wt）,K₅P₃O₁₀ concentration 600 g·kg^-1,equilibrium temperature 55℃,the extraction efficiency,distribution coefficient and selectivity coefficient were 99.5%,2406.1 and 5940.2,respectively.The purification test showed that the dehydration rate of potassium carbonate was the highest,54.4%,and the purity of 2,3-butanediol reached 91.0%.After reused six times,the recovery and extraction efficiency of salt almost did not change.Five salt-2,3-butanediol-water ternary system phase diagrams were drawn,the binodal curves and solid-liquid equilibrium line were fitted with several empirical equations.As a solvent-free,green separation technology,this method has the advantages of high extraction efficiency,simple,economical and easy to scale,providing a new view for separation and refining of 2,3-butanediol from fermentation simulation solution.2.Salt-induced ethanol-water phase separation to determine ethylene glycol and diethylene glycol in liquid samplesEthylene glycol and diethylene glycol are strong hydrophilic organic pollutants in food and food contact materials,it is a challenging work in separation and enrichment of small strong-polar or hydrophilic molecules.This paper constructed salt-induced renewable green ethanol-water phase separation system,and built gas chromatographic method for quantitative analysis of ethylene glycol and diethylene glycol in liquid samples.The single factor test,combined with orthogonal test,was done to optimize process parameters.Under optimal conditions,the linear range was 0.6～60mg·L^-1,correlation coefficient（R²）was>0.9998,limits of detection（LOD）was 0.2 mg·L^-1,the spiked recoveries of real samples as Coke,iced tea,Sprite were 81.2-109.3%,and relative standard deviation（RSD）was0.1～8.6%.Compared with other methods,this method had lower limits of detection.At the same time,it developed high temperature solution-isothermal salting-out method to determine solid-liquid equilibrium line,drew five salt-ethanol-water phase ternary system phase diagrams,discussed the relationship between phase separation and extraction capacity,and fitted binodal curves and solid-liquid equilibrium line with several empirical equations.The proposed method has put a new way for extraction of strong hydrophilic target in aqueous solution,and can be applicable in ethylene glycol and diethylene glycol determination in real samples.3.In-situ salt-induced phase separation to determine phthalate esters（PAEs）in ethanol liquid samplesPAEs are one of highly concerned contaminants in food safety,ethanol in food and food simulants is not conductive in PAEs extraction,even needs evaporation.In this paper,it established in-situ salt-induced ethanol-water phase separation system to separate and enrich 18 phthalate esters（PAEs）in food simulants and food as liquor and beer,and built gas chromatography-mass spectrometry method for quantitative analysis.The effects of salt type and concentration,ethanol concentration,redissolve solvent type,vortex and standing time,and solution p H on separation efficiency were investigated by single test,and extraction conditions were optimized.Under optimal conditions,the 17 phthalates linear range were1～500μg·L^-1(diisononyl phthalate 5～2500μg·L^-1),coefficients of determination（R²）were>0.9979,LODs were 0.014～0.530μg·L^-1,LOQs were 0.047～1.767μg·L^-1,the spiked recoveries were 92.2%～110.2%for real samples as liquor,beer and food simulants,relative standard deviation（RSD）was less than 8.6%.Compared with other methods,the proposed method is simple,no need of additional solvent,high recovery,and has potential application value in food safety control.It opens a new door for separation and enrichment of hydrophobic substances in ethanol liquid samples.4.Salt induced deep eutectic solvents-water phase separation to separate BDO from fermentation simulation solutionNine acidic deep eutectic solvents（ADES）were synthesized and constructed salt induced deep eutectic solvent-water phase separation to separate BDO from fermentation simulation solution.The type and volume of deep eutectic solvents,salt type and concentration,BDO concentration,equilibrium time,equilibrium temperature and solution p H for extraction efficiency were explored with single factor test.Under optimal conditions,when TEAC/n-CA as extractant,the extraction efficiency,selectivity coefficient and distribution coefficient of BDO were 92.3%,281.0 and121.1,respectively.After reusing potassium phosphate five times,the recovery efficiency of salt was over 90%,and extraction rate was more than 92%.The recovery and recycling of extractant were realized by adjusting p H of ADES.The recovery was more than 66%,and the extraction efficiency of BDO was still more than 91%after recycling 5times.The binodal curves for four salt-DES-water ternary system were drawn and fitted with several empirical equations.The results demonstrated that salt-induced ADES-water phase separation was efficient and short in extraction time,environmentally friendly and recyclable.The built method has provided a green and sustainable new thought for BDO extraction from fermentation broth.