| Environmental water is one of the leading media for organic pollutants to migrate to human.It is of great significance to detect concentrations of contaminants contained in environmental water.For some complex environmental water samples,the types of organic pollutants in them are complex,and the concentrations of different substances vary greatly.The target must be enriched and purified by sample pretreatment and distinguished by an analytical instrument.However,typical liquid-phase microextraction methods still have some problems,such as halogenated organic solvents as extractant and dispersive,using microsyringe to collect extraction agents.These problems lead to a low green degree,lacking precision and difficulty in automation.To solve these problems,several improvement measures were proposed and verified in this paper to improve the liquid phase microextraction method’s treatment efficiency and greenness.The main includes content includes:(1)In the introduction,the devices and solvents of liquid-phase microextraction are reviewed.The development of single droplet microextraction,hollow fibre tube microextraction,dispersive liquid-liquid microextraction and their respective advantages,and applying different green solvents in liquid-phase microextraction.The classification,properties and application of deep eutectic solvents(DES)and the technology of molecular simulation design of DES are introduced.Then,this paper’s research significance and content are put forward in combination with the current development direction.(2)Determination of benzene series in environmental water by high throughput liquid-liquid microextraction device.A liquid-phase microextraction device,which can be used in the automatic gas chromatographic sampler and perform 16 extraction groups simultaneously,was proposed.The device integrates the extractant collection and injection steps by a unique device,avoiding contamination and deviation caused by syringes for transfer.The detection of benzene series evaluated the validation of the method in water samples.Then,the single factor method was used to optimize the extractant selection,and the response surface method was used to optimize the volume of extractant,extraction time and the salt concentration of the water sample.The results show that this method is simple,efficient and high-throughput with enrichment factors(EF)between 254-1094 and relative standard deviations(RSD%)between 2.2 and 6.2.(3)Determination of polycyclic aromatic hydrocarbons in environmental water samples by DES liquid-liquid microextraction.Lauryl alcohol as hydrogen bond donors,thymol and menthol as hydrogen bond donors,several hydrophobic green DES with low viscosity were synthesized.The components in the solvent are only bonded by hydrogen bonds,which IR and ~1H NMR verify.The Blends model simulated the compatibility of DES with pyrene,and experiments verified the simulation results.A set of pretreatment methods was established by applying DES in dispersive liquid-liquid microextraction to detect the content of polycyclic aromatic hydrocarbons in water samples.The extractant type,proportion,volume,extraction time,p H and salt concentration of water samples were optimized.The PAHs in environmental water samples were determined.The results showed that the enrichment factors of this method were between 243 and 274,the relative standard deviation was between 3.8 and 6.8%,and the total extraction time was less than 10min.Compared with the conventional method of deep eutectic solvent dispersive liquid-liquid microextraction,the extractant dispersion procedure is simplified.(4)Thermo-sensitive DES-DLLME for the detection of pesticides in environmental water samples.A temperature-sensitive DES was synthesized from oleic acid and lidocaine and was applied to the dispersive liquid-liquid microextraction.The components in the solvent are only bonded by hydrogen bonds,which IR and ~1H NMR verify.A simplified dispersive liquid-liquid microextraction method was developed.The organophosphorus pesticides and pyrethroids in water samples were extracted and determined by HPLC.The extractant volume,salt concentration,water bath temperature and water bath time were optimized,and the method was applied to the detection of pesticides in environmental water samples.The results showed that this method’s detection limit was between 0.16-0.81μg L-1,the relative standard deviation was between 0.8-9.1%,and the extraction time was only 5 minutes.The solvent collection step of dispersive liquid-liquid microextraction is simplified,and the rapid,green and efficient extraction is realized. |
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