Performance Research Of Hydrophobic Deep Eutectic Solvents-Based Vortex-Assisted Liquid-Liquid Microextraction

High-efficiency,economical and environmental-friendly sample preparation method has always been one of the most important directions in the field of analytical chemistry.Traditional liquid-liquid extraction method is always time-comsuing,environmental-polluting,and requires tedious operation,large amount of organic solvents.However,liquid-phase microextraction method,as an environmental-friendly sample preparation technology,overcomes the above shortcomings,and has higher sensitivity,better enrichment effect,so it is suitable for the determination of trace or ultra-trace substances in samples.Deep eutectic solvent which can be prepared simply,is low cost,no toxic effect,green,biodegradable,and has atomic util ization rate of 100%in the synthesis process.It conforms to the concept of green chemistry and is considered to be a good alternative to traditional volatile organic solvents and ionic liquids.Based on these,several hydrophobic deep eutectic solvents were prepared and used as extractants for vortex-assisted liquid-liquid microextraction.Combined with high performance liquid chromatography,a deep eutectic solvent-vortex-assisted liquid-liquid microextraction-high performance liquid chromatography detection method was established and used in the analysis of contaminants in environmental and food samples,broadening the application of deep eutectic solvent in sample preparation.The main research content is as follows:1.Using trioctylmethylammonium chloride as the hydrogen bond acceptor and oleic acid as the hydrogen bond donor,four different molar ratios of hydrophobic deep eutectic solvents were synthesized and characterized.The deep eutectic solvents were used as the extractants of the vortex-assisted liquid-liquid microextraction method and combined with high performance liquid chromatography,a deep eutectic solvent-vortex-assisted liquid-liquid microextraction-high performance liquid chromatography assay was used for detection and analysis of Sudan I dye in environmental and food samples.Factors affecting the extraction effect such as the type and amount of extractant,the concentration of NaCl,the vortex time,and the pH conditions were optimized.Under the optimized conditions,this method has good selectivity for Sudan I,the linear range was 1~200μg/L,with a correlation coefficient R~2 of 0.9992.The limit of detection was 0.2μg/L,and the limit of quantitation was 1μg/L.The intra-day relative standard deviation was 1.5%and the inter-day relative standard deviation was 3.0%.This method was successfully applied to the detection of Sudan I dyes in river water,tap water,duck blood,and chili powder,and the relative recoveries were 81~116.8%.Comparing with other extraction methods,this method has the advantages of easy to operate,rapid,green and environmental-friendly,and it also has good linearity,relatively low limit of detection and relative standard deviation.2.Using trioctylmethylammonium chloride as the hydrogen bond acceptor and oleic acid, hydroquinone,p-hydroxybiphenyl,and 4-cyanophenol as hydrogen bond donors,several different kinds and molar ratios of hydrophobic deep eutectic solvents were synthesized and characterized.The deep eutectic solvents were used as the extractants of vortex-assisted liquid-liquid microextraction method and combined with high performance liquid chromatography,a deep eutectic solvent-vortex-assisted liquid-liquid microextraction-high performance liquid chromatography detection method was established for the detection and analysis of formaldehyde in environmental and food samples.This method is based on the derivatization reaction of formaldehyde and 2,4-dinitrophenylhydrazine under acidic conditions,and the formaldehyde is quantified indirectly by measuring the obtained phenylhydrazone.Factors affecting the extraction efficiency such as the derivatization reaction conditions including reaction pH conditions,temperature,time and extraction conditions including the type and amount of extractant,the influence of NaCl,vortex time,and centrifugation time were optimized.Under the optimized conditions,the method has a linear range of 1~200μg/L,with a correlation coefficient R~2 of 0.9994,limit of detection of 0.2μg/L,limit of quantitation of 1μg/L,intra-day relative standard deviation of 1.1%,and inter-day relative standard deviation of 4.6%.It has been successfully applied to the analysis and determination of formaldehyde in air and animal blood products,and the relative recoveries were 83.1~104.4%.Comparing with other extraction methods,this method has the advantages of simple operation,rapid analysis,and environmental protection.The linear relationship is good and the relative standard deviation is relatively low.