Determination Of Functional Active Substances In Shanxi Vinegar Based On Hydrophobic DES-VALLME-HPLC

Shanxi vinegar contains flavonoids,polyphenols,organic acids,amino acids and other functional ingredients,because of its unique brewing technology.The matrix interference is serious when analyzing the active substances with low content in Shanxi mature vinegar.It is very important to develop simple and effective sample pretreatment and detection methods.Liquid-liquid microextraction is a kind of environmentally friendly sample pretreatment technology with high enrichment effect,which is suitable for the determination of trace or ultra-trace substances in samples.Deep eutectic solvent has the advantages of simple preparation process,low cost,non-toxic,green and biodegradable.A method of hydrophobic eutectic solvent-vortex assisted liquid-liquid microextraction-high performance liquid chromatography was developed for the determination of functional active components in Shanxi mature vinegar.The main research contents are as follows:1.Four kinds of hydrophobic eutectic solvents were synthesized by using tetraethylammonium chloride and tetrabutylammonium chloride as hydrogen bond acceptors and n-octanoic acid and n-decanoic acid as hydrogen bond donors.A novel method of hydrophobic deep eutectic solvent vortex assisted liquid-liquid microextraction high performance liquid chromatography was developed for the determination of phenolic acids in Shanxi vinegar.The factors affecting the extraction effect,such as the type and amount of DES,the molar ratio of HBA to HBD,vortex time,centrifugation time,and the addition of Na Cl,were optimized.Under optimized conditions,the linear ranges of this method for phenolic acids were 0.5?50?g/m L,the correlation coefficients R~2were 0.98941?0.99861,the detection limits were 0.08?0.17?g/m L,the quantification limits were 0.24?0.49?g/m L,the intra-day relative standard deviations were 0.8?2.3%,the inter-day relative standard deviations were2.8?4.2%,and the recovery rates of standard addition were 89.1?104.4%.The results showed that the method was simple,rapid,green and environmentally friendly with good linear relationship and low detection limit and relative standard deviation,and was suitable for the detection of phenolic acids in Shanxi vinegar.2.The liquid-liquid micro-extraction technology was combined with high performance liquid chromatography to establish a method for detecting the content of flavonoids in Shanxi vinegar.The effects of the type and volume of the extractant,vortex time,centrifugation time and salt ion strength on the extraction effect were investigated.This method was successfully applied to the determination of 7flavonoids in 17 vinegars of 5 brands,and the relationship between flavonoids content and vinegar aging years was analyzed.The results showed that the content of flavonoids in these vinegar samples was positively correlated with the age of aging.The linear ranges of the seven flavonoids were 0.2?20?g/m L,the correlation coefficients R~2were 0.99006?0.99987,the detection limits were 0.02?0.08?g/m L,and the quantification limits were 0.07?0.23?g/m L,the intra-day relative standard deviations were 0.57?1.89%,the inter-day relative standard deviations were1.51?3.83%,and the recovery rates of standard addition were 83.1?116.8%.The method used a hydrophobic deep eutectic solvent as the extractant,which had the advantages of small dosage,short extraction time,high enrichment multiple and high sensitivity,and was suitable for detecting the content of flavonoids in Shanxi vinegar.3.The hydrophobic eutectic solvent synthesized by quaternary ammonium salt-n-decanoic acid was used as the extractant.Liquid-liquid microextraction combined with high performance liquid chromatography was used to determine the content of the marker ligustrazine in Shanxi vinegar,which greatly reduced the use of organic reagents.Some important factors affecting the extraction efficiency of ligustrazine have been optimized,including the type and amount of extractant,the molar ratio of HBA to HBD,vortex time,centrifugation time,and the amount of Na Cl addition.Under optimized conditions,the linear range of this method was 0.2?20?g/m L,the correlation coefficient R~2was 0.98941,the detection limit was 0.14?g/m L,the quantification limit was 0.43?g/m L,the intra-day relative standard deviation was 2.8%,and the inter-day relative standard deviation was 3.4%,and the recoverys of standard addition were 98.47?99.38%.This method provides a new idea for the extraction of trace analytes from complex food matrices.