Research On Separation Methods Of Natural Products In Eutectic Solvents

Since deep eutectic solvents(DESs)were proposed by Abbott and others in 2003,they have attracted more attention to their many advantages(easy to synthesize,cheap,biodegradable,non-volatile,non-flammable,etc.)and become a new generation "Green solvents".In recent years,it has been widely used to efficiently extract natural products from organisms.However,separating natural products from extracts is still remaining problem.Therefore,it is important to develop a complete technology for extracting and separating natural products.By combining DESs with mechanochemical extraction(MCE),microwave-assisted extraction(MAE),or heat-asisted extraction(HE),the processing time and the extraction of samples is significantly reduced,.After that,the high-efficiency separation of natural products was achieved by changing the chemical action of DESs with the adsorbent and the target.The specific content is as follows:1.By adjusting the amount of water,temperature,p H and salinity to destroy the hydrogen bonding structure in DESs,myricetin(MYR),quercetin(QUE),naringenin(NAR),kaempferol(KAE)and isorhamnetin(ISO),the five flavonoids,were successfully separated from the DESs solution.Subsequently,taking Flos Sophorae as an example,QUE,KAE and ISO were extracted from Flos Sophorae using DESs-MCE method,and MIL-100(Cr)was used as the adsorbent for separation,and the target was eluted with methanol.Finally,quantitative analysis was performed by UPLC: Under the optimal conditions,the recoveries of QUE,KAE and ISO were 72.7%,89.2% and 90.3%,respectively.At the same time,the method can be used in combination with AP / MALDI-MS to make the established analysis method greener,faster and more convenient.In addition,a link between nucleic acids and DESs has been established,which may break the barrier between solvent molecules and biomolecules.2.Silica gel modification is achieved by grafting functional groups on the surface of silica gel for recovery of natural products.In this experiment,rhubarb was used as an example for the test.The DESs-MAE method was used to extract four anthraquinone compounds in rhubarb,and then phenyl,octyl,and amino modified silica gels were used as adsorbents to separate them,and then eluted with ethanol.Quantitative UPLC test results showed that the recovery rates of Aloe emodin,Emodin,Chrysophanol,and Physcion in Rhubarb were modified by modified silica gel.85.92% and 90.76%.This experiment found that phenyl and anthraquinones have good adsorption,which provides a new idea for finding suitable adsorbents to recovery natural products.3.In order to explore the hydrogen bonding rules in different types and concentrations of DESs and find a better method for the separation of natural products,this experiment takes Flos Sophorae as an example to find the changing rule of chemical bonds in DESs from a micro perspective,and take DESs-MCE,DESs-MAE and DESs-HE extraction methods for comparative analysis.