Construction And Application Of Small Molecular Alcohols-tartrate Salts Aqueous Two Phase System

An aqueous two phase system（ATPS）,also known as an aqueous biphasic system,is a new and green liquid-liquid extraction（LLE）system that has been widely applied in the separation and purification of biomolecules.The ATPS could be composed of polymer-polymer ATPS,the polymer-salt ATPS,the ionic liquid-salt ATPS and micromolecule organic solvent-salt ATPS.Because the price of ionic liquid is higher,the viscosity of polymer is larger and the inorganic salt is hard to degradate,the application of these types of ATPS in large-scale industrial production was affected.The aim of this paper is to estabilish the small molecular alcohols-tartrate salts ATPS which will be applied to sepration and purification of natural products.（1）The solubility of tartrate salt in water is the precondition of phase formation.On the basis of analyzing the solubility of seven kinds of tartarate salts,potassium tartrate and potassium sodium tartrate were selected as phase-forming salts.Binodal data for ethanol/1-propanol/2-propanol+C₄H₄O₆K₂/C₄H₄O₆KNa+water systems were experimentally determined,respectively.The phase-forming abilities of small molecular alcohols were discussed by the effective excluded volume of salt and the location of the binodal curves plotted in molality.The phase-forming abilities of the investigated alcohols followed the order:1-propanol>2-propal>ethanol.The salting-out abilities of the tartrate salts were discussed by the effective excluded volume of salt,gibbs energies of hydration and the location of the binodal curves plotted in molality.The salting-out abilities of the investigated salts followed the order:C₄H₄O₆KNa>C₄H₄O₆K_2.Different TLL and M_R influenced the distribution of the target components in the two phases.In this study,1-propanol-C₄H₄O₆KNa ATPS which included four TLL and three M_R was designed by combining the MATLAB software with the liquid-liquid equilibrium data.（2）In this study,the partition behavior of dihydromyricetin in ATPS composed of1-propanol and C₄H₄O₆KNa was evaluated.This evaluation was performed en route to establishing an ATPS extraction system for the recovery of dihydromyricetin from the leaves of Ampelopsis grossedentata.System parameters including TLL,M_R and product concentration were studied using model（purified dihydromyricetin）and complex systems（Ampelopsis grossedentata extracts）.The results showed that the recovery of dihydromyricetin increased with the increase of M_R when the TLL was fixed,and the recovery of dihydromyricetin increased with the increase of TLL when the M_R was fixed.For complex systems,the best result was observed in system with TLL=70 and M_R=3for Ampelopsis grossedentata extracts（87.93%recovery and 64.25%purity）.（3）In this paper,1-propanol-C₄H₄O₆KNa ATPS was used to separate phloridzin from Lithocarpus polystachyus（Wall.）Rehd.The content of phloridzin in alcohol phase was measured by HPLC and the recovery was calculated.The effect of different TLL and different M_R on the recovery of phloridzin was discussed.With a gradient elution method,a suitable purification process of phloridzin was performed on dynamic axial compression packed with macroporous adsorption resin D101.Performing a gradient elution by 10-50%（v/v）ethanol aqueous effectively separated the phloridzin from extracts with the recovery and purity of 93.26%and 48.16%.The phloridzin extract was subjected to chromatographic column on polyamide resin,after simple optimization of elution conditions for polyamide resin,the recovery and purity were 83.18%and 57.66%;When the phloridzin extract was subjected to chromatographic column on ODS,mobile phase ratio,sample loading and flow rate were employed to optimize the procedure in the study.The results showed that when the sample loading was 20 mg,the flow rate was 24ml/min and the mobile phase was methanol:water=34:66,the purity and R were99.09%and 1.7343,respectively.