The Membrane Separation Rule Study For Acid And Alkaline Components Of Traditional Chinese Medicine Based On Compound-Associative State

The components in the solution of traditional Chinese medicine are complex and interact with each other.They exist in many forms,such as free state,ionic state,free-ionic state,acid-base complex salt and associative state,which change the membrance separation behavior,affect the quality uniformity of preparation,and lead to the decline in the applicability of membrane separation technology.In this study,single component solution and complex solution were used to explore the correlation between the existing state of components and membrane separation behavior..In the experiment,the representative phenolic acids,flavonoids,alkaloids and saponins were used to change the acidity and alkalinity of the solution and regulate the existing state of the components.It was found that with the increase of pH value,phenolic acids gradually changed from free state to ionic state,and the transmission of nanofiltration membranes decreased significantly.For example,the transmittance of gallic acid decreases by more than 40%and caffeic acid decreases by more than 60%.Therefore,pH value affected the dissociation state of components and thus affected the separation behavior of membranes.The transmittance of alkaloids in the ultrafiltration separation process is above 90%,so the applicability is not strong.The separation mode of nanofiltration is determined by charge effect,dissolution-diffusion effect and the existing state of components.The surface energy of free flavonoids is high,and the stability of solution can be improved by molecular association or membrane adsorption.Therefore,the membrane adsorbability is serious.The dissociated flavonoids are screened and filtered in the form of single molecule,the transmittance is more than 90%.With the change of pH from 3 to 8,the transmittance of saponins increased from 40%to 87%.The change of micelle’s state of existence leads to the change of permeation behavior.Phenolic acid-alkaloid,alkaloid-phenolic acid,alkaloid-flavone,acidic saponin-alkaloid were combined with each other,and different compatibility ratios were adjusted to prepare acidbase double salts and associations so can simulate the diversified existence of complex solutions.Low-field NMR,high-field NMR and ultraviolet spectrophotometry were selected for characterization,and membrance separation rule was also used to analyze and explore the separation law of components in complex solution environment.Low-field nuclear magnetic resonance(LF-NMR)technique is used to detect the relaxation hydrogen of associative hydrogen protons,which shows that the strong hydrogen bonded protons have special relaxation characteristics,thus proving the feasibility of LF-NMR in detecting the existence of associative states.The functional groups of the complexes were changed due to the change of the existing state of the complexes,which could be observed on the full-wavelength ultraviolet scanning spectra.In addition,the formation of hydrogen bonds in the complex will make the chemical shift of hydrogen shift to low field and the structure of the complex can be detected by high field nuclear magnetic resonance(HF-NMR).The larger the difference of dissociation constant(pKa)of compatible components is,the more obvious the component tends to exist in the form of complex state,and the more obvious the membrane interception characteristics are.In the process of separation,the compatibility between solution and membrane module is the precondition to standard the application of membrane separation.In this study,the surface morphology of membrane soaked with acetone,acid-base solution and organic reagent was analyzed by scanning electron microscopy,and the pore size was measured by low-field NMR to evaluate the performance of membrane comprehensively.It was found that the order of stability of PES ultrafiltration membrane was methanol,acetonitrile,ethanol>acid water>alkali water>acetone.Membrane abscission was analyzed by liquid chromatography-mass spectrometry(LCMS).The main components were triethylamine,hydroxybenzoic acid,PEG polymer,nitrosopyrrolidine,n-butylamine,caprolactam,N-nitrosopyrrolidine and aminoheptanoic acid.The clear compatibility of membrane provides technical support for the safe and standardized use of membrane separation technology in traditional Chinese medicine preparations.The interaction between components after compatibility of traditional Chinese medicine compound can affect the extraction,separation and refining of effective components in the process of preparation of traditional Chinese medicine.This study on the correlation between the physicochemical properties and the existing state of solution components caused by the compatibility of traditional Chinese medicine prescriptions can provide new ideas and methods for the study of compatibility effect of traditional Chinese medicine prescriptions and the influence of pharmaceutical technology,which is of great significance to the clinical co-decoction,separate decoction and the formulation of production technology of traditional Chinese medicine decoctions.