Studies On The Adsorption And Desorption Actions Of Ginkgo Flavonol Glycosides On Adsorbent

More systemic and basal academic studies have been carried through which is about the adsorption and desorption actions of ginkgo flavonal glycosides on different polarity and structure adsorbent.Five adsorbents with different polarity and structure have been selected. The equilibrium speed, adsorption capacity, desorption ratio of ginkgo flavonol glycosides on these adsorbents as well as the influence of pH and temperature were studied in the way of static adsorption. Results indicate: (1) the relation of adsorption capacity of these adsorbents showing for ginkgo flavonol glycosides is D140A>D140>polyamine >ADS-17>ADS-7; the relation of desorption ratio is D140A>D140> ADS-17>ADS-7 >polyamine; (2) it was firstly found that the process of the adsorption of ginkgo flavonol glycosides on different adsorbents is a endothermic process through study in 15~-40#. (3) adsorption of the flavonol glycosides on non-polar and middle polar adsorbents are influenced much less than polar adsorbents by pH and temperature; the adsorption capacity of polar adsorbents increase greatly according to the raising of pH and temperature;The mechanisms of the adsorption and desorption of ginkgo flavonal glycosides on different adsorbents were discussed, and reasons why different adsorbents show difference for flavonal glycosides in the equilibrium speed, adsorption capacity, desorption ratio as well as the influencing degree of pH and temperature were analyzed, by studies of structures (function group, pore diameter, surface area etc.) using IR-spectra and surface area mensuration. It was found out that: (1) flavonal glycosides are eluted more easily on the non-polar and middle polar adsorbents than on polar adsorbents and little influenced by pH and temperature, because they are mainly adsorbed by their hydrophobic parts. (2) great changes of the adsorption capacity of polar adsorbents following to pH and temperature are due to plentifulhydrogen bonding adsorption. (3) according to ginkgo flavonal glycosides, the surface area of polymer adsorbent is usually much more important than the polarity, and non-polar adsorbent with high surface area shows good adsorption capacity especially when it has phenyl, but the polarity of adsorbents become the most important effect while raising of pH and temperature.On the other hand, accordant results in some aspects have been gotten in dynamic experiment. It was found out in gradient elution that: (1) most of ginkgo flavonal glycosides can be eluted by 50% ethanol solution from polymer adsorbents; adsorbents with polar functional group have better selectivity for flavonal glycosides, so the content of it is higher than non-polar and middle polar adsorbents. (2) pore diameter has purificatory function and micro-pores are in favor of increasing content of flavonal glycosides.This paper reveals that there are close relations between adsorption of flavonal glycosides and the polarity, surface area as well as pore diameter of adsorbent. Different polar adsorbents respectively have their own advantages that are stated above. Then proper adsorbent and corresponding conditions or combining of different adsorbents should be chosen on practical needs.Additionally, the production having 75 percents of ginkgo flavonal glycosides was obtained through simple condensation and precipitation of desorption solution which was gotten by desorption from D140 adsorbent.