Study On Separation And Purification Of Sapindus-saponin

Separation of the sapindus-saponin from natural sapindus pericarps is very difficult, a rapid and simple determination method for total-sapindus-saponin is not founded. For solving these problems, some new separating technologies, such as ultrafiltration and foam separation, are applied to purify the sapindus-saponin.The content of total sapindus-saponin was determined by spectrophotometry at 478nm, and the optimal determination conditions for sapindus-saponin were: 5%(wt%) vanillin-acetic acid was used as chromogenic reagent, perchlorate was used as oxidant, acetic acid was used as solvent, their dosages were 0.4ml, 1.4ml, 10ml, respectively. The mixture solution was heated at 70℃for 20min, then cooled at 0℃for 3min. A good linear relationship in the range from 100μg to 300μg of the total sapindus-saponin was found. A standard curve equation was y =-0.064＋0.00388x, R=0.9996.When the volume ratio of chitosan-acetic acid liquid to extraction aqueous solution was 2.0%, the effect of pretreatment was better. The results of the ultraflltration membrane orthogonal experiments indicated that under the condition of membrane intercepting molecular weight 20～50K, pH 4.8, 25℃, the cross-flow velocity 2.78×10^-5m/s, 0.08MPa, the purity of saponin-supindus was 67.02% after ultrafiltration. The purity of saponin-supindus was 72.42% by ultrafiltration of 6K membrane. The experimental results showed that the initial feed concentration, gas flow rate, volume of the initial solution, pH of the solution, temperature, and the gas sparger's aperture all have obvious effects on the foam separation of sapindus-saponin. The optimal conditions of the orthogonal-experiment about foam separation were: the initial concentration of sapindus-saponin was 2.5g/L, the gas flow rate was 0.9L/min, the temperature was30℃, pH of the solution was 4.8. Under those conditions, the purity of the saponin-supindus reached to 66.24%, and the enrichment ratio was 2.48.These results showed that ultra_filtration and foam separation were simple, relatively inexpensive processes, and had some potential application for purification of sapindus-saponin.