Purification Of Glycyrrhizic Acid By Solvent Extraction Coupling Macroporous Resin Adsorption

Although solvent extraction has the features of low cost, simple operation and large throughput, thepurity of product is too low to meet the market demand. In general, the efficiency of macroporousadsorption resin separation and purification is higher. This paper presents a method which combinessolvent extraction’s simple process and large throughput with macroporous adsorption resin method whichprevents impurity from blocking macroporous adsorption resin pore, reduces the amount of macroporousresin processing, prolongs service life and improves the resin purification efficiency. This study usedsolvent extraction coupled macroporous resin method for extraction and purification of glycyrrhizic acidtechnological process and purification conditions, taking licorice extract as raw material in XinJiang.This paper established UV-visible spectrophotometry and HPLC to analyze the licorice extractcontent determination method. However, the results of two determination methods had much difference.Using the ultraviolet spectrophotometric method, the operation is simple and quick but the data deviation islarge. The high performance liquid chromatography (HPLC) method operation is complicated but the datais accurate. To simplify the experiment procedure, in the solvent extraction experiments the preliminarypurify of glycyrrhizic acid used ultraviolet spectrophotometry to determine extraction rate of glycyrrhizicacid in the early procedure. During the experiment of macroporous adsorption resin S-8refiningglycyrrhizic acid, we chose high performance liquid chromatography to make results more accurate.Primarily glycyrrhizic acid was extracted and purified by solvent method. First, single factorexperiment and orthogonal experiment was investigated, respectively extraction time, extractiontemperature, solid-liquid ratio, fineness and extraction times. The experimental experiment conditions wereas follows: extracting time2.0h, extraction temperature80℃, solid-liquid ratio1:15, particle size of40mesh and extracting2times. The obtained optimum glycyrrhizic acid purity was54.01%, and theextraction yield was96.86%. Then glycyrrhizic acid crude products obtained from solvent method wasinvestigation by single factor experiment and orthogonal experiment of acetone extract method such asextraction time, solid-liquid ratio, extraction temperature, fineness and extraction times. The optimumtechnological conditions were as follows: reflux time2.0h, solid liquid ratio1:10, extraction temperature50℃, particle size60mesh and extracting3times. The obtained optimum glycyrrhizic acid purity was69.15%, and the extraction yield was95.42%. The optimal pH value of preparation glycyrrhizic acidtriammonium salt was7.5.Next,12kinds of resin was studied in adsorption and desorption rate of the glycyrrhizic acidtriammonium salt, the S-8macroporous adsorption resin was choosed to purify glycyrrhizic acidtriammonium salt in comparison with other resins and establish process routes of purification glycyrrhizicacid triammonium salt. The optimum parameters were as follows, sample concentration was4.0mg/mL, thepH of solution was7, liquid flow rate was2.0mL/min, and elution liquid flow rate was1.0mL/min. In theexperiment, at first70%ethanol was used to elute and remove impurities with5BV, then pH=2acetone was used to elute products from adsorpted resin with12BV. In the result, glycyrrhizic acid purity was92.38%, total yield of glycyrrhizic acid was81.09%. The static adsorption study shows that the Langmuirisotherm equation can be better described the adsorption of glycyrrhizic acid triammonium salt by S-8macroporous resin. Thermodynamics experiment showed that the adsorption of glycyrrhizic acidtriammonium salt by S-8macroporous resin is a spontaneous exothermic process. It belongs to the categoryof physical adsorption.