摘要
目的以甘草酸溶液为例,基于动态法测量沸点-饱和蒸气压的理论,以此来探讨不同浓度条件下甘草酸溶液的沸点-饱和蒸气压的关系,构建甘草酸溶液浓度-沸点-饱和蒸汽压间的函数关系,为中药浓缩过程的相关工艺研究提供实验数据和理论依据。方法采用UPLC法测定不同质量分数下甘草酸溶液中的甘草酸质量浓度;采用铂金板法测量不同质量分数下甘草酸溶液的表面张力;基于动态法对不同质量分数条件下的甘草酸溶液的沸点-饱和蒸汽压进行测量。结果原始浸膏中甘草酸质量浓度为99.25 mg/m L,约占总固体可溶物的21.5%,其稀释过程充分均匀,符合梯度比例;当溶液质量分数超过18%后,料液中就逐渐形成胶束,降低了溶液的表面张力;发现当环境压力稳定时,料液质量分数增加时,沸点会呈降低趋势;当料液温度不变时,随着料液质量分数的增加,溶液的饱和蒸汽压呈增长趋势,但在溶液温度313.0~343.0 K的此间范围内这两者间的相互作用趋势不明显。结论根据实验结果,构建了甘草酸溶液浓度-沸点-饱和蒸汽压三者间的函数关系,根据该方程可以发现,当维持浓缩真空度和加热能耗保持不变时,随着料液质量分数的增加,甘草酸浓缩液的温度会缓慢降低,而蒸发速率会适当加快。
Objective Based on the theory of dynamic method for measuring the boiling point-saturated vapor pressure, the functional relationship between the boiling point and saturation vapor pressure was studied for the glycyrrhizic acid solution. To build the relationship among the mass fraction of glycyrrhizic acid solution, boiling point and saturation vapor pressure, in order to provide the experimental data and theoretical basis for the related studies of traditional Chinese medicine concentration process. MethodsThe concentration of glycyrrhizic acid was determined by UPLC for different concentration of glycyrrhizic acid solution. Also, the surface tension of glycyrrhizic acid solution was measured by platinum plate method. Based on dynamic method, the boiling point was measured with the changing saturated vapor pressure at the different mass fractions of solution. Results The concentration of glycyrrhizin in the original extract was 99.25 mg/m L, which accounted for 21.5% of the total solid soluble substance. The dilution process is fully even and conforms to the gradient ratio. When the solution mass fraction was more than 18%, the micelle was formed gradually in the liquid, reducing the surface tension of the solution. It can be found that the boiling point showed the downward trend with increasing solution concentration of glycyrrhizic acid, while the pressure was maintained constant in the environment. When the temperature of solution was hold constant, the saturation vapor pressure of the solution increased with increasing solution concentration of glycyrrhizic acid, but the trend of this interaction was not obvious between the temperature range（313.0—343.0 K）. ConclusionAccording to the experimental results, the functional relationship among the concentration, boiling point and saturated vapor pressure of glycyrrhizic acid solution was constructed. While maintaining the concentration vacuum and the heating energy consumption unchanged in the production process, the glycyrrhizic acid solution temperature should slowly decrease and the evaporation rate should be moderately accelerated with the increasing mass fraction of solution.
出处
《中草药》
CAS
CSCD
北大核心
2018年第1期142-150,共9页
Chinese Traditional and Herbal Drugs
基金
天津市科委项目(15PTCYSY00030
16ZXHLGX00170)
关键词
甘草酸
浓缩过程
沸点
饱和蒸汽压
表面张力
UPLC
胶束
glycyrrhizic acid
concentrated process
boiling point
saturation vapor pressure
surface tension
UPLC
micelle
