随着中药生产行业的转变, 中药生产过程现代化成为了必然趋势。 而目前由于缺乏有效的在线检测手段, 中药生产检测滞后性大, 产品质量参差不齐。 针对中药提取过程在线监控及终点判定的问题, 基于朗伯比尔定律及中药提取动力学方程建立提取液紫外吸光度随时间变化模型, 并提出动态分析及终点判断方法, 该方法包括紫外吸光度序列拟合、 稳健性分析以及终点计算。 以千年健提取过程为例, 使用本实验室自主研发的中药提取液在线采样系统进行光谱收集, 并对离线样本求取其有效固体物质含量作为参考。 分析过程中, 首先对实时检测的光谱进行插值及滤波处理, 计算2302～400 nm紫外谱区的吸光度均值并结合前期数据组成吸光度均值序列; 随后, 进行了该吸光度序列与提取液固体含量之间的相关分析, 得到线性相关系数r2=09828, 证明二者存在较强的线性关系; 最终对吸光度均值序列进行动态模型稳健回归及提取终点判定。 结果表明: 回归过程通过稳健性分析能够充分识别出测量异常点, 提高了拟合曲线与原始吸光度的复相关系数, 使其达到099, 并通过终点判定将千年健提取时间由最初人工设定的180 min缩短至122 min。 实验证明, 紫外在线监控方法实现了提取过程的在线监控及终点判定, 对稳定产品质量、 提高经济效益具有重要意义。

With the transition of Chinese traditional medicine manufacture industry, modernization has become the inexorable tendency in its future development. However, during the current Chinese traditional medicine producing process, the lack of online monitoring leads to the lagging of quality detection, as well as quality differences between products. In this paper, aiming at realizing online monitoring and end point automatic determination for Chinese traditional medicine (CTM) extraction unit, which is one of the most important units in CTM producing, ultraviolet (UV) spectroscopy is applied to build UV absorbance dynamic model based on the Lambert-Beer law and the CTM extraction kinetic model which presents a new method of UV absorbance dynamic analysis and endpoint determination, including curve regression, robustness analysis and endpoint calculation. In the experiment for online monitoring homalomena occulta extraction, the online UV spectral collection system for CTM extraction, developed by our laboratory, was applied for spectral collection; meanwhile, solid component contents in the offline samples were measured as reference. During the analysis, first of all, we pretreated the spectrum collected in the current period with interpolation and smoothing, and calculated the mean value within a UV region of 2302～400 nm to form an absorbance mean value sequence with data obtained in the early measurements; then we verified the linear correlation between the sequence of absorbance and the concentrations of effective component in the solution, the linear correlation coefficient equals 0982 8, showing a high linearity between UV spectra and solid component contents; finally, we regressed the absorbance mean value sequence with the dynamic model, analyzing its robustness and the extraction endpoint. Experimental results demonstrate that, the robustness analysis could recognize the bad points of measurement during the regression process, and improve the consistency between the regression and the original curves, raising its squared correlation coefficient to more than 099; meanwhile, with endpoint determination, we shortened the homalomena occulta extraction process from the original manually set 180 to 122 min effectively. The experiment above proves that this method with UV spectroscopy realizes online monitoring and automatic endpoint determination for the CTM extraction process, and is of significant importance for stabilizing production as well as improving economic benefit.