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制备色谱通过放大可以直接作为工业规模的分离工具。因此,制备色谱分离参数的优化具有重要意义。在实用中最关键的操作参数是进样浓度、进样体积与流动相流率,尤其是前两者直接左右生产效果。在高浓度情况下,色谱呈非线性,而天然产品的精细分离中,原料样品是多组分的。研究非线性多组分条件下,色谱分离参数的优化方法十分必要。在生产中,柱放大的综合效果除纵向扩散与相间传质阻力外,还因柱径增大流速分布不均引起谱带展宽,均体现在塔板高度的变化。因此需要测定板高与流速的关系曲线,分析板高对工作参数优化的影响。本研究以茶多酚原料中的表没食子儿茶素没食子酸酯(EGCG)为优化分离对象,在非线性多组分色谱模型的基础上,通过人工补偿逆方法及二组分近似拟合确定多组分的非线性吸附等温线,进而以EGCG的生产率为优化目标函数,以EGCG产品的一定纯度和回收率为限制条件,结合板高的影响确定工作参数的初值与变化区间,进一步应用“二分法”优化进样浓度、进样体积和流动相流率等工作参数,得出非线性及非理想非平衡条件下分离EGCG的最佳操作条件,优化结果与实验结果较符合。
Preparative chromatography can be used directly as an industrial-scale separation tool by amplification. Therefore, the preparation of chromatographic separation parameters optimization is of great significance. In practice, the most critical operating parameters are the injection concentration, injection volume and mobile phase flow rate, especially the first two direct effects of production. In the case of high concentrations, the chromatogram is non-linear, whereas in the fine separation of natural products, the raw sample is multicomponent. Under the condition of nonlinear multicomponent, it is necessary to optimize the parameters of chromatographic separation. In production, the combined effect of column amplification is not only longitudinal diffusion and interphase mass transfer resistance, but also spectrum broadening due to the uneven distribution of flow velocity due to the increase of column diameter, which are reflected in the change of plate height. Therefore, it is necessary to determine the relationship between plate height and flow rate and analyze the effect of plate height on the optimization of working parameters. In this study, epigallocatechin-3-gallate (EGCG) in tea polyphenols as the optimal separation target, on the basis of non-linear multi-component chromatographic model, by artificial compensation inverse method and approximate fitting of two components Multi-component non-linear adsorption isotherm, and then to EGCG productivity as the optimization objective function to EGCG product purity and recovery rate as a constraint, combined with the impact of plate height to determine the initial value of the working parameters and the change interval for further application “Dichotomy ” to optimize the injection concentration, injection volume and mobile phase flow rate and other working parameters, obtained non-linear and non-ideal conditions for the separation of EGCG best operating conditions, the optimization results and experimental results more in line.