Miyabe K, Guiochon G
Department of Chemistry, The University of Tennessee, Knoxville 37996-1600, USA.
J Chromatogr A. 2000 Sep 8;891(2):217-33. doi: 10.1016/s0021-9673(00)00656-7.
The influence of the column radial heterogeneity on the determination of equilibrium isotherm data by the elution by characteristic point (ECP) method is studied using nondimensional numerical calculations and taking into account typical radial distributions of the mobile phase flow velocity and the column efficiency across a column. Overloaded elution peaks were calculated with the equilibrium-dispersive model as a function of four dimensionless parameters, the number of theoretical plates at the center of the column, the Langmuir equilibrium constant, the retention and the loading factors. The influence of the mass transfer resistances and the radial heterogeneity of the column on the ECP data was analyzed by comparing the true isotherm and the one estimated from the diffuse profile of overloaded peaks. The results provide information on the accuracy of the ECP method. The error made increases with increasing degree of radial heterogeneity. This error can be corrected by using the results of the nondimensional numerical calculations, allowing a further extension of the applicability of the ECP method.
采用无量纲数值计算方法，考虑柱内流动相流速和柱效的典型径向分布，研究了柱径向非均质性对特征点洗脱法（ECP）测定平衡等温线数据的影响。使用平衡分散模型计算过载洗脱峰，作为四个无量纲参数的函数，这些参数包括柱中心的理论塔板数、朗缪尔平衡常数、保留因子和负载因子。通过比较真实等温线和从过载峰的扩散轮廓估计的等温线，分析了传质阻力和柱径向非均质性对ECP数据的影响。结果提供了关于ECP方法准确性的信息。误差随着径向非均质性程度的增加而增大。通过使用无量纲数值计算的结果可以校正此误差，从而进一步扩展ECP方法的适用性。
