基于分离粒子随机扩散理论的色谱模拟

Theoretical Simulation on the Chromatographic System Based on the Random Diffusion of the Separating Particles

为了对扩散分子的轨迹实施动态追踪与模拟,深入理解分子扩散对色谱动力学的影响,本文利用微尺度受限空间随机行走的模拟方法对色谱填充柱中的分子扩散过程进行了模拟.重点考察了固定相的填充率、固定相的形状和柱长对色谱动力学行为的影响.模拟结果表明短柱和大填充率具有较高的柱效;在相同的密堆排列下,固定相形状对分子扩散过程影响微弱;待分离粒子的运动表现出微尺度空间限域的扩散特征,但粒子的流动行为会随外部压力的增大而增加.本论文提出的模拟方法对于发展高效能色谱,开发新型分离技术等具有参考意义.

In order to dynamically track the trajectory of diffusing molecules in a chromatography system, and to thoroughly understand its influence on chromatographic dynamics, we have developed software based on the framework of random walks in a confined space, with which the diffusion processes have been simulated. The influence of the filling rates, the form of the stationary phase, and the column length of a packed column on the chromatographic dynamics have been discussed based on these simulation results. It was concluded that shorter column lengths and larger filling rates result in a higher column efficiency. The particles to be separated normally show basic diffusion characteristics in the confined space. However, their flow behavior will increase with increasing external pressure. The simulation results indicate that the influence of the filling rate of the stationary phase and the column length on chromatographic dynamic behavior is similar to those seen in experiment, whereas the form of the stationary phase only has a slight effect because of the same close-packed barrier arrangement. This simulation method we proposed has some significance for the development of high-performance chromatography and novel separation technologies.