Statistical theory of multiple-site linear wall-adsorption capillary Chromatography.
Based on the mass-balance principle, a particular diffusion equation to describe the movement of solute molecules in the stagnant layer of multiple-site solid surfaces is constructed. From the equation, the moments of residence time in a step on multiple-site surfaces are derived. Similarly, the moments in a step in the mobile phase are also derived from a diffusion-drift equation. According to the probability theory, there exists a general relationship between the moments of an elution curve and the moments in a step. Through this relationship, the expressions of the elution-curve moments are derived from the step moments. In this paper, the details related to multiple-site linear wall-adsorption capillary chromatography are described and added in the equations to determine the step moments. The resultant expressions of the elution-curve moments involve various factors, such as adsorption-desorption rate constants, equilibrium constants, axial and radial dispersions in the mobile phase. Afterwards, the moment expressions are used to analyze the peak tailing. The results show that a small quantity of sites with a slow desorption rate will lead to a large peak asymmetry.
Chen
Yinliang
Y
Institute of Nuclear Physics and Chemistry, Chinese Academy of Engineering Physics, Mianyang, Sichuan 621900, China. chen_yinliang@hotmail.com
Tang
Yuanming
Y
D000327:Adsorption; D000465:Algorithms; D002845:Chromatography / Q000379:methods* / Q000706:statistics & numerical data*; D008956:Models, Chemical; D015233:Models, Statistical; D016011:Normal Distribution; D013499:Surface Properties