Simplified mathematical model of irreversible sample adsorption in capillary zone electrophoresis

In this paper, a very simple mathematical model of the irreversible adsorption of a sample onto the capillary wall in capillary zone electrophoresis is investigated analytically and numerically. With it, the influence of adsorption on the transport of sample is studied. The advantage of the model is that it contains only one parameter while other models usually contain many more. Mathematically, the problem is reduced to the construction of a solution of a partial differential equation coupled to an algebraic equation that imposes some restriction on the solution. Great attention is paid to the formulation of a correct mathematical model of the process. In diffusionless approximation, an analytical solution is obtained, while the influence of diffusion is studied by computer simulation. It is shown that in diffusionless approximation, the qualitative results regarding the behavior of the sample zone have a rather general character and do not depend on the specific mechanism of interaction between the substance and the wall.