A mathematical model for hydrodynamic and size exclusion chromatography of polymers on porous particles

When packed columns filled with porous particles are used for the separation of macromolecules, either size exclusion chromatography (SEC), hydrodynamic chromatography (HDC), or a combination of both determine the macromolecule retention mechanism. This paper develops a simple mathematical model to describe a molecular weight calibration graph, which includes both HDC and SEC. There is a transition between the HDC calibration region at higher molecular weights to an SEC region at lower molecular weights. The degree to which SEC and HDC are mixed depends on the particle diameter, the relative size of the pores, and the macromolecule size. In addition, using fractal considerations, the fractal character of the apparent selectivity between two adjacent peaks on the chromatogram is shown. This model constitutes an attractive tool to enhance the expansion of these two chromatographic techniques for the separation of biological or synthetical macromolecules.