Porous monoliths consist of a single piece of porous material with highly interconnected open channels resulting in convection to be predominant transport mechanism. Adsorption of molecules takes place on the channel walls. Since dynamic binding capacity is frequently proportional to the surface area formed in monoliths by channel walls, it seems that it would be possible to estimate dynamic binding capacity for monolith having particular pore size on the base of pressure drop measurement on the monolith. We developed a mathematical correlation and confirmed its validity for different molecules like proteins and plasmid DNA on monoliths having different pore size. Results are presented in first part of this work.

Adsorption of the molecules on pore walls results in a decrease of pore diameter and porosity, what causes an increase of the pressure drop during loading of the sample. Based on these assumptions one can derive mathematical correlation to calculate layer thickness formed by adsorbed molecules from a pressure drop data. Such equation however requires, besides assumption of particular monolith structure, also data of monolith porosity and pore diameter, especially later being difficult to be determined accurately what limits general applicability.

In the present work we derived equation for determination layer thickness formed by adsorbed molecules where no information about the monolith pore structure and size is needed. This allows accurate determination of adsorbed layer thickness in real time as a result of adsorption of the target molecules simply from measurements of pressure drop and several examples will be demonstrated.

References:
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2. Smrekar F., Ciringer M., Štrancar A., Podgornik A. Characterisation of methacrylate monoliths for bacteriophage purification. J. Chromatogr., A, 1218 (2011) 2438-2444.
3. Podgornik A., Etzel M.R., Smrekar V. Determination of layer thickness. PCT/SI2013/000033, 29.5.2013.