Characterization of PS-co-DVB Monolithic RP Column Using LSER Theory and Lipophilicity Determination

Tal C. Klein, The institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
Eli Grushka, The Institute Of Chemistry, The Hebrew University Of Jerusalem, Jerusalem, Israel

The present research characterizes Polystyrene cross-linked with DiVinylbenzene monolithic chromatographic column.  Unlike packed Silica columns the monolithic column is stable over a wide range of pH and it can yield better efficiencies with no need of high pressure. The characterization of the monolithic column is accomplished by using the Linear Solvation Energy Relation (LSER) theory and by obtaining the lipophilic nature of the monolith.  LSER is a statistical model that uses multivariate linear regression to express the column properties taking into account intermolecular interactions between the solute and the chromatographic system. These parameters include hydrogen bonds, dispersion and polar interactions. The change in free energy due to interactions mentioned above is measured according to

Abraham's equation:

Log k' = vV + eE + sS + aA + bB + c

Whereas the capital letters stand for the solute descriptors and the lowercase letters stand for system constants and c is the intercept obtained by linear regression.

The lipophilic nature of the monolithic column is determined by comparing shake-flask partition coefficients with the chromatographic retention factor. We then use the LSER model to compare whether those interactions that cause the retention on the monolith are correlated with the factors for partition in Octanol/ Water systems.