Selectivity tuning and molecular modeling of new generation packings for RP HPLC

Retention mechanism, selectivity and physicochemical properties together wi th theoretical surface simulation experiments of laboratory-synthesized pac king materials for high performance liquid chromatography (HPLC) containing cholesterol molecules immobilized on the high quality silica gel were stud ied. The chromatographic behavior of the three cholesterol-based columns (S G-CHOL, SG-MIX CHOL/AP and SG-10-CHOL) was examined with special regard to retention and selectivity and compared to reference materials: a typical oc tadecylsilica column (SG-C18) and an alkylamide bonded phase (SG-AP). Tempe rature investigations (DSC) and molecular modeling simulations didn't bring an expected confirmation of liquid crystalline properties of materials stu died. The observed phase transition was attributed to conformation change w ithin the amide bonding.