Evaluation of a penicillin G acylase-based chiral stationary phase towards a series of 2-aryloxyalkanoic acids, isosteric analogs and 2-arylpropionic acids

The chiral recognition properties of a new chiral stationary phase based on immobilized penicillin G acylase were investigated using 35 acidic racemates. Twenty-seven compounds were resolved with high separation factors. The influences of mobile phase pH, type of organic modifier and ionic strength on enantioselective retention were studied. The most important tool for affecting the enantioselectivity was the mobile phase pH and interestingly the retention order of the enantiomers of some analytes could be controlled by this parameter. The analysis time for resolving enantiomers could be adjusted with a minor decrease in enantioselectivity using a high ionic strength mobile phase buffer while both retention and enantioselectivity decreased by adding organic modifier to the mobile phase. Displacement studies have demonstrated that the enzymatically active site and the chiral adsorption site overlap.