High-performance liquid chromatographic investigation of the enantioselectivity and mechanism of chiral recognition of new cholic acid-based stationary phases

To elucidate the mechanism of chiral recognition of cholic acid-based stati onary phases, four new cholic acid derivatives, with differently substitute d carbamate or three acetoxy groups, were bonded to a hydrosilyl-modified s ilica gel. Their capacity to discriminate between enantiomers was evaluated in normal-phase high-performance liquid chromatography. The results were c ompared with those from equivalent separations on trihydroxy- and 3 alpha - phenylcarbamate-substituted cholic acid-based bonded phases. The influence of mobile phase composition on the separation of the enantiomers of amino a lcohols was shown. Different mechanisms of chiral discrimination are discus sed, highlighting the influence of the nature of the carbamate on enantiose lectivity.