HPLC Separation of Enantiomers of Some Chiral Carboxylic Acid Derivatives Using Polysaccharide-Based Chiral Columns and Polar Organic Mobile Phases

The separation of enantiomers of 14 chiral carboxylic acid derivatives was studied on six different polysaccharide-based chiral columns in high-performance liquid chromatography with methanol, ethanol and acetonitrile as mobile phases with emphasis on the elution order of enantiomers. Some interesting examples of enantiomer elution order reversal were observed as a function of the nature and composition of chiral selector and mobile phase. For instance, the enantiomer elution order for carprofen, ketorolac, naproxen, proglumide and surprofen reversed with changing the chemical structure of the chiral selector. Also, the enantiomer elution order for carprofen, ketorolac and naproxen changed by varying the composition of the mobile phase. In addition, the interesting effect of column temperature on the retention and separation of some analytes was observed. For instance, the enantiomers of surprofen were only partially resolved at lower temperatures but baseline resolved at higher temperature.