The separation of enantiomers of ten chiral arylpropionic acid derivatives was studied on six different polysaccharide-based chiral HPLC columns with various normal-phase eluents. Along with the successful separation of analyte enantiomers, the emphasis of this study was on the effect of the chiral selector and mobile phase composition as well as of the separation temperature on the elution order of enantiomers. The interesting phenomena of reversal of enantiomer elution order function of the polysaccharide backbone (cellulose or amylose), type of derivative (carbamate or benzoate), nature and position of the substituent(s) in the phenylcarbamate moiety, the polar modifier of the mobile phase (ethanol or 2-propanol), its content in the mobile phase, and separation temperature were investigated. In addition, an unusual increase in retention with increasing temperature was observed for some arylpropionic acid derivatives.

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When polysaccharide-based chiral columns are used in combination with aqueous-organic mobile phases for the separation of enantiomers in high-performance liquid chromatography the separation mode is commonly called "reversed-phase" in analogy to achiral separations. In several earlier and recent studies on neutral and basic chiral analytes it was shown by our and other groups that due to multiple type of interactions involved in selector-selectand binding and enantioselective recognition with polysaccharide derivatives, the above mentioned separation system may not always behave like a reversed-phase system. In the present study additional examples of non-reversed-phase behavior are described for the first time for weak acidic chiral analytes. In addition, the reversal of enantiomer elution order was observed again for the first time for several analytes based on water-content in the mobile phase.

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