Chiral gc analysis of menthone and isomenthone with high enantiomeric purities in laboratory‐made and commercial essential oils

Direct separation of the enantiomers of the two diastereomers, menthone and isomenthone, was performed using an octakis‐(3‐O‐butyryl‐2,6‐di‐O‐pentyl)‐α‐cyclodextrin phase. Enantiomerically pure (—)‐menthone and (+)‐isomenthone were detected in many oils of Mentha, Micromeria fruticosa (L.) Druce and Calamintha incána (Sm.) Heldr. High enantiomeric purities of (+)‐menthone and (—)‐isomenthone were detected in commercial and freshly distilled geranium oils.