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Attempts to separate (–)‐α‐thujone, (+)‐β‐thujone epimers from camphor enantiomers by enantioselective HPLC with polarimetric detection
Author(s) -
El Montassir Dahmane,
Aamouche Ahmed,
Vanthuyne Nicolas,
Jean Marion,
Vanloot Pierre,
Taourirte Moha,
Dupuy Nathalie,
Roussel Christian
Publication year - 2013
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201200907
Subject(s) - chromatography , chemistry , camphor , enantiomer , epimer , high performance liquid chromatography , chirality (physics) , elution , stereochemistry , organic chemistry , chiral symmetry breaking , physics , quantum mechanics , nambu–jona lasinio model , quark
In a first step, 26 chiral stationary phases (CSPs) have been screened for the separation of (–)‐α‐thujone, (+)‐β‐thujone epimers and camphor enantiomers by LC. The separations were monitored by a polarimeter detector. None of these CSPs provided a noticeable resolution for camphor enantiomers. The three components of a test mixture were clearly baseline separated on Chiralpak AS‐H, Chiralpak AZ‐H and TCI‐MBS (poly( N ‐alpha‐( S )‐methylbenzylmaleimide) coated on silica gel) in a mobile phase composed of hexane/2‐PrOH (99:1 v/v). Interestingly, for a preparative application, the three CSPs produced different elution orders for the three constituents of the mixture. In a second step, it is shown that the use of online polarimetric detection constitutes an unprecedented method to reveal the occurrence and the relative content of thujone epimers and the chirality of the major camphor enantiomer in crude essential oils. A proof of concept is illustrated on crude essential oils from Rosmarinus tournefortii, Artemisia herba alba and A. arborescens, which grow in Morocco and have several traditional uses there. In a third step, pure (+)‐β‐thujone was quantitatively collected from A. arborescens crude oil by semi‐preparative HPLC on Chiralpak AZ‐H monitored by a polarimeter.