Enantioselective analysis of monoterpenes in different grape varieties during berry ripening using stir bar sorptive extraction- and solid phase extraction-enantioselective-multidimensional gas chromatography-mass spectrometry.

The stereoisomeric ratios of various genuine metabolites of linalool (furanoid and pyranoid linalool oxides, hotrienol) and citronellol (cis- and trans-rose oxide) were determined in grape berries by means of enantioselective-multidimensional gas chromatography-mass spectrometry. Stereoisomers of the metabolites could be separated on a chiral column with a modified cyclodextrin as stationary phase. The detailed stereoselective analysis of the furanoid and pyranoid linalool oxides in the cv. Morio-Muskat during berry ripening is giving evidence that furanoid linalool oxides are generated via two different reaction pathways. Additionally, stereoselective analysis of rose oxide in different varieties that have attained commercial maturity has been performed demonstrating that cis-(2S,4R)-rose oxide is the main stereoisomer in all varieties. (3S)-Hotrienol was the main stereoisomer in all varieties with enantiomeric purities that were always higher than 90%.