Enantioselective Gas Chromatography with Cyclodextrin in Odorant Analysis

Abstract

This chapter concerns enantioselective gas chromatography with cyclodextrin derivatives as chiral stationary phases for chiral recognition of volatile odorants in the flavour and fragrance field. The text is divided into two main parts. The first one is more general and deals with enantiomers and odour and need for chiral recognition, evolution of chiral stationary phases for enantioselective GC since its beginning, followed by the history of cyclodextrins and their applications to enantioselective GC. It also includes some theoretical aspects of enantiomer separation with cyclodextrin derivatives and their influence on routine chiral recognition.The second part concerns the strategy of chiral recognition in routine analysis with cyclodextrin derivatives as chiral stationary phases illustrated by examples with real natural product samples. This part describes enantiomer automatic identification or their excess or ratio determination in complex mixtures by enantioselective GC combined with mass spectrometry; in particular it deals with the potential of multidimensional techniques and of fast GC in chiral recognition and the role played by mass spectrometry. The last paragraph concerns the use of total analysis systems in chiral recognition.

Corylus avellana L. Natural Signature: Chiral Recognition of Selected Informative Components in the Volatilome of High-Quality Hazelnuts

“…Supplementary Table 1 lists targeted analytes putatively identified in raw and roasted samples on the MeAc-TBDM-β-CD column, together with their experimental I T and targeted ion ( m/z ) adopted for profiling purposes. The identification was by spectral similarity match above 95% (Agilent PBM algorithm) estimated over commercial and in-house databases, and I T comparison with the in-house database of retention indexes when available ( Liberto et al, 2008 ; Cagliero et al, 2017 ). Additional information on spectral data and I T s standard stationary phases can be retrieved in Supplementary Table 3 where chemical formulae and National Institute of Standard and Technology (NIST) database links are provided.…”

“…In addition, it is important to consider that the biosynthesis of some key odorants is very often stereo-guided and usually results in chiral components with a more or less marked enantiomeric excess. At the same time, the interaction of the odorants with olfactory receptors is mainly stereoselective, meaning that the enantiomers of a chiral molecule might present different organoleptic properties while eliciting different odor sensations and/or intensities ( Koppenhoefer et al, 1994 ; Brenna et al, 2003 ; Cagliero et al, 2017 ).…”

Comprehensive Instrumental Odor Analysis Using SIFT-MS: A Case Study

“…These range from instrument-based techniques like gas chromatography mass spectrometry (GC/MS) where the odor molecules are separated in a chromatographic column before detection [6] to olfactory techniques which allow human evaluators [7,8] to sensor-based technologies embracing a wide range of different detectors [9][10][11]. Conventional sensor-based and chromatographic techniques are not well suited to the task of monitoring odors due to the rapidly changing and variable nature of the emissions [12][13][14][15][16]. New direct technologies without chromatography are now being applied to odor monitoring and one of these techniques, selected ion flow tube mass spectrometry (SIFT-MS) [17][18][19][20] is presented here.…”

Enantioselective HS-SPME-GC-MS for Authentication of Natural and Synthetic Strawberry Flavour in Syrups

“…The condition for such a determination was to find a chiral column allowing good separation of the enantiomers of the investigated substances. Modified forms of cyclodextrin are gaining in popularity as the bases of chiral stationary phases in GC enabling enantiomeric separation of almost all classes of volatile chiral compounds, highly effective in the flavour and fragrance field [Betzenbitcher et al, 2022;Cagliero et al, 2015Cagliero et al, , 2017Engel, 2020]. For a specific case -a molecule of permethylated β-cyclodextrin separating enantiomers of selected flavours in GC -Lipkowitz's group described a lot of aspects of the separation mechanisms [Lipkowitz et al, 1997a,b;1998].…”

“…Therefore, testing the functionality of chiral selectors by their direct application in the chromatographic analysis of real samples is a significant support in the field of enantioselectivity research. The CP-Chirasil-Dex CB column was chosen for our investigation due to its possible efficiency in separating enantiomers of the investigated enantiomeric pairs, due to the popularity of similar enantioseparating columns in relevant literature [Betzenbichler et al, 2022;Cagliero et al, 2017;de la Peňa Moreno et al, 2010;Schmalzing et al, 1992], as well as because of the results achieved on β-cyclodextrin phases in the analysis of strawberries (Table 1).…”