Since the end of the ’80, cyclodextrin (CD) derivatives have been shown to be highly effective chiral selectors in gas chromatography [1-3]. Many applications of enantioselective GC (ES-GC) with cyclodextrins as stationary phases are from the field of flavour and fragrance [4-6] where the enantiomeric excess (EE) and/or ratio (ER) determination is a very important task to define not only the biosynthetic pathway or the origin of a compound, but also to evaluate the authenticity of a sample or to detect frauds. Recent studies [7] overcome the main limit of ES-GC analyses for routine application, i.e. the long analysis time, by short and narrow bore columns looking for the best compromise between analysis time gain and loss of resolution. The limiting condition to enable a correct EE and ER determination is a resolution of at least 1.5 for the investigated enantiomers. Several successful 6-tert-butyldimethylsilyl cyclodextrin derivatives with the same substituent (symmetrically substituted CDs) in position 2 and 3 were synthesized as stationary phases for ES-GC analyses. However, the development of new CD derivatives is still necessary to improve their separation capacity and/or specificity and to speed-up ES-GC analyses for the routine Q.C. This study is part of a project aiming to develop new CD derivatives with different apolar and polar substituents in position 2 and 3 (asymmetrically substituted CDs), i.e. 2-O-ethyl-3-O-methyl-6-O-tBDMS- β-CD (EM), 2-O-methyl-3-O-ethyl-6-O-tBDMS-β-CD (ME) and 2-O-methyl-3-O-acetyl-6-O-tBDMS-β-CD (MA) to increase both the number of separated chiral compounds and their resolution. More than a hundred standard racemates of chiral molecules from the flavour and fragrance field and a set of real-world samples were analysed with the new derivatives and their performance was compared to that of the corresponding symmetrically substituted CDs (i.e. 2,3-di-O-ethyl-6-O-tBDMS-β-CD [8] and 2,3-di-O-methyl-6-O-tBDMS-β-CD [9], 2,3-di-O-acetyl-6-O-tBDMS-β-CD [9]). The new derivatives showed good chromatographic properties and enantioselectivity providing the MEand EM-CDs an higher separation capability while the MA-CD higher specificity for carbonyl compounds; they are therefore suitable to be explored to speeding-up ES-GC.

New Cyclodextrin Derivatives to improve capacity, specificity and speed of essential oil ES-GC analyses

CAGLIERO, Cecilia Lucia;BICCHI, Carlo;SGORBINI, Barbara;CRAVOTTO, Giancarlo;RUBIOLO, Patrizia;LIBERTO, Erica
2009-01-01

Abstract

Since the end of the ’80, cyclodextrin (CD) derivatives have been shown to be highly effective chiral selectors in gas chromatography [1-3]. Many applications of enantioselective GC (ES-GC) with cyclodextrins as stationary phases are from the field of flavour and fragrance [4-6] where the enantiomeric excess (EE) and/or ratio (ER) determination is a very important task to define not only the biosynthetic pathway or the origin of a compound, but also to evaluate the authenticity of a sample or to detect frauds. Recent studies [7] overcome the main limit of ES-GC analyses for routine application, i.e. the long analysis time, by short and narrow bore columns looking for the best compromise between analysis time gain and loss of resolution. The limiting condition to enable a correct EE and ER determination is a resolution of at least 1.5 for the investigated enantiomers. Several successful 6-tert-butyldimethylsilyl cyclodextrin derivatives with the same substituent (symmetrically substituted CDs) in position 2 and 3 were synthesized as stationary phases for ES-GC analyses. However, the development of new CD derivatives is still necessary to improve their separation capacity and/or specificity and to speed-up ES-GC analyses for the routine Q.C. This study is part of a project aiming to develop new CD derivatives with different apolar and polar substituents in position 2 and 3 (asymmetrically substituted CDs), i.e. 2-O-ethyl-3-O-methyl-6-O-tBDMS- β-CD (EM), 2-O-methyl-3-O-ethyl-6-O-tBDMS-β-CD (ME) and 2-O-methyl-3-O-acetyl-6-O-tBDMS-β-CD (MA) to increase both the number of separated chiral compounds and their resolution. More than a hundred standard racemates of chiral molecules from the flavour and fragrance field and a set of real-world samples were analysed with the new derivatives and their performance was compared to that of the corresponding symmetrically substituted CDs (i.e. 2,3-di-O-ethyl-6-O-tBDMS-β-CD [8] and 2,3-di-O-methyl-6-O-tBDMS-β-CD [9], 2,3-di-O-acetyl-6-O-tBDMS-β-CD [9]). The new derivatives showed good chromatographic properties and enantioselectivity providing the MEand EM-CDs an higher separation capability while the MA-CD higher specificity for carbonyl compounds; they are therefore suitable to be explored to speeding-up ES-GC.
2009
40th International Symposium on Essential Oils
Savigliano
6-9 settembre 2009
40th International Symposium on Essential Oils
Bicchi and Rubiolo
45
45
http://www.iseo2009.unito.it/
Cecilia Cagliero; Carlo Bicchi; Chiara Cordero; Barbara Sgorbini; Giancarlo Cravotto; Patrizia Rubiolo; Erica Liberto
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/63910
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