| Autor: |
Othman HIA; Centre for Research on Multidimensional Separation Science, School of Chemical Sciences, Universiti Sains Malaysia, Penang 11800, Malaysia., Zaid A; Centre for Research on Multidimensional Separation Science, School of Chemical Sciences, Universiti Sains Malaysia, Penang 11800, Malaysia., Cacciola F; Department of Biomedical, Dental, Morphological and Functional Imaging Sciences, University of Messina, 98125 Messina, Italy., Zhao Z; J&X Technologies (Shanghai) Co., Shanghai 200438, China., Guan X; J&X Technologies (Shanghai) Co., Shanghai 200438, China., Althakafy JT; Department of Chemistry, Faculty of Applied Science, Umm Al-Qura University, Makkah 21955, Saudi Arabia., Wong YF; Centre for Research on Multidimensional Separation Science, School of Chemical Sciences, Universiti Sains Malaysia, Penang 11800, Malaysia. |
| Abstrakt: |
This study evaluates the applicability of enantioselective gas chromatography ( e GC) and enantioselective comprehensive two-dimensional gas chromatography ( e GC×GC) coupled with flame ionization detection for the stereospecific analysis of designated chiral monoterpenes within essential oils distilled from the leaves of Citrus hystrix (CH), C. limon (CL), C. pyriformis (CP), and C. microcarpa (CM). A cryogen-free solid-state modulator with a combination of enantioselective first-dimension and polar second-dimension column arrangements was used to resolve potential interferences in Citrus spp. leaf oils that can complicate the accurate determination of enantiomeric compositions. Interestingly, considerable variations were observed for the enantiomeric fractions (EFs) of the chiral terpenes. (+)-limonene was identified as the predominant enantiomer (60.3-98.9%) in all Citrus oils, (+)-linalool was the major enantiomer in CM (95.9%), (-)-terpenin-4-ol was the major isomer in CM (66.4%) and CP (61.1%), (-)-α-pinene was the dominant antipode in CL (55.5%) and CM (92.1%). CH contained (-)-citronellal (100%) as the pure enantiomer, while CL and CP have lower proportions (9.0-34.6%), and citronellal is absent in CM. The obtained enantiomeric compositions were compared and discussed with results from e GC using the same enantioselective column. To our knowledge, this work encapsulates the first report that details the EFs of these chiral monoterpenes in Citrus spp. leaf oil. |
