Comprehensive two-dimensional liquid chromatographic analysis of rooibos (Aspalathus linearis) phenolics
Date
2012
Authors
Beelders T.
Kalili K.M.
Joubert E.
De Beer D.
De Villiers A.
Journal Title
Journal ISSN
Volume Title
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Abstract
Rooibos tea is an unique beverage prepared from unfermented and fermented plant material of the endemic Cape fynbos plant, Aspalathus linearis. The well-known health-promoting benefits of rooibos are partly attributed to its phenolic composition. Detailed investigation of the minor phenolic constituents of rooibos is, however, hampered by the limitations associated with conventional HPLC methods used for its analysis. In this study, the applicability of comprehensive two-dimensional liquid chromatographic methods for the in-depth analysis of rooibos phenolics was investigated. Phenolic compounds were separated according to polarity by hydrophilic interaction chromatography (HILIC) in the first dimension, whilst reversed-phase liquid chromatography (RP-LC) provided separation according to hydrophobicity in the second dimension. Ultraviolet photodiode array and electrospray ionisation mass spectrometry were used to identify phenolic compounds. Comprehensive HILIC × RP-LC demonstrated its applicability for the analysis of a diverse range of phenolic compounds in unfermented and fermented rooibos samples, in which large qualitative differences in the phenolic composition were established. The combination of these orthogonal separations provided a significant improvement in resolution, as exemplified by practical peak capacities in excess of 2000 and 500 for off-line and on-line methods, respectively. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Description
Article
Keywords
Comprehensive two-dimensional liquid chromatography (LC × LC), Hydrophilic interaction chromatography (HILIC), Mass spectrometry, Phenolic compounds, Rooibos
Citation
Journal of Separation Science
35
14
1808
1820
35
14
1808
1820