Comprehensive two-dimensional liquid chromatographic analysis of rooibos (Aspalathus linearis) phenolics

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dc.contributor.authorBeelders T.
dc.contributor.authorKalili K.M.
dc.contributor.authorJoubert E.
dc.contributor.authorDe Beer D.
dc.contributor.authorDe Villiers A.
dc.date.accessioned2012-08-13T07:45:43Z
dc.date.available2012-08-13T07:45:43Z
dc.date.issued2012
dc.descriptionArticle
dc.description.abstractRooibos 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.
dc.identifier.citationJournal of Separation Science
dc.identifier.citation35
dc.identifier.citation14
dc.identifier.citation1808
dc.identifier.citation1820
dc.identifier.issn16159306
dc.identifier.otherdoi:10.1002/jssc.201200060
dc.identifier.urihttp://hdl.handle.net/10019.1/49194
dc.subjectComprehensive two-dimensional liquid chromatography (LC × LC)
dc.subjectHydrophilic interaction chromatography (HILIC)
dc.subjectMass spectrometry
dc.subjectPhenolic compounds
dc.subjectRooibos
dc.titleComprehensive two-dimensional liquid chromatographic analysis of rooibos (Aspalathus linearis) phenolics
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