title: Comprehensive two-dimensional liquid chromatographic analysis of anthocyanins.
abstract: Anthocyanins are naturally occurring plant pigments whose accurate analysis is hampered by their complexity and unique chromatographic behaviour associated with on-column conversion reactions. This paper reports the evaluation of off-line comprehensive two-dimensional liquid chromatography (LC×LC) for the analysis of anthocyanins. Hydrophilic interaction chromatography (HILIC) was used in the first dimension in combination with reversed phase liquid chromatography (RP-LC) in the second dimension. For the selective detection of anthocyanins, diode array detection was used, while high resolution quadrupole-time-of-flight mass spectrometry (Q-TOF) was used for compound identification. As application, the HILIC×RP-LC separation of diverse anthocyanins in blueberries, red radish, black beans, red grape skins and red cabbage is demonstrated. Off-line HILIC×RP-LC revealed information which could not be obtained by one-dimensional HPLC methods, while the structured elution order for the anthocyanins simplifies compound identification and facilitates the comparison of anthocyanin content of natural products by means of contour plots.
authors.affiliation: Stellenbosch University, Department of Chemistry and Polymer Science, Private Bag X1, Matieland 7602, South Africa.
authors.forename: Chandré M
authors.initials: CM
authors.lastname: Willemse
authors.affiliation: Stellenbosch University, Central Analytical Facility, Private Bag X1, Matieland 7602, South Africa; Stellenbosch University, Department of Biochemistry, Private Bag X1, Matieland 7602, South Africa.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Stander
authors.affiliation: Stellenbosch University, Department of Chemistry and Polymer Science, Private Bag X1, Matieland 7602, South Africa.
authors.forename: Andreas G J
authors.initials: AG
authors.lastname: Tredoux
authors.affiliation: Stellenbosch University, Department of Chemistry and Polymer Science, Private Bag X1, Matieland 7602, South Africa. Electronic address: ajdevill@sun.ac.za.
authors.forename: André
authors.initials: A
authors.lastname: de Villiers
mesh_terms: D000872:Anthocyanins / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002853:Chromatography, Liquid / Q000379:methods*; D005638:Fruit / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D013058:Mass Spectrometry; D010936:Plant Extracts / Q000737:chemistry*; D027843:Vitis / Q000737:chemistry*
chemical_list: D000872:Anthocyanins; D010936:Plant Extracts
keywords: Anthocyanins; Comprehensive two-dimensional liquid chromatography (LC×LC); Hydrophilic interaction chromatography (HILIC); Orthogonality; Phenolic compounds; Reversed phase liquid chromatography (RP-LC)