title: Comparison of nano and conventional liquid chromatographic methods for the separation of (+)-catechin-ethyl-malvidin-3-glucoside diastereoisomers.
abstract: Nano-liquid chromatography and conventional HPLC were used for the separation of diastereomers of (+)-catechin-ethyl-malvidin-3-glucoside. Those bridged anthocyanin dyes were obtained by reaction of (+)-catechin with malvidin-3-glucoside in the presence of acetaldehyde. Both diastereomers were isolated with semipreparative chromatography and their structures were confirmed by nuclear magnetic resonance and mass spectrometry. In-laboratory prepared capillary columns packed with fully porous particles Chromosphere C18, dp=3μm, core-shell particles Kinetex C18, dp=2.6μm (100μm i.d.) and monolithic column Chromolith CapRod (100μm i.d.) were used for the separation of (+)-catechin, malvidin-3-glucoside and both diastereomers. Chromosphere C18 stationary phase provided the best chromatographic performance. Mobile phase containing water:acetonitrile (80:20) acidified with trifluoroacetic acid (0.1%, v/v/v) was used in an isocratic elution mode with a flow rate of 360nLmin(-1). Separation of studied compounds was achieved in less than 7min under optimized conditions. The nano-liquid chromatographic method and a conventional HPLC one using the same fully porous particles (Chromosphere C18, 3μm, 100mm×4.6mm) were compared providing higher separation efficiency with the first analytical method and similar selectivity. A better peak symmetry and higher resolution of the studied diastereomers was achieved by conventional chromatography. Nevertheless, nano-liquid chromatography appeared to be useful for the separation of complex anthocyanin dyes and can be utilized for their analysis in plant and food micro-samples. The developed method was used for analysis of red wine grape pomace.
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Department of Analytical Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 779 00 Olomouc, Czech Republic; Institute of Chemical Methodologies, Italian National Research Council, Area della Ricerca di Roma I, Via Salaria Km 29,300, Monterotondo, 00015 Rome, Italy.
authors.forename: Lukáš
authors.initials: L
authors.lastname: Kučera
authors.affiliation: Institute of Chemical Methodologies, Italian National Research Council, Area della Ricerca di Roma I, Via Salaria Km 29,300, Monterotondo, 00015 Rome, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Fanali
authors.affiliation: Institute of Chemical Methodologies, Italian National Research Council, Area della Ricerca di Roma I, Via Salaria Km 29,300, Monterotondo, 00015 Rome, Italy.
authors.forename: Zeineb
authors.initials: Z
authors.lastname: Aturki
authors.affiliation: Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Chemical Biology and Genetics, Faculty of Science, Palacký University, Šlechtitelů 27, 78371 Olomouc, Czech Republic.
authors.forename: Tomáš
authors.initials: T
authors.lastname: Pospíšil
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Department of Analytical Chemistry, Faculty of Science, Palacký University, 17. listopadu 12, 779 00 Olomouc, Czech Republic. Electronic address: petr.bednar@upol.cz.
authors.forename: Petr
authors.initials: P
authors.lastname: Bednář
mesh_terms: D000079:Acetaldehyde / Q000737:chemistry; D000097:Acetonitriles / Q000737:chemistry; D000872:Anthocyanins / Q000737:chemistry; D002392:Catechin / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D005504:Food Analysis / Q000379:methods*; D005960:Glucosides / Q000737:chemistry; D013058:Mass Spectrometry; D016062:Porosity; D027843:Vitis / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D000872:Anthocyanins; D005960:Glucosides; C458419:malvidin-3-glucoside; D002392:Catechin; D000079:Acetaldehyde; C032159:acetonitrile
keywords: Anthocyanins; Bridged dyes; Capillary column; High-performance liquid chromatography; Nano-liquid chromatography