title: Determination of flavonol glycosides in green tea, oolong tea and black tea by UHPLC compared to HPLC.
abstract: An UHPLC method for the determination of flavonol glycosides (FOG) from green and oolong tea vs. black tea has been developed for the first time. Sample clean-up method by means of polyamide column chromatography was optimized with multiple-step elution. Using UHPLC and HPLC with gradient elution and photodiode array detection, eighteen FOG compounds were determined with the aid of electrospray tandem mass spectrometry. These FOG compounds were qualified on both UHPLC and HPLC, and this UHPLC method successfully separated rutin (quercetin-3-O-rutinoside) and K-grg (kaempferol-3-O-glucorhamnoglucoside) while conventional HPLC method did not. The total amounts of FOG compounds in the tea samples were 2.32-5.67g/kg dry weight (calculated as aglycones), and there is no significant difference for the total FOG content among green tea, oolong tea and black tea. However, kaempferol glycosides are more abundant in green teas, while oolong tea has more quercetin and myricetin glycosides. In black tea quercetin glycosides were most abundant.
authors: Key Laboratory of Tea Biology and Resource Utilization of Ministry of Agriculture, Tea Research Institute, Chinese Academy of Agricultural Sciences, 9 South Meiling Road, Hangzhou 310008, China; Institute of Food Chemistry, Technische Universität Braunschweig, Schleinitzstrasse 20, D-38106 Braunschweig, Germany; Key Laboratory of Tea Processing Engineering of Zhejiang Province, 9 South Meiling Road, Hangzhou 310008, China.
authors: Heyuan
authors: H
authors: Jiang
authors: Institute of Food Chemistry, Technische Universität Braunschweig, Schleinitzstrasse 20, D-38106 Braunschweig, Germany. Electronic address: u.engelhardt@tu-braunschweig.de.
authors: Ulrich H
authors: UH
authors: Engelhardt
authors: Institute of Food Chemistry, Technische Universität Braunschweig, Schleinitzstrasse 20, D-38106 Braunschweig, Germany.
authors: Claudia
authors: C
authors: Thräne
authors: Institute of Food Chemistry, Technische Universität Braunschweig, Schleinitzstrasse 20, D-38106 Braunschweig, Germany.
authors: Beate
authors: B
authors: Maiwald
authors: Institute of Food Chemistry, Technische Universität Braunschweig, Schleinitzstrasse 20, D-38106 Braunschweig, Germany.
authors: Janina
authors: J
authors: Stark
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D044948:Flavonols / Q000032:analysis*; D006027:Glycosides / Q000032:analysis*; D013662:Tea / Q000737:chemistry*
chemical_list: D044948:Flavonols; D006027:Glycosides; D013662:Tea
keywords: Black tea; Flavonol glycosides; Green tea; HPLC; Oolong tea; UHPLC