Determination of flavonol glycosides in green tea, oolong tea and black tea by UHPLC compared to HPLC

• Published in: Food chemistry Vol. 183; pp. 30 - 35
• Main Authors: Jiang, Heyuan, Engelhardt, Ulrich H., Thräne, Claudia, Maiwald, Beate, Stark, Janina
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.09.2015
• Subjects: Black tea; Chromatography, High Pressure Liquid - methods; Flavonol glycosides; Flavonols - analysis; Glycosides - analysis; Green tea; HPLC; Oolong tea; Tea - chemistry; UHPLC; M-gal; M-rut; K-rdg; LSYW; Black tea; YNBT; KEBT; Flavonol glycosides; gal; FSOT; K-drglu; K-glu; Q-rdglu; ASBT; UHPLC; Q-gal; Green tea; Q-rut; HPLC; FOG; Q-rrg; M-glu; M-rdg; K-gal; Q-grg; K-grg; SBXT; glu; K-drgal; Q-rgal; Oolong tea; K-rut; WLLJ; DAOT; Q-glu
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2015.03.024

•An UHPLC method to determine flavonol glycosides (FOG) in tea was developed.•Sample clean-up method with polyamide was optimized with multiple-step elutions.•18 FOG compounds in tea were identified and determined with UHPLC and HPLC.•Rutin/kaempferol glucorhamnoglucoside were separated by UHPLC, but HPLC did not.•Most FOG type in tea: green, kaempferol; black, quercetin; oolong, myricetin. 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.