Rapid Analysis of 18 Flavonoids in Tea by Ultrahigh-Performance Liquid Chromatography Coupled with Quadrupole-Time of Flight Mass Spectrometry

A method was established for the determination of 18 flavonoids in tea by ultra-performance liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (UPLC-Q-TOF/MS). The tea samples were extracted by 70% (V/V) methanol aqueous solution, and separation was achieved on a Kinetex F5 column (2.1 mm x 100 mm, 2.6 & mu;m) with methanol and 0.1% formic acid in water as the mobile phase with a gradient elution. The samples were detected in TOF/MS and information-dependent acquisition (IDA)-MS/MS modes. The results showed that the relative standard deviations of 18 flavonoids were less than 5.0 ppm. The correlation coefficients (R-2) of the linear equation were greater than 0.998 in the range of 0.10-200 ng/mL. The limits of detection were 0.0010-0.040 ppm, and the limits of quantification were 0.0020-0.10 ppm. The recoveries ranged from 73.8% to 107% at spiked levels of 0.0020-1.0 ppm, with relative standard deviations (RSDs) being less than 10%. The method was simple, specific, and reliable. It could be used for the rapid screening and quantitative analysis of flavonoids in tea.