Determination of Rutin in Buckwheat Tea and Fagopyrum tataricum Seeds by High Performance Liquid Chromatography and Capillary Electrophoresis

Simple, fast and very sensitive high performance liquid chromatography (HPLC) and capillary electrophoresis (CE) methods for the determination of rutin were developed. The separation of rutin by HPLC was performed using a Chromolith RP 18 column with detection wavelength at 356 nm. Composition of mobile phase was methanol : water (50 : 50, v/v) in 10 mM acetate buffer at pH 4.1. The limit of detection (at a signal-to-noise ratio of 3) was 23.91 ng/mL. Relative standard deviations of retention time, peak area and peak height (n = 5) for rutin were 0.199, 0.832 and 0.522 %. respectively. For CE method, rutin was seperated on a bare fused silica column. Borate buffer at pH 9.4 was used as the background electrolyte and detected wavelength was 208 nm. The limit of detection (at a signal-to-noise ratio of 3) was 55.67 ng/mL by using a 5 s injection time and +20 kV power supply. Relative standard deviations of retention time, peak area and peak height (n = 5) were 0.377, 0.923 and 2.446%, respectively. Both methods were applied to determine rutin in buckwheat tea and Fagopyrum tataricum seeds. Sample matrix in buckwheat tea was removed by using Sep-Pak C18 prior injection to HPLC and CE. The results for rutin determination obtained by the HPLC method agreed well with those from CE method.