Determination of resveratrol in grains, hulls and leaves of common and tartary buckwheat by HPLC with electrochemical detection at carbon paste electrode

Abstract A reverse-phase high-performance liquid chromatographic method for the determination of trans -resveratrol with spectrophotometric detection (306 nm) and amperometric detection at carbon paste electrode ( E  = + 1,2 V) was developed and tested on real samples of grains, hulls and leaves of six varieties of common buckwheat ( Fagopyrum esculentum Moench) and two varieties of tartary buckwheat ( Fagopyrum tataricum (L.) Gaertn.). Optimal conditions for the determination of trans -resveratrol were as follows: column Kromasil C-18 (7 μm), 125 × 4 mm; mobile phase acetonitrile: diluted BR buffer pH 7 (50:50, 30:70 for grains and hulls and 20:80 for leaves); flow rate 1 ml min −1 . Under these conditions, the limit of detection of trans -resveratrol ( L D ) was 3.5 × 10 −8  mol l −1 ( R 2  = 0.9986) for electrochemical detection and 3.2 × 10 −8 mol l −1 ( R 2  = 0.9993) for spectrophotometric detection.