Simultaneous determination of flavones and phenolic acids in the leaves of Ricinus communis Linn. by capillary electrophoresis with amperometric detection

Capillary electrophoresis (CE) with amperometric detection (AD) has been developed for the separation and determination of disaccharide glycoside rutin, gentistic acid, quercetin, and gallic acid in the leaves of Ricinus communis Linn. for the first time. The effects of the acidity and the concentration of the running buffer, separation voltage, injection time, and detection potential were investigated to acquire the optimum conditions for the determination of the four analytes. The detection electrode was a 300 μm diameter carbon disc electrode at a detection potential of +0.90 V (versus saturated calomel electrode (SCE)). The four analytes could be well separated within 10 min in a 40 cm length fused silica capillary at a separation voltage of 15 kV in a 50 mM borate buffer (pH 9.0). The relation between peak current and analyte concentration was linear over about 3 orders of magnitude with detection limits (S/N = 3) ranging from 0.8 to 2.9 μM for all the analytes. The proposed method has been successfully applied to monitor flavones and phenolic acids in the real plant samples with satisfactory assay results.