Far infrared-assisted extraction followed by capillary electrophoresis for the determination of bioactive constituents in the leaves of Lycium barbarum Linn.

In this work, a method based on capillary electrophoresis with amperometric detection and far infrared-assisted extraction has been developed for the determination of rutin, gentisic acid, and quercetin in the leaves of Lycium barbarum Linn. The effects of detection potential, irradiation time, and the voltage applied on the infrared generator were investigated to acquire the optimum analysis conditions. The detection electrode was a 300-mu m-diameter carbon disc electrode at a detection potential of +0.90 V. The three analytes could be well separated within 12 min in a 40 cm length fused-silica capillary at a separation voltage of 12 kV in a 50 mM borate buffer (pH 9.2). The relation between peak current and analyte concentration was linear over about 3 orders of magnitude with the detection limits (S/N = 3) of 0.31, 0.48, and 0.78 mu M for rutin, gentisic acid, and quercetin, respectively. The proposed method has been applied to determine the three bioactive constituents in real plant samples. (C) 2010 Elsevier B.V. All rights reserved.