科研之友
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摘要
A facile and sensitive electrochemical sensor for the determination of flavonoids based on multi-walled carbon paste electrode was fabricated via unique property of cetyltrimethyl ammonium bromide carboxylic multi-walled carbon nanotubes (CTAB-cMWCNTs) composite. Adding CTAB to cMWCNTs is conductive to exert effectively the electro-catalytic property of cMWCNTs, and most importantly, enrich the concentration of flavonoids on the surface of modified electrode to improve the electrochemical performance. Kaempferol (KA) and quercetin (QU) were selected as representative compounds to investigate the electrochemical performance of the modified electrode. Scanning electron microscopy showed that MWCNTs were well mixed with graphite powders in MWCPE on which CTAB-cMWCNTs composite was dispersed uniformly. In comparison with MWCPE and cMWCNTs-modified MWCPE, the modified electrode CTAB-cMWCNTs/MWCPE exhibited higher conductivity and anodic peak currents towards KA and QU, demonstrating that CTAB-cMWCNTs composite exerted a synergistic effect on the electrocatalytic activity of the sensor. Under optimum conditions, the determination range for KA was from 0.02 to 2.0 mu M and from 5.0 to 50.0 mu M, and the linear detection range of QU was from 0.01 to 1.0 mu M and from 2.0 to 20.0 mu M. Moreover, the detection limits of KA and QU were 12.7 nM and 5.3 nM respectively. Finally, the modified electrode was successfully applied to detect KA in Impatiens and dogbane leaf and QU in Rhizome kaempferiae and buds of Styphnolobium japonicum (L.) Schott.
