Abstract Glassy carbon electrode modified with multi-walled carbon nanotubes and electropolymerized gallic acid (poly(gallic acid)/MWNT/GCE) has been developed for the direct quercetin quantification. The potentiodynamic electropolymerization procedure has been optimized. The best quercetin response has been registered on the polymeric film obtained using 15 cycles from 10 μM gallic acid in phosphate buffer (PB) pH 6.0 in the potential range from − 0.2 to 1.0 V and the scan rate of 100 mV s− 1. Scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) has been applied for the electrode characterization. The polymeric film has porous structure providing high surface area in comparison to GCE (26.1 ± 4.1 vs. 3.14 mm2, respectively) as well as gives 1.7-fold decrease of the charge transfer resistance. The poly(gallic acid)/MWNT/GCE response is linear in the ranges of 0.075–25 μM and 25–100 μM of quercetin with the detection limit of 54 nM. The electrode selectivity in the presence of structurally related phenolic compounds is found. The method developed has been successfully applied for the medicinal herbs extract analysis. A good agreement with the independent determination has been obtained.

中文翻译：

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聚（没食子酸）/MWNT 修饰电极用于选择性和灵敏地伏安法测定药材中槲皮素

摘要 用多壁碳纳米管和电聚合没食子酸（聚（没食子酸）/MWNT/GCE）修饰的玻碳电极已被开发用于直接定量槲皮素。动电位电聚合过程已经过优化。使用 10 μM 没食子酸磷酸盐缓冲液 (PB) pH 6.0 在 − 0.2 到 1.0 V 的电位范围和 100 mV s− 1 的扫描速率下，使用 15 个循环获得的聚合物膜上记录了最佳槲皮素响应。 扫描电子显微镜 (SEM)、循环伏安法 (CV) 和电化学阻抗谱 (EIS) 已用于电极表征。聚合物薄膜具有多孔结构，与 GCE 相比提供了高表面积（分别为 26.1 ± 4.1 和 3.14 mm2），并且电荷转移电阻降低了 1.7 倍。聚（没食子酸）/MWNT/GCE 响应在 0.075-25 μM 和 25-100 μM 槲皮素范围内呈线性，检测限为 54 nM。发现存在结构相关的酚类化合物时的电极选择性。所开发的方法已成功应用于药材提取物的分析。已获得与独立决定的良好一致。