3种黄酮化合物在PLGA/GCE上的微分脉冲伏安测定

目的: 实现低浓度范围的三种母体结构相同天然黄酮化合物的电化学同时测定。 方法: 在聚合谷氨酸薄膜修饰玻碳电极(PLGA/GCE)上,采用电化学微分脉冲伏安技术(DPV)测定3种化合物的氧化峰,扫描的电位区间为-0.2~+0.6 V,电势增量0.0010 V,脉冲幅度0.0600 s,富集电位0.4 V,富集时间120 s。 结果: 在10^-7~10^-6 mol· L^-1 浓度范围,3种化合物氧化峰电流与浓度成线性关系,电极稳定,连续测定不会造成电极表面阻抗没有明显增大,且能实现3种化合物在低浓度的同时测定,在化合物浓度低至5.0×10^-7mol· L^-1 时,槲皮素,山柰酚和木犀草素3种化合物的氧化峰分别位于-0.016,0.085 和0.160 V,不发生重叠,峰电流与浓度仍保持良好的线性关系,检测限低至2.149×10^-7 mol· L^-1 (山柰酚)。 结论: 该方法操作简单,检测限低,灵敏度高,有望广泛应用于类似结构黄酮化合物的同时测定。

Objective: To develop the sensitive electrochemical method for three flavonoids simultaneous determination. Methods: A conductive polymer film-poly(L-glutamic acid)(PLGA)was electropolymerized on the glassy carbon electrode (GCE)for the electrocatalytic oxidation of flavonoids in aqueous solutions.Differential pulse voltammetric (DPV)method was used to investigate the electrochemical oxidation of flavonoids on PLGA/GCE.DPV conditions:scans range,from-0.2 to +0.6 V; pulse amplitude,0.0010 mV; pulse width,0.0600s. Results: The peak currents for flavonoids increased linearly with an increase concentration in the range of 10^-7–10^-6 M.No obvious change was observed after continuous DPV scans.The DPV results showed that the simultaneous determination of quercetin,kaempferol and kuteolin at PLGA/GCE was possible when their concentration as lower as 5.0×10^-7 mol·L^-1,with three well-defined anodic peaks at potentials of-0.016,0.085 and 0.160 V,corresponding to the oxidation of quercetin,kaempferol and kuteolin,respectively. Conclusions: The method is simple and accurate with good reproducibility,and can be used for the highly selective determination of flavonoids.As the electrode fabrication is very easy and low cost,the present modified electrode seems to be of great utility for making a electrochemical sensor for the simultaneous detection of quercetin,kaempferol and kuteolin.