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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 achieve the simultaneous electrochemical determination of the same natural flavonoids in three kinds of maternal structures with low concentration range. Methods: Oxidation peaks of three compounds were determined by electrochemical differential pulse voltammetry (DPV) on polyglutamic acid (MWCNT) modified glassy carbon electrode (PLGA / GCE) with the potential range of -0.2 ~ +0.6 V, The potential increment is 0.0010 V, the pulse amplitude is 0.0600 s, the enrichment potential is 0.4 V, and the enrichment time is 120 s. Results: In the range of 10-7 ~ 10-6 mol·L-1, the oxidation peak currents of the three compounds were in a linear relationship with the concentration, and the electrodes were stable. The continuous measurement did not cause no significant increase of the electrode surface resistance and could achieve 3 The oxidation peak of quercetin, kaempferol and luteolin at the compound concentration as low as 5.0 × 10-7mol·L-1 were located at -0.016, 0.085 and 0.160, respectively V, no overlap, the peak current and concentration still maintained a good linear relationship with the detection limit as low as 2.149 × 10-7 mol.L-1 (kaempferol). Conclusion: The method is simple, low detection limit, high sensitivity and is expected to be widely used in the simultaneous determination of flavonoids with similar structure.