Department of Analytical Chemistry, Kazan Federal University, Kremleyevskaya 18, 420008 Kazan, Russia.
Sensors (Basel). 2021 Nov 17;21(22):7639. doi: 10.3390/s21227639.
A novel voltammetric sensor based on CeO·FeO nanoparticles (NPs) has been developed for the determination of lipoic acid, playing an essential role in aerobic metabolism in the living organism. Sensor surface modification provides a 5.6-fold increase of the lipoic acid oxidation currents and a 20 mV anodic shift of the oxidation potential. The best voltammetric parameters have been obtained for the 0.5 mg mL dispersion of CeO·FeO NPs. Scanning electron microscopy (SEM) confirms the presence of spherical NPs of 25-60 nm, and their aggregates evenly distributed on the electrode surface and formed porous coverage. This leads to the 4.4-fold increase of the effective surface area vs. bare glassy carbon electrode (GCE). The sensor shows a significantly higher electron transfer rate. Electrooxidation of lipoic acid on CeO·FeO NPs modified GCE is an irreversible diffusion-controlled pH-independent process occurring with the participation of two electrons. The sensor gives a linear response to lipoic acid in the ranges of 0.075-7.5 and 7.5-100 μM with the detection limit of 0.053 μM. The sensor is selective towards lipoic acid in the presence of inorganic ions, ascorbic acid, saccharides, and other S-containing compounds. The sensor developed has been tested on the pharmaceutical dosage forms of lipoic acid.
一种基于 CeO·FeO 纳米粒子 (NPs) 的新型伏安传感器已被开发用于测定硫辛酸，硫辛酸在生物体的需氧代谢中起着重要作用。传感器表面修饰使硫辛酸氧化电流增加了 5.6 倍，氧化电位正向移动了 20 mV。在 CeO·FeO NPs 的 0.5 mg mL 分散体中获得了最佳的伏安参数。扫描电子显微镜 (SEM) 证实了存在 25-60nm 的球形 NPs，其聚集体均匀分布在电极表面上并形成多孔覆盖层。这导致有效表面积相对于裸玻碳电极 (GCE) 增加了 4.4 倍。传感器表现出更高的电子转移速率。CeO·FeO NPs 修饰 GCE 上的硫辛酸电氧化是一个不可逆的扩散控制过程，与两个电子的参与有关。传感器对 0.075-7.5 和 7.5-100 μM 范围内的硫辛酸表现出线性响应，检测限为 0.053 μM。在存在无机离子、抗坏血酸、糖和其他含 S 化合物的情况下，传感器对硫辛酸具有选择性。所开发的传感器已在硫辛酸的药物剂型中进行了测试。
