Motsaathebe Pholoso Calvin, Fayemi Omolola Ester
Department of Chemistry, Faculty of Natural and Agricultural Sciences, Mafikeng Campus, North-West University, Mmabatho 2735, South Africa.
Material Science Innovation and Modelling (MaSIM) Research Focus Area, Faculty of Natural and Agricultural Sciences, Mafikeng Campus, North-West University, Mmabatho 2735, South Africa.
Nanomaterials (Basel). 2022 Feb 15;12(4):645. doi: 10.3390/nano12040645.
Ascorbic acid (AA) is an essential vitamin in the body, influencing collagen formation, as well as norepinephrine, folic acids, tryptophan, tyrosine, lysine, and neuronal hormone metabolism. This work reports on electrochemical detection of ascorbic acid (AA) in oranges using screen-print carbon electrodes (SPCEs) fabricated with multi-walled carbon nanotube- antimony oxide nanoparticle (MWCNT-AONP) nanocomposite. The nanocomposite-modified electrode displayed enhanced electron transfer and a better electrocatalytic reaction towards AA compared to other fabricated electrodes. The current response at the nanocomposite-modified electrode was four times bigger than the bare electrode. The sensitivity and limit of detection (LOD) at the nanocomposite modified electrode was 0.3663 [AA]/µM and 140 nM, respectively, with linearity from 0.16-0.640 μM and regression value R = 0.985, using square wave voltammetry (SWV) for AA detection. Two well-separated oxidation peaks were observed in a mixed system containing AA and serotonin (5-HT); and the sensitivity and LOD were 0.0224 [AA]/µA, and 5.85 µΜ, respectively, with a concentration range from 23 to 100 µM (R = 0.9969) for AA detection. The proposed sensor outperformed other AA sensors reported in the literature. The fabricated electrode showed great applicability with excellent recoveries ranging from 99 to 107 %, with a mean relative standard deviation (RSD) value of 3.52 % ( = 3) towards detecting AA in fresh oranges.
抗坏血酸（AA）是人体必需的维生素，影响胶原蛋白的形成以及去甲肾上腺素、叶酸、色氨酸、酪氨酸、赖氨酸和神经激素的代谢。本研究报道了使用多壁碳纳米管-氧化锑纳米颗粒（MWCNT-AONP）纳米复合材料制备的丝网印刷碳电极（SPCE）对橙子中的抗坏血酸（AA）进行电化学检测。与其他制备的电极相比，该纳米复合材料修饰电极表现出增强的电子转移和对AA更好的电催化反应。纳米复合材料修饰电极的电流响应比裸电极大四倍。使用方波伏安法（SWV）检测AA时，纳米复合材料修饰电极的灵敏度和检测限（LOD）分别为0.3663 [AA]/μM和140 nM，线性范围为0.16 - 0.640 μM，回归值R = 0.985。在含有AA和血清素（5-HT）的混合体系中观察到两个分离良好的氧化峰；检测AA时，灵敏度和LOD分别为0.0224 [AA]/μA和5.85 μΜ，浓度范围为23至100 μM（R = 0.9969）。所提出的传感器优于文献中报道的其他AA传感器。制备的电极显示出很好的适用性，在检测新鲜橙子中的AA时，回收率高达99%至107%，平均相对标准偏差（RSD）值为3.52%（n = 3）。
