Abstract Folic acid (FA) acts as an essential nutrient for body functions. Several countries have already proposed a resolution for flour fortification with iron and FA; thus, of food industry concern. Therefore, a new electroanalytical method based on a composite material of functionalized MWCNTs with nickel hydroxide (f-MWCNT-Ni(OH)2) is hereby proposed. This composite material was characterized by FT-IR, TGA, SEM and TEM techniques. An inorganic ionic silsesquioxane polymer (Si4Pic+Cl−) was used to disperse the composite and applied on the modification of a glassy carbon electrode (GCE). Linear response from 0.5–26 μmol L−1 was obtained based on FA electrochemical oxidation through differential pulse voltammetry. The LoD and LoQ values obtained were 0.095 μmol L−1 and 0.3 μmol L−1 of FA, respectively. The GCE/f-MWCNT-Ni(OH)2-Si4Pic+Cl− was applied for the quantification of FA in wheat flour, fortifier, and dietary supplement. Validation was performed through a comparison with molecular absorption spectrometry, showing the accuracy of the newly proposed method.

中文翻译：

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多壁碳纳米管/氢氧化镍复合材料用作食品样品中叶酸（维生素B9）的电化学传感器

摘要 叶酸 (FA) 是维持身体机能的必需营养素。一些国家已经提出了用铁和 FA 强化面粉的决议；因此，受到食品行业的关注。因此，本文提出了一种基于功能化多壁碳纳米管与氢氧化镍 (f-多壁碳纳米管-Ni(OH)2) 复合材料的新电分析方法。这种复合材料通过 FT-IR、TGA、SEM 和 TEM 技术进行了表征。无机离子倍半硅氧烷聚合物（Si4Pic+Cl-）用于分散复合材料并应用于玻璃碳电极（GCE）的改性。基于 FA 电化学氧化通过差分脉冲伏安法获得 0.5-26 μmol L-1 的线性响应。获得的 LoD 和 LoQ 值分别为 0.095 μmol L-1 和 0.3 μmol L-1 的 FA。GCE/f-MWCNT-Ni(OH)2-Si4Pic+Cl− 用于定量小麦粉、强化剂和膳食补充剂中的 FA。通过与分子吸收光谱法的比较进行验证，显示了新提出的方法的准确性。