AbstractAn electrochemical sensor is described for the simultaneous determination of ortho-hydroxybenzoic acid (OHB) and para-hydroxybenzoic acid (PHB). The sensor consists of a carbon paste electrode modified with nickel titanate nanoceramics (NiTiO3/CPE). The NiTiO3 nanoceramics and the nanostructured modified CPE were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, electrochemical impedance spectroscopy and cyclic voltammetry. Differential pulse voltammetry indicates that the response to OHB (best measured at 0.90 V vs. Ag/AgCl) and PHB (measured at 0.80 V vs. Ag/AgCl) is significantly improved at the modified CPE compared to a bare CPE. The limits of detection (at S/N = 3) are 0.38 and 0.10 μM for OHB and PHB, respectively. The method was applied to the determination of the two isomers in peeling skin lotion and during the Kolbe-Schmitt reaction. Graphical abstractNickel titanate nanoceramics (NiTiO3) were synthesized by a sol-gel method. Then, a carbon paste electrode modified with NiTiO3 (NiTiO3/CPE) was constructed. The modified electrode was applied to the interference-free and simultaneous determination of ortho-hydroxybenzoic acid (OHB) and para-hydroxybenzoic acid (PHB).

中文翻译：

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用钛酸镍纳米陶瓷修饰的碳糊电极，用于同时伏安法测定邻羟基苯甲酸和对羟基苯甲酸

摘要描述了一种用于同时测定邻羟基苯甲酸 (OHB) 和对羟基苯甲酸 (PHB) 的电化学传感器。该传感器由用钛酸镍纳米陶瓷 (NiTiO3/CPE) 改性的碳糊电极组成。NiTiO3纳米陶瓷和纳米结构的改性CPE通过X射线衍射、扫描电子显微镜、透射电子显微镜、电化学阻抗谱和循环伏安法进行了表征。差分脉冲伏安法表明，与裸 CPE 相比，改性 CPE 对 OHB（在 0.90 V 与 Ag/AgCl 下测量最佳）和 PHB（在 0.80 V 与 Ag/AgCl 下测量）的响应显着提高。OHB 和 PHB 的检测限（S/N = 3）分别为 0.38 和 0.10 μM。该方法用于测定去角质润肤露和Kolbe-Schmitt反应过程中的两种异构体。图解摘要采用溶胶-凝胶法合成了钛酸镍纳米陶瓷（NiTiO3）。然后，构建了用 NiTiO3 (NiTiO3/CPE) 改性的碳糊电极。该修饰电极用于无干扰同时测定邻羟基苯甲酸（OHB）和对羟基苯甲酸（PHB）。