Abstract The present study is a first report about of an electrochemical sensor for simultaneous determination of folic acid (FA) and calcium folinate (CF). Also, the work is a first successful application of n-dodecylpyridinium chloride (DPC) as a modifier in simultaneous measurement of folates. This study is based on the adsorption of cationic surfactants at the surface of a carbon paste electrode (CPE) to improve the electrochemical response of the tow analytes. The enhancement effect of DPC is compared with CTAB by differential pulse voltammetry (DPV) technique and DPC shows the better results as a modifier. Other novelty of the work is application of multivariate optimization for optimization of effective parameters in the voltammetric peak current of the analytes. Under the optimized conditions, a peak separation of CF and FA is higher than 270 mV. CPE in the presence of DPC shows wide linear responses for CF and FA in the concentration ranges of 0.1–100.0 µM and 0.05–10.0 µM with detection limits of 24.0 nM and 7.5 nM (3σ), respectively. CPE in the presence of DPC exhibits good repeatability and stability for the two analytes. At the last, CPE in the presence of DPC was successfully applied to the simultaneous detection of FA and CF in urine real samples.

中文翻译：

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基于正十二烷基氯化吡啶增强效应的叶酸和亚叶酸同时测定新方法的多元优化和验证

摘要 本研究首次报道了同时测定叶酸（FA）和亚叶酸钙（CF）的电化学传感器。此外，这项工作是首次成功应用正十二烷基氯化吡啶 (DPC) 作为同时测量叶酸的改性剂。本研究基于在碳糊电极 (CPE) 表面吸附阳离子表面活性剂，以改善两种分析物的电化学响应。通过差分脉冲伏安法（DPV）技术比较了DPC与CTAB的增强效果，DPC作为改性剂显示出更好的效果。这项工作的其他新颖之处是应用多元优化来优化分析物伏安峰值电流中的有效参数。在优化条件下，CF 和 FA 的峰值分离高于 270 mV。DPC 存在下的 CPE 在 0.1–100.0 µM 和 0.05–10.0 µM 的浓度范围内对 CF 和 FA 显示出广泛的线性响应，检测限分别为 24.0 nM 和 7.5 nM (3σ)。在 DPC 存在下，CPE 对两种分析物表现出良好的重复性和稳定性。最后，在DPC存在下的CPE成功地应用于尿液真实样品中FA和CF的同时检测。