Abstract A new method for the determination of dopamine (DA) and paracetamol (PCT), based on the azo “coupling reaction with oxidized 2,4-dinitrophenylhydrazine (DNPH), has been established. This method was based on the fact that in the HCl buffer solution, potassium ioadate oxidized 2,4-dinitrophenylhydrazine to form the diazonium chloride at 0–5 °C and then the diazonium ion reacted with the phenolic compounds to form azo-compounds. The products of the azo coupling reaction were characterized by UV/Vis spectrophotometry, infrared spectroscopy and square wave voltammetry. Using a MeOH/Water buffer solution (pH 9.0) and electrochemical impedance spectroscopy, DA and PCT were determined in the concentration range of 0.1–1000 μmol L−1, with limits of detection of 0.47 and 0.25 μmol L−1, respectively. The proposed method was successfully applied to the individual determination of DA and PCT in various pharmaceutical formulas, showing the practical feasibility of the proposed method as a novel platform for the sensitive determination of these phenolic compounds.

中文翻译：

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使用偶氮偶联反应与氧化 2,4-二硝基苯肼 (DNPH) 的电化学阻抗谱间接测定多巴胺和扑热息痛：在商业片剂中的应用

摘要 建立了一种基于偶氮“与氧化2,4-二硝基苯肼（DNPH）偶联反应”测定多巴胺（DA）和扑热息痛（PCT）的新方法。该方法基于以下事实：在 HCl 缓冲溶液中，碘酸钾在 0-5°C 氧化 2,4-二硝基苯肼形成重氮氯化物，然后重氮离子与酚类化合物反应形成偶氮化合物。偶氮偶联反应产物用紫外/可见分光光度法、红外光谱法和方波伏安法表征。使用甲醇/水缓冲溶液 (pH 9.0) 和电化学阻抗谱，在 0.1–1000 μmol L-1 的浓度范围内测定 DA 和 PCT，检测限分别为 0.47 和 0.25 μmol L-1。