Electropolymerization of thionine (TH) on multiwalled carbon nanotube (MWCNT)–modified glassy carbon electrodes (GCE) in ethaline deep eutectic solvent (DES) was carried out for the first time, to prepare poly(thionine) (PTH) films with different nanostructured morphologies. PTH films were formed on MWCNT/GCE by potential cycling electropolymerization in ethaline with the addition of different acid dopants CH3COOH, HClO4, HNO3, H2SO4 and HCl, acetic acid being the best. The electropolymerization process was monitored with an electrochemical quartz crystal microbalance. The polymerization scan rate was a key factor affecting the electrochemical and morphological properties of the PTHEthaline-CH3COOH/MWCNT/GCE; electrodeposition at 200 mV s−1 showing the best performance. The PTH/MWCNT/GCE platform was characterized using cyclic and differential pulse voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy. The analytical characteristics of the PTH films were evaluated for sensing of ascorbic acid and biosensing of uric acid. The developed sensor exhibited a low detection limit (1.1 μM), wide linear range (2.8–3010 μM) and high sensitivity (1134 μA cm−2 mM−1) for ascorbic acid. After immobilization of uricase, UOx, on PTH/MWCNT/GCE, the biosensor was successfully applied to the determination of uric acid, with fast response (˂ 7 s), good sensitivity (450 μA cm−2 mM−1, wide linear range (0.48–279 μM) and low detection limit (58.9 nM), better than in the literature and than with PTH prepared in aqueous solution. The determination of uric acid in synthetic urine samples was successfully tested and the mean analytical recovery was 100.8 ± 1.4%. This is a promising approach for the determination of uric acid in real samples. Graphical abstract Graphical abstract

中文翻译：

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聚（硫氨酸）-深共熔溶剂/碳纳米管修饰电极的电化学合成和表征及其在电化学传感中的应用

首次在多壁碳纳米管 (MWCNT) 修饰的玻碳电极 (GCE) 上在乙醇深共熔溶剂 (DES) 中电聚合硫氨酸 (TH)，制备具有不同纳米结构的聚 (硫氨酸) (PTH) 薄膜。形态。PTH 薄膜是在 MWCNT/GCE 上通过添加不同酸掺杂剂 CH3COOH、HClO4、HNO3、H2SO4 和 HCl 的电位循环电聚合在乙炔中形成的，醋酸是最好的。电聚合过程用电化学石英晶体微量天平监测。聚合扫描速率是影响PTHEthaline-CH3COOH/MWCNT/GCE电化学和形貌特性的关键因素；在 200 mV s-1 下的电沉积显示出最佳性能。PTH/MWCNT/GCE 平台使用循环和微分脉冲伏安法、电化学阻抗谱和扫描电子显微镜进行表征。评估了 PTH 膜的分析特性，用于抗坏血酸的传感和尿酸的生物传感。开发的传感器对抗坏血酸具有低检测限 (1.1 μM)、宽线性范围 (2.8–3010 μM) 和高灵敏度 (1134 μA cm-2 mM-1)。将尿酸酶 UOx 固定在 PTH/MWCNT/GCE 上后，该生物传感器成功应用于尿酸的测定，响应速度快（˂ 7 s），灵敏度好（450 μA cm−2 mM−1，线性范围宽） (0.48–279 μM) 和低检测限 (58.9 nM)，优于文献中和在水溶液中制备的 PTH。合成尿液样品中尿酸的测定成功进行，平均分析回收率为 100.8 ± 1.4%。这是测定实际样品中尿酸的一种很有前景的方法。图形摘要图形摘要