Abstract In this work, we report a novel, cost effective and environmental-friendly green synthesis method of reduced graphene oxide (rGO) – tin oxide (SnO2) composite using lemon extract by hydrothermal process for selective and ultra-sensitive electrochemical detection of ascorbic acid. The electrochemical behavior of ascorbic acid at the surface of rGO-SnO2 composite modified glassy carbon electrode (GCE) was investigated by cyclic voltammetry (CV) technique whilst ascorbic acid sensing was performed by using differential pulse voltammetry (DPV) technique. An excellent sensitivity of 1200 μA mM−1 cm−2 (R2 = 0.990) towards ascorbic acid in the wide dynamic range of 400 μM −1600 μM without any surface fouling effect was observed which is, to the best of our knowledge, ~1.6 folds higher than previously reported ascorbic acid sensors. The as-fabricated sensor exhibited lower limit of detection (38.7 μM), superior reproducibility and selectivity towards interfering species such as glucose, urea, uric acid and Na+ ions. This enhanced sensing ability was studied and discussed in terms of forward biased nano-Schottky barriers at the rGO-SnO2 interface. The sensor was successfully evaluated for the detection of ascorbic acid in the vitamin C tablets and to predict unknown concentrations of ascorbic acid in PBS solution. This ultrasensitive, binder free rGO–SnO2 composite based sensor can be used for a simple, low cost and voltammetric detection of ascorbic acid in clinical diagnostics, pharmaceutical and food industries.

中文翻译：

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用于高选择性和超灵敏检测抗坏血酸的还原氧化石墨烯/氧化锡复合材料的简便绿色合成

摘要 在这项工作中，我们报告了一种新颖、经济且环保的还原氧化石墨烯 (rGO)-氧化锡 (SnO2) 复合材料的绿色合成方法，该方法使用柠檬提取物通过水热法选择性和超灵敏电化学检测抗坏血酸. 通过循环伏安法 (CV) 技术研究了抗坏血酸在 rGO-SnO2 复合改性玻碳电极 (GCE) 表面的电化学行为，同时使用差分脉冲伏安法 (DPV) 技术进行了抗坏血酸传感。观察到在 400 μM -1600 μM 的宽动态范围内对抗坏血酸具有 1200 μA mM-1 cm-2 (R2 = 0.990) 的出色灵敏度，没有任何表面污染效应，据我们所知，约为 1.6倍数高于先前报道的抗坏血酸传感器。制造的传感器表现出检测下限 (38.7 μM)、出色的重现性和对干扰物质（如葡萄糖、尿素、尿酸和 Na+ 离子）的选择性。在 rGO-SnO2 界面处的正向偏置纳米肖特基势垒方面研究和讨论了这种增强的传感能力。该传感器已成功用于检测维生素 C 片剂中的抗坏血酸并预测 PBS 溶液中未知浓度的抗坏血酸。这种基于超灵敏、无粘合剂 rGO-SnO2 复合材料的传感器可用于临床诊断、制药和食品行业中抗坏血酸的简单、低成本和伏安检测。尿酸和钠离子。在 rGO-SnO2 界面处的正向偏置纳米肖特基势垒方面研究和讨论了这种增强的传感能力。该传感器已成功用于检测维生素 C 片剂中的抗坏血酸并预测 PBS 溶液中未知浓度的抗坏血酸。这种基于超灵敏、无粘合剂 rGO-SnO2 复合材料的传感器可用于临床诊断、制药和食品行业中抗坏血酸的简单、低成本和伏安检测。尿酸和钠离子。在 rGO-SnO2 界面处的正向偏置纳米肖特基势垒方面研究和讨论了这种增强的传感能力。该传感器已成功用于检测维生素 C 片剂中的抗坏血酸并预测 PBS 溶液中未知浓度的抗坏血酸。这种超灵敏、无粘合剂的 rGO-SnO2 复合传感器可用于临床诊断、制药和食品行业中抗坏血酸的简单、低成本和伏安检测。