镍锰氧化物复合电化学传感器对抗坏血酸的检测

Construction of electrochemical sensor and determination of ascorbic acid in food by Ni-Mn oxide composite

摘要:

基于镍锰氧化物复合物对抗坏血酸具有催化氧化作用,因此利用镍锰氧化物复合物修饰玻碳电极构建抗坏血酸快速检测的电化学传感器。通过一步水热合成法制备了镍锰基氧化物复合材料。并利用电子显微镜(SEM)、能量色散X射线能谱(EDS)、X射线衍射(XRD)以及傅里叶红外光谱(FT-IR)对材料的形貌、元素组成以及结构进行表征。结果表明该材料为外表带有孔隙的球型结构,衍射峰索引为Mn2O3(JCPDS编号41-1442)、NiMnO3(JCPDS号48-1330)且Mn-O官能团与Ni-O官能团均存在。采用滴涂法将复合材料修饰于电极表面,用循环伏安法(CV)、差分脉冲伏安法(DPV)测试了抗坏血酸在镍锰氧化物复合物电极上的电化学行为,并对其进行了分析,在pH=4的乙酸缓冲溶液条件下,滴涂量为10μL,抗坏血酸的浓度在0.4～7600 μmol/L时与氧化峰电流值呈线性关系,线性方程为Ip=0.0039 x(mmol/L)+11.643,R2=0.9900,检出限为0.023 μmol/L。该传感器实际应用于果汁饮料中抗坏血酸的含量的测定,加标回收率为95.5%～103.12%,表明它在食品分析等方面具有良好的应用前景。

关键词:抗坏血酸;镍锰氧化物;复合材料;电化学传感器

Abstract:

Based on the catalytic oxidation effect of nickel-manganese oxide complex against corbic acid, an electrochemical sensor for rapid detection of ascorbic acid was constructed by modifying glassy carbon electrode with nickel-manganese oxide complex. Ni - Mn - based oxide composites were prepared by one - step hydrothermal method. Electron microscopy (SEM), EDS, X-ray diffraction (XRD) and Fourier infrared spectroscopy (FT-IR) were used to characterize the morphology, elemental composition ratio and structure of the materials.The structure shows that the material is a spherical structure with voids on the surface. All the diffraction peaks can be indexed as Mn2O3(JCPDS No. 41-1442) ,NiMnO3 (JCPDS No. 48-1330) , and Mn-O and NI-O functional groups exist. According to the response of electric signal, the sensitive and rapid detection of anticorbic acid is realized. The composite material was modified on the electrode surface by drip coating method. The electrochemical behavior of ascorbic acid on the nickel-manganese oxide composite electrode was measured by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Finally, the drop coating amount was determined to be 10μL under the condition of acetic acid buffer solution pH=4. The peak oxidation current of ascorbic acid has a linear relationship with the concentration from 0.4 to 7600 μmol/L. The linear equation is Ip= 0.0039x (mmol/L)+11.643, and the detection limit is 0.023 μmol/L. The sensor has been applied to the determination of ascorbic acid in fruit drinks. The recovery rate of the sensor is 95.5% ~ 103.12%, indicating that it has a good application prospect in food analysis and biochemical analysis.

Key words:Ascorbic acid; nickel manganese oxide; composite materials; electrochemical sensors