石墨烯/四氧化三钴电化学传感器的建立及饼干中香兰素检测分析

Establishment of Graphene/Cobaltosic Oxide Electrochemical Sensorand the Detection and Analysis of Vanillin in Cookies

本文将石墨烯(GR)滴涂在玻碳电极(GCE)后,再通过循环伏安法电聚合氧化Co(COOH)2制得Co3O4/GR/GCE修饰电极作为食品中检测香兰素的新型电化学传感器。通过扫描电镜技术对Co3O4/GR复合纳米材料进行了表征并优化了实验条件。结果表明,当1 mg/mL GR滴涂量为8μL,Co(COOH)2聚合圈数为20圈,0.1 mol/L pH 4.5磷酸缓冲溶液中,香兰素在该传感器下线性关系良好(0.1~80μmol/L),线性方程为:Ip(μmol/L)=0.1518C+0.5103(R2=0.997),检测限为0.033μmol/L(S/N=3)。将此方法应用于饼干样品中香兰素检测,回收率良好,相对标准偏差仅1.47%。综上,该电化学传感器灵敏度较高、稳定性良好,在实际样品检测中具有可行性,拥有广阔的应用前景。

The Co3O4/GR/GCE modified electrode,which as a novel electrochemical sensor for determination of vanillin in food,was prepared by dropping graphene(GR)onto a glassy carbon electrode(GCE)and then electro-polymerized by Co(COOH)2 by cyclic voltammetry in this work.The Co3O4/GR composite nanomaterials were characterized by scanning electron microscopy.Moreover,the experimental conditions were optimized.Results showed that,8.0μL GR solution(1 mg/mL)of coating amount,20 electro-polymerization cycles of Co(COOH)2 and pH=5 of 0.1 mol/L phosphate buffer solution were chosen as the best experimental condition.Therefore,vanillin had a good linear relationship in the concentration range of 0.1~80μmol/L with the electrochemical sensor,and the linear equation was:Ip(μmol/L)=0.1518C+0.5103(R2=0.997)with detection limit was 0.033μmol/L(S/N=3).The method was applied to the determination of vanillin in biscuit samples with good recovery and RSD of 1.47%.The results indicated that the electrochemical sensor had high sensitivity and fabulous stability,which proved the feasibility of the electrochemical sensor in practical sample detection and had a wide application prospect.