石墨烯/纳米二氧化钛/月桂酰-羧甲基壳聚糖电化学传感器对奶粉中痕量锌的测定  

Graphene/Nano-TiO_2/Lauroyl-Carboxymethyl Chitosan Electrochemical Sensor for Determination of Trace Zinc in Milk Powder

作　　者：谭福能 李蕾 TAN Fu-neng;LI Lei(Chemical and Engineering Institute,Wenshan University,Wenshan 663000,Yunnan,China)

机构地区：[1]文山学院化学与工程学院,云南文山663000

出　　处：《食品研究与开发》2018年第8期113-118,共6页Food Research and Development

基　　金：云南省科技厅应用基础研究项目(2012FD058);云南省教育厅科学研究基金项目(2017ZZX056)

摘　　要：将壳聚糖改性成两亲性的月桂酰-羧甲基壳聚糖,并对其结构进行傅里叶变换红外光谱表征。以月桂酰-羧甲基壳聚糖作为原料,与石墨烯(graphene,GR)、纳米二氧化钛制成复合膜修饰玻碳电极(glassy carbon electrode,GCE),制备了一种电化学传感器(GR/TiO_2/LA-CMCS/GCE),研究了锌离子在修饰电极上的电化学行为。通过交流阻抗法(electrochemical impedance spectroscopy,EIS)、循环伏安法(cyclic voltammetry,CV)和线性伏安法(linear sweep voltammetry,LSV)对传感器的电化学特性作了表征,研究了电解质溶液、pH、扫描速度、富集电位和富集时间对锌离子电化学行为的影响。结果表明:锌离子的峰电流与其浓度在2.0×10^(-8) mol/L^4.0×10^(-4) mol/L范围内成良好的线性关系,线性方程为I(μA)=-1.189+0.467 9c(μmol/L),相关系数为0.998 3。该传感器具有良好的重现性、稳定性和抗干扰性,并用此传感器对奶粉样品中痕量锌进行测定,测定结果与火焰原子吸收光谱法结果一致。Lauroyl-carboxymethyl chitosan(LA-CMCS)were prepared by modified of chitosan.The structure of LA-CMCS were characterized by fourier transform infrared spectroscopy.LA-CMCS,graphene(GR)and nano-TiO2 modified glassy carbon electrode as an electrochemical sensor for electrochemical behavior of zinc(II)was studied.The electrochemical performances of modified electrode were investigated by electrochemical impedance spectroscopy,cyclic voltammetry and linear sweep voltammetry.Electrolyte solution,pH,scanning speed,accumulation potential and accumulation time affected electrochemical performances of zinc(II)was investigated.The results showed that peak current increased linearly with increasing zinc(II)concentration in the range of 2.0×10-8 mol/L-4.0×10-4 mol/L,the linear equation was I(μA)=-1.189+0.467 9c(μmol/L),a correlation coefficient was 0.998 3.The electrochemical sensor showed good stability,reproducibility and anti-interference performance.The practical application of the electrochemical sensor was applied for determining the concentration of trace zinc in milk powder samples.The analytical results were no difference between this method and atomic absorption spectrometry.

关 键 词：月桂酰-羧甲基壳聚糖 石墨烯 纳米二氧化钛 修饰电极 锌 

分 类 号：O657.1[理学—分析化学] TS252.51[理学—化学]