亚硝酸根和L-色氨酸在多壁碳纳米管、氧化石墨烯和羧甲基壳聚糖修饰的玻碳电极上的电化学行为及其含量测定  

Electrochemical Behaviors and Determination of NO_2^- and L-Tryptophan at Multi-Walled Carbon Nanotubes,Graphene Oxide,Carboxymethyl Chitosan Modified Glassy Carbon Electrode

作　　者：张军丽 张佳欣 张宁 策萌萌 ZHANG Junli;ZHANG Jiaxin;ZHANG Ning;CE Mengmeng(College of Chemical and Pharmaceutical Engineering, tYuanghuai University, Zhumadian 463000, Chin)

机构地区：[1]黄淮学院化学与制药工程学院,驻马店463000

出　　处：《理化检验（化学分册）》2018年第6期708-713,共6页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

基　　金：河南省科技发展计划项目(182102311057;132300410312);驻马店市科技发展计划项目(13604);黄淮学院青年骨干教师资助计划项目;2017年河南省高等教育教学改革研究与实践项目(2017SJGLX459)

摘　　要：将氧化石墨烯(GO)、多壁碳纳米管(MWNTs)和羧甲基壳聚糖(CMCS)超声混合后滴涂到玻碳电极(GCE)基体上得到修饰电极(MWNTs/GO/CMCS/GCE),采用循环伏安法(CV)考察NO2-和L-色氨酸(L-Trp)在修饰电极上的电化学行为。计算得MWNTs/GO/CMCS/GCE的有效面积为3.243 0×10-6cm2,电极膜表面积明显增加,加速了电子转移,有利于被测物质的吸附和富集。结果表明:NO2-(在pH 4.7磷酸盐缓冲溶液中)和L-Trp(在pH 4.0乙酸-乙酸钠缓冲溶液中)在该修饰电极上分别有明显的电催化氧化作用;两者的浓度依次在1.0×10-7~3.5×10-1 mol·L-1和1.0×10-8~2.7×10-1 mol·L-1内与其相应的氧化峰电流值之间呈线性关系,其检出限(3S/N)依次为1.2×10-8,5.0×10-8 mol·L-1。方法用于腐败生菜中NO2-含量和模拟样品中L-Trp含量的CV测定,所得测定结果分别与紫外-可见分光光度法和荧光光度法的测定结果相符。Glassy carbon electrode（GCE）was modified by dropping a suspension of graphene oxide（GO）,multi-walled carbon nanotubes（MWNTs）and carboxymethyl chitosan（CMCS）onto its surface to obtain the modified electrode of MWNTs/GO/CMCS/GCE.Electrochemical behaviors of NO2-and L-tryptophan（L-Trp）at the modified electrode were studied by cyclic voltammetry（CV）.The effective area of the modified electrode was found to be 3.243 0×10-6 cm2,which was significantly increased as compared with the bare electrode and thus electron transfer was accelerated and adsorption-enrichment of the analytes was facilitated.As shown by the results,significant electro-catalytic oxidations of NO2-（in PBS of pH 4.7）and L-Trp（in acetate buffer of pH 4.0）were observed at the modified electrode separately,and linear relationships between values of the oxidation peak current and the concentration of NO2-in the range of 1.0×10-7 to 3.5×10-1 mol·L-1 and of L-Trp in the range of 1.0×10-8 to 2.7×10-1 mol·L-1 were obtained,with detection limits（3 S/N）of 1.2×10-8 mol·L-1,and 5.0×10-8 mol·L-1 respectively.NO2-in a sample of rotten cos lettuce and L-Trp in a simulated sample were determined by the proposed CV method,giving results in consistency with those found by UV-spectrophotometry（for NO2-）and by fluorospectrophotometry（for L-Trp）.

关 键 词：电化学 亚硝酸根 L-色氨酸 氧化石墨烯 羧甲基壳聚糖 多壁碳纳米管 修饰电极 

分 类 号：O657.1[理学—分析化学]