辣根过氧化物酶修饰电极在离子液体[EMIM]BF4中的直接电化学  

Direct Electrochemistry of Horseradish Peroxidase Modified Electrode in Ionic Liquid [EMIM]BF_4

作　　者：张亚[1,2] 张宏芳[1] 郑建斌[1] 

机构地区：[1]西北大学分析科学研究所／陕西省电分析化学重点实验室,西安710069 [2]榆林学院化学与化学工程学院,榆林719000

出　　处：《化学学报》2008年第19期2124-2130,共7页Acta Chimica Sinica

基　　金：国家自然科学基金(No.20675062);高等学校博士学科点专项科研基金(No.20060697013);西北大学研究生自主创新基金(No.07YZZ18)资助项目

摘　　要：将壳聚糖(Chi)-辣根过氧化物酶(HRP)-多壁碳纳米管(MWCNTs)的复合物修饰在玻碳电极(GCE)表面,制备了HRP修饰电极(Chi-HRP-MWCNTs/GCE),并将其用于在亲水性离子液体1-乙基-3-甲基咪唑四氟硼酸([EMIM]BF4)中HRP的直接电化学研究.紫外可见光谱和红外光谱表明,HRP在复合物内保持了其原始构象.电化学研究表明,该修饰电极在[EMIM]BF4中的循环伏安图上出现了一对峰形良好、几乎对称的氧化还原峰,式量电位为-0.247V(vs.Ag/AgCl),说明包埋在Chi-MWCNTs中的HRP与电极之间发生了直接电子传递;HRP在电极表面直接电子转移的速率常数ks为3.12s-1;在65℃的[EMIM]BF4中HRP仍然保持其活性;HRP修饰电极对过氧化氢的还原具有电催化作用,其表观米氏常数Km为5.6×10-5molL-1,催化电流与过氧化氢浓度在5.0×10-7～5.0×10-5mol·L-1范围内呈线性关系,检出限为2.0×10-7mol·L-1.该研究为非水相生物传感器的构制提供了一种新途径.A horseradish peroxidase （HRP） modified glass carbon electrode （GCE） was fabricated by using composite of multi-walled carbon nanotubes （MWCNTs）, HRP and chitosan （Chi） as modifier. UV-Vis and IR spectroscopy of HRP showed that HRP retained its native structure in the composite. The Chi-HRPMWCNTs/GCE was applied to investigation on the direct electrochemistry of HRP in a hydrophilic ionic liquid, 1-ethyl-3-methylimidazolium tetrafluroborate （[EMIM]BF4）. The cyclic voltammetric experiment results of HRP indicated that HRP exhibited a pair of well-defined and nearly symmetrical redox peaks with a formal potential of --0.247 V （vs. Ag/AgCl） in [EMIM]BF4, which resulted from the direct electron transfer between entrapped HRP and the underlying electrode. The electron transfer rate constant （ks） of HRP on the electrode surface was 3.12 s^-1. HRP could maintain excellent activity in [EMIM]BF4 at 65℃. Further experiment demonstrated that the HRP modified electrode exhibited an electrocataiytic activity for the reduction of H202. The catalytic peak current was linear to H202 concentration in the range of 5.0 × 10^-7 to 5.0× 10^-5 mol.L^-1, with a detection limit of 2.0× 10^-7 mol·L^-1. The apparent Michaelis-Menten constant （Kin） was estimated to be 5.6 × 10^-5 mol·L^-1. This study can provide a new approach for developing a nonaqueous biosensor.

关 键 词：电化学 电催化 离子液体 碳纳米管 辣根过氧化物酶 过氧化氢 

分 类 号：O646.54[理学—物理化学]