新型电聚合交联聚苯胺电化学传感器的研制及其在抗坏血酸测定中的应用

以苯胺、对苯二胺、1,3,5-三苯胺基苯为单体,采用循环伏安法在金电极上电化学聚合制备了一种新型的交联聚苯胺(CPAN)电化学传感器。采用交流阻抗谱和电化学方法对该传感器进行了表征。结果表明:交联剂1,3,5-三苯胺基苯结构单元被成功地引入到聚苯胺链中,所得的CPAN与线性聚苯胺(LPAN)相比,导电性增强,电子传输速率加快。CPAN/Au电极对抗坏血酸具有良好的电催化氧化作用,在优化的条件下,测得抗坏血酸浓度在1.0×10-4～1.0×10-2 mol.L-1范围内与传感器峰电流呈线性关系,检出限(3S/N)为3.3×10-5 mol.L-1。该传感器的响应时间为5s,测定结果的相对标准偏差(n=6)为2.0%～2.5%,回收率在98.0%～102%之间。

Preparation of a Novel Electrochemical Sensor of Electropolymerized Crosslinked Polyaniline and Its Application to the Determination of Ascorbic Acid

A novel electrochemical sensor of crosslinked polyaniline(CPAN) was modified on Au electrode by cyclic voltammetric electropolymerization using aniline,p-phenylenediamine and 1,3,5-tris(phenylamino) benzene as the monomers.The electrochemical sensor obtained was characterized by AC impedence graph and electrochemistry.It was shown by the experimental results,that the structural unit of crosslinking agent 1,3,5-tris(phenylamino) benzene was successfully introduced into polyaniline chain.In comparison with linear PAN,the CPAN showed greater conductivity enhancement and faster electronic transmission speed.The CPAN modified Au electrode exhibited excellent electrocatalytic responses towards the oxidation of ascorbic acid.Under the optimized conditions,linear relationship between values of peak current and concentration of ascorbic acid was found in the range of 1.0×10-4-1.0×10-2mol·L-1 with detection limit(3S/N) of 3.3 ×10-5mol·L-1.Time of response of the sensor was found within 5 s.Values of RSD(n=6) found were in the range of 2.0%-2.5%.Recovery was tested by standard addition method,giving results in the range of 98.0%-102%.