单壁碳纳米管-纳米金-离子液体修饰玻碳电极用于线性伏安法测定辛硫磷

Linear Voltammetric Determination of Phoxim Using SWCNTsnano Au-BMIMPF_6 Modified GCE as Working Electrode

将单壁碳纳米管(SWCNTs)悬浊液和纳米金(nano Au)溶液混匀后滴涂在玻碳电极表面,自然干燥后再将离子液体BMIMPF6的甲醇溶液滴涂在上述电极上,制得单壁碳纳米管-纳米金-离子液体修饰玻碳电极(SWCNTs-nano Au-BMIMPF6/GCE)。用循环伏安方法研究了辛硫磷在pH 4.0的磷酸盐支持电解质中,在电位-1.1～-0.1V(vs.SCE)范围内,在修饰电极上的电化学行为。结果表明:在电位-0.81V处可见明显的还原峰,且其峰电流与辛硫磷的浓度在6.0×10-7～1.2×10-3 mmol.L-1范围内呈线性关系,检出限(3S/N)为3.0×10-7 mmol.L-1。据此提出了用线性伏安法测定辛硫磷的方法,用标准加入法测得其回收率在96.0%～105.5%之间,测定值的相对标准偏差(n=6)在3.3%～3.9%之间。

A mixture of dispersion of SWCNTs and nano Au solution was added dropwise onto the surface of glassy carbon electrode （GCE）, after air-drying, methanol solution of ionic liquid, BMIMPF6 was added dropwise onto the surface of the above electrode. The modified electrode, designated as SWCNTs-nano Au-BMIMPF6/GCE was thus prepared. Electrochemical behavior of phoxim at the modified electrode was studied by cyclic voltammetry in a phosphate buffer supporting electrolyte of pH 4. 0 in the potential range of --1.1 to --0. 1 V （vs. SCE）. As shown by the experimental results, a significant reduction peak was observed at --0. 81 V, and linear relationship between values of reduction peak current and concentration of phoxim was kept in the range of 6.0×10-7 to 1.2×10-3mmol·L-1 , with detection limit （3S/N） of 3. 0×10-7 mmol ·L-1. Based on these findings, a method for determination of phoxim by linear voltammetry was proposed. Recovery was tested by standard addition method, giving values of recovery and RSD＇s （n=6） in the ranges of 96.0%--105.5% and 3.3%--3.9% respectively.