羧基化高纯单壁碳纳米管修饰电极对乙酰甲喹的高灵敏检测

High sensitivity detection of mequindox by carboxylated high purity single wall carbon nanotubes modified electrode

摘要:

为保障食品安全，实现食品中乙酰甲喹残留的快速高灵敏检测，采用羧基化高纯单壁碳纳米管固载于金电极表面，以此构筑新型乙酰甲喹电化学传感器。运用循环伏安法（CV）、差分脉冲伏安法（DPV）和电化学交流阻抗法（EIS）等考察了传感器的性能。结果显示，该传感器对乙酰甲喹的电化学还原具有显著的催化性能，修饰电极的峰电流达到128.4 μA，是裸电极峰电流1160倍。对影响传感器性能的因素进行了优化。实验的最优条件为cSWCNTs涂覆量为4 μL，搅拌速度1000 rpm，pH=7.0 PBS缓冲液浓度为0.2 mol/L，0.5 V电压下富集30 min。在最优实验条件下 ，该传感器的峰电流与乙酰甲喹在1.0 ~500.0 nmol/L范围内呈良好的线性关系，相关系数为0.998，方法的检出限为0.76 nmol/L。该传感器被成功地应用于实际样品检测，加标回收率在81.7%~124 .0%。

Abstract:

In order to ensure food safety and realize the rapid and sensitive detection of mequindox residue in food, carboxylated high purity single-walled carbon nanotubes were fixed on the surface of the gold electrode to construct a novel mequindox electrochemical sensor. Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance (EIS) were used to investigate the performance of the sensor. The results showed that the performed sensor had remarkable catalytic performance on the electrochemical reduction of mequindox. The peak current of the modified electrode reached as 128.4 A, which was 1,160 times that of the bare gold electrode. The factors affecting the performance of the performed sensor were also optimized. The optimal conditions for the experiment were that the coated volume of cSWCNTs were 4 μL, the stirred speed was sat as 1000 rpm, and the performed electrode was enriched at 0.5 V in 0.2 mol/L PBS buffer (pH=7.0) for 30 min. Under the optimal experimental conditions, the peak current of the sensor had a good linear relationship with mequindox in the concentration range of 1.0~500.0 nmol/L, the correlation coefficient was 0.998, and the detection limit of the method was 0.76 nmol/L. The sensor was successfully applied to the actual sample detection with the standard recovery rate of 81.7%-124 %.