磷钨酸改性蒙脱土-离子液体修饰电极上百草枯的电化学行为及测定

Electrochemical Behaviour and Determination of Paraquat on the Glassy Carbon Electrode Modified with Montmorillonite and Ionic Liquid

该文制备了磷钨酸改性蒙脱土-离子液体修饰电极（PTA—MMT-[BMIM]PF6／GCE），用红外光谱对PTA—MMT和[BMIM]PR进行了表征。通过对比改性前后电极的交流阻抗图，发现PQ在PTA—MMT-[BMIM]PF6／GCE上电荷转移的电阻最小。研究了百草枯（PQ）在该修饰电极上的循环伏安行为。结果表明，在pH8．0的PBS缓冲液中，PQ在该修饰电极上出现两对氧化还原峰。在40～360mY·s^-1扫速范围内，氧化峰电流与扫速呈线性关系，表明该电极过程受吸附控制。测得PQ在修饰电极上的反应电子数和电极有效面积分别为2和0．0644cm^2。讨论了修饰剂用量、缓冲液种类、溶液pH值对测定的影响。用方波伏安法对PQ进行测定．氧化峰电流（Ipa）与PQ在5．0×10-72．5×10^-4mol·L^-1的浓度范围内呈良好线性，线性方程为Ips（μA）=-1．024—23．683c（10-^-4mol·L^-1），相关系数为0．9993，检出限为2．07×10^-7mol·L^-1，加标回收率为93％-104％。该修饰电极具有良好的重复性和稳定性。

A novel PTA -MMT and [ BMIM ] PF6 modified glassy carbon electrode （PTA -MMT- [ BMIM ] PF6/GCE） was prepared and successfully used for the determination of paraquat（PQ）. The modified film was characterized by infared （IR） spectrometry. The charge transfer resistance of PQ on PTA - MMT - [ BMIM ] PF6/GCE was the lowest by comparing the nyquist plots of the electrode before and after modification. The cyclic voltammetric behavior of PQ on modified electrode was studied. The results showed that, in pH 8.0 phosphate buffer solution（ PBS）, two pairs of redox peaks were observed on the modified electrode. The oxidation peak current was linear to scan rates in the range of 40 - 360 mV - s ^-1 , indicating that the electrode process of PQ was controlled by absorption. The reaction electronic number and active area of PQ on PTA - MMT - [ BMIM ] PF6/GCE were obtained to be 2 and 0. 064 4 cm2, respectively. The effects of modifier dosage, buffer solution types and pH values for the determination of PQ were discussed. Under the optimized conditions, the correlation between peak current （lea） and PQ concentration was studied by square wave voltammetry, and a good linear relationship was obtained over PQ concentration in the range of 5.0 × 10-7 - 2.5 × 10^-4 mol · L^-1. The linear equation was Ipa （μA） = - 1. 024 - 23. 683c （ r = 0. 999 3 ） and the detection limit was 2.07 ×10-7 mol · L^-1 The spiked recoveries were in the range of 93% -104%. The modified electrode exhibited good repeatability and stability.