含Fe(Ⅲ)离子有机-无机层状类钙钛矿杂合物修饰电极对对苯二酚的电催化作用及测定

Electrocatalytic Determination of Hydroquinone Based on Organic-Inorganic Layered Perovskite Hybrid Containing Fe^(3+) Modified Carbon Paste Electrode

以酚藏花红为有机层、含三价铁的K3Fe(CN)6为无机层在空气中合成了有机-无机层状类钙钛矿杂合物修饰碳糊电极。利用扫描电镜(SEM)和X-射线衍射(XRD)对其表面形貌和微观结构进行表征,并用循环伏安法研究了杂合物修饰电极的电化学性质,发现该电极对对苯二酚具有良好的电催化作用。结果表明,在pH5.0的PBS缓冲溶液中,对苯二酚在空白碳糊电极上为二步还原过程而在修饰电极上只有一步还原过程,修饰电极更有利于检测对苯二酚。采用微分脉冲伏安法在-0.4～0V电位范围内进行扫描,在-240.2mV处的还原峰电流与对苯二酚浓度在1.0×10-6～1.0×10-3mol/L范围呈良好的线性关系,相关系数为0.9951,检出限为4.73×10-7mol/L。对1.0×10-5mol/L的对苯二酚连续测定5次,相对标准偏差为1.8%。模拟样品中对苯二酚的平均加标回收率为102%。

A modified carbon paste electrode （ CPE ） was constructed by organic - inorganic layered perovskite hybrid enveloped in paraffin. Layered organic - inorganic perovskite hybrid containing Fe^3＋ was synthesized in the air with phenosafranine as organic sheets, and K3Fe（CN） 6 as inorganic sheets. The results of X-ray diffractometry（XRD） and scanning electron microscope （SEM） showed that the conformation was typical layered perovskite structure. In pH 5.0 phosphate buffer solution, the electrochemical characteristic of the modified electrode was studied by cyclic vohammetry（CV）. The influences of experimental parameters on modified electrode were investigated. The results indicated that the modified electrode exhibited a high electrocatalytic activity toward hydroquinone. Compared with bare CPE, the modified electrode by hybrid made the two reduction steps of hyroquinone become one step. The peak current of hydroquinone on the modified electrode was proportional to the concentration of hydroquinone in the range of 1.0 × 10^-6- 1.0× 10^-3 mol/L with a correlation coefficient of 0. 995 1. The detection limit was 4.73 ×10^-7 mol/L. For 5 parallel measurements of 1.0 × 10^-5 mol/L hydroquinone, the relative standard deviation was found to be 1.8% . It was verified that other phenols would not interfere with the determination of hydroquinone. The prepared electrode showed good stability and reproducibility. The mean recovery of hydroquinone from the sinmlated water sample was 102% .