Electrode Modified with the Ionic Liquid [P6,6,6,14+]2[MnCl42-] for the Determination of Bisphenol A in Plastic Samples

This paper describes a new and simple electrode for the determination of bisphenol A (BPA) in different plastic samples using carbon paste electrode (CPE) modified with a trihexyltetradecylphosphonium tetrachloromanganate(II) ([P6,6,6,14+]2[MnCl42-]) magnetic ionic liquid (MIL/CPE). Electrochemical characterization of MIL/CPE by cyclic voltammetry and electrochemical impedance spectroscopy indicated that MIL facilitated the electron transfer. Using squarewave voltammetry (SWV) under optimized conditions, the calibration curve showed a linear range for BPA from 2.0 to 53.0 µmol L-1, with limit of detection (LOD) of 0.87 µmol L-1. The proposed electrode demonstrated good precision with coefficients of variation of 4.5% (intra-day, n = 10), 2.0% (inter-day, n = 5) and 1.5% (electrode-to-electrode repeatability, n = 3). Recoveries of 93.0 to 101.1% demonstrated that the method is suitable for practical applications.

本研究报道了一种用于检测不同塑料样品中双酚A (bisphenol A, BPA) 的新型简便电极，该电极为经三己基十四烷基鏻四氯锰(II) ([P₆,₆,₆,₁₄⁺]₂[MnCl₄²⁻]) 磁性离子液体 (magnetic ionic liquid, MIL) 修饰的碳糊电极 (carbon paste electrode, CPE，简记为MIL/CPE)。采用循环伏安法与电化学阻抗谱对MIL/CPE进行电化学表征，结果表明该磁性离子液体可有效促进电子转移过程。在优化实验条件下采用方波伏安法 (squarewave voltammetry, SWV) 进行检测，校准曲线显示双酚A的线性检测范围为2.0~53.0 µmol·L⁻¹，检出限 (limit of detection, LOD) 为0.87 µmol·L⁻¹。该修饰电极展现出良好的精密度：日内精密度变异系数为4.5%（n=10）、日间精密度变异系数为2.0%（n=5），电极间重复性变异系数为1.5%（n=3）。加标回收率介于93.0%~101.1%之间，证实该方法具备实际应用可行性。