Postgraduate Program in Natural Resources, Universidade Estadual de Mato Grosso do Sul, Caixa Postal 351, Dourados, MS 79804-970, Brazil.
Postgraduate Program in Natural Resources, Universidade Estadual de Mato Grosso do Sul, Caixa Postal 351, Dourados, MS 79804-970, Brazil.
Mater Sci Eng C Mater Biol Appl. 2019 Dec;105:110048. doi: 10.1016/j.msec.2019.110048. Epub 2019 Aug 2.
A simple, inexpensive, highly sensitive, selective, and novel electrochemical method was developed for determination of the Bisphenol A in samples of tap water, blood serum, and urine using a bentonite-modified carbon paste electrode. The graphite, bentonite and the working electrodes (without and chemically modified) were characterized by scanning electron microscopy, infrared absorption spectroscopy, and X-ray diffraction. The electrodes were electrochemically characterized using cyclic voltammetry, square wave voltammetry, and electrochemical impedance spectroscopy. The studied electrochemical variables were: electrode area, standard heterogeneous rate constant, charge transfer coefficient and double-layer capacitance. The bentonite as a sensor modifier had a strong influence on these variables. For the development of the methodology to quantify Bisphenol A, the instrumental parameters (frequency, amplitude, and step potential) and experimental parameters (pH, bentonite quantity) were optimized. The analytical curve to Bisphenol showed a linear response of the oxidation peak current intensity vs. the concentration in the range of 6.8 × 10 to 1.5 × 10 mol mL, with a limit of detection (LOD) of 2.11 × 10 mol mL and limit of quantification (LOQ) of 7.04 × 10 mol mL. Recovery experiments were performed by adding known amounts of Bisphenol A in tap water, blood serum, and urine samples. Recovery rates using the standard addition method were in the range of 97.8-101.8%. The results demonstrated the method feasibility for quantifying Bisphenol A in these samples.
本工作采用膨润土修饰的碳糊电极，建立了一种简单、廉价、高灵敏度、选择性好的电化学方法，用于测定自来水中、血清中和尿中的双酚 A。通过扫描电子显微镜、红外吸收光谱和 X 射线衍射对石墨、膨润土和工作电极（未修饰和化学修饰）进行了表征。通过循环伏安法、方波伏安法和电化学阻抗谱对电极进行了电化学表征。研究了电化学变量：电极面积、标准异质速率常数、电荷转移系数和双层电容。膨润土作为传感器修饰剂对这些变量有很大的影响。为了开发定量测定双酚 A 的方法，对仪器参数（频率、幅度和阶跃电位）和实验参数（pH 值、膨润土用量）进行了优化。双酚 A 的分析曲线显示氧化峰电流强度与浓度在 6.8×10 到 1.5×10 mol mL 范围内呈线性响应，检测限（LOD）为 2.11×10 mol mL，定量限（LOQ）为 7.04×10 mol mL。通过向自来水中、血清中和尿样中加入已知量的双酚 A 进行了回收实验。标准加入法的回收率范围为 97.8-101.8%。结果表明该方法适用于这些样品中双酚 A 的定量分析。
