Khan Sami Ullah, Khalid Waqas, Atif Muhammad, Ali Zulqurnain
Smart Surfaces and Materials Group, Functional Materials Lab, Department of Physics, Air University PAF Complex Islamabad Pakistan
RSC Adv. 2024 Sep 2;14(38):27862-27872. doi: 10.1039/d4ra04406a. eCollection 2024 Aug 29.
This research presents a novel approach for the detection of the pesticide chlorpyrifos (CLP) using a gold working electrode immobilized with a graphene oxide-cerium oxide (GO-CeO) nanocomposite in a phosphate buffer (PBS) solution with a pH of 7.0. Graphene oxide (GO) was synthesized a modified Hummer's method, while cerium oxide (CeO) nanoparticles were prepared using a coprecipitation technique. The GO-CeO nanocomposite was synthesized sonochemical methods. Structural and morphological characterization of the prepared material was conducted using X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDX). Fourier transform infrared (FTIR) spectroscopy has been conducted for the confirmation of functional group presence in the prepared materials. Cyclic voltammetry (CV) was employed to investigate the interaction between the prepared material and the analyte. Further investigations using varying scan rates (5 mV s to 300 mV s) revealed a diffusion-controlled process at the electrode-electrolyte interface. Linear sweep voltammetry (LSV) experiments were conducted across a pH range of 5 to 9, with pH 7.0 showing enhanced response for the target pesticides in the presence of the buffer solution. Subsequent electrochemical measurements were performed at pH 7.0. Chronocoulometry was utilized to measure the effective electrode area for electrochemical interactions. Ultrasensitive square wave voltammetry (SWV) was employed for investigating the sensitivity over a concentration range of 1 fM to 100 μM and yielded the limit of detection (LOD) and limit of quantification (LOQ) as 47.7 fM and 159 fM respectively. Interference studies confirmed the selectivity of the prepared sensor, while stability and reproducibility were assessed through controlled experiments. Electrochemical impedance spectroscopy (EIS) was performed to investigate the interactions at the interface. This study provides insights into the development of selective electrochemical sensors for pesticide detection, with potential applications in environmental monitoring.
本研究提出了一种在pH值为7.0的磷酸盐缓冲液（PBS）中，使用固定有氧化石墨烯-氧化铈（GO-CeO）纳米复合材料的金工作电极检测农药毒死蜱（CLP）的新方法。氧化石墨烯（GO）采用改进的Hummer法合成，而氧化铈（CeO）纳米颗粒则采用共沉淀技术制备。GO-CeO纳米复合材料通过超声化学方法合成。使用X射线衍射（XRD）、扫描电子显微镜（SEM）以及能量色散光谱（EDX）对制备材料进行结构和形态表征。利用傅里叶变换红外（FTIR）光谱确认制备材料中官能团的存在。采用循环伏安法（CV）研究制备材料与分析物之间的相互作用。进一步以不同扫描速率（5 mV/s至300 mV/s）进行的研究揭示了电极-电解质界面处的扩散控制过程。在pH值为5至9的范围内进行线性扫描伏安法（LSV）实验，结果表明在缓冲溶液存在下，pH值为7.0时对目标农药的响应增强。随后在pH值为7.0时进行电化学测量。采用计时库仑法测量电化学相互作用的有效电极面积。利用超灵敏方波伏安法（SWV）研究1 fM至100 μM浓度范围内的灵敏度，检测限（LOD）和定量限（LOQ）分别为47.7 fM和159 fM。干扰研究证实了所制备传感器的选择性，同时通过对照实验评估了稳定性和重现性。进行电化学阻抗谱（EIS）以研究界面处的相互作用。本研究为开发用于农药检测的选择性电化学传感器提供了见解，在环境监测中具有潜在应用。
