Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, PR China.
Anal Chim Acta. 2013 Jun 27;785:34-42. doi: 10.1016/j.aca.2013.04.050. Epub 2013 May 13.
A new, highly sensitive bifunctional electrochemical sensor for the simultaneous determination of pentachlorophenol (PCP) and copper ions (Cu(2+)) has been developed, where organic-inorganic hybrid ultrathin films were fabricated by alternate assembly of humic acid (HA) and exfoliated Mg-Al-layered double hydroxide (LDH) nanosheets onto ITO substrates via a layer-by-layer (LBL) approach. The multilayer films were then characterized by means of UV-vis spectrometry, scanning electron microscopy (SEM), and atomic force microscope (AFM). These films were found to have a relatively smooth surface with almost equal amounts of HA incorporated in each cycle. Its electrochemical performance was systematically investigated. Our results demonstrate that such a newly designed (LDH/HA)n multilayer films, combining the individual properties of HA (dual recognition ability for organic herbicides and metal ions) together with LDH nanosheets (a rigid inorganic matrix), can be applied to the simultaneous analysis of PCP and Cu(II) without interference from each other. The LBL assembled nanoarchitectures were further investigated by X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (IR), which provides insight for bifunctional sensing behavior. Under the optimized conditions, the detection limit was found to be as low as 0.4 nM PCP, well below the guideline value of PCP in drinking water (3.7 nM) set by the United States Environmental Protection Agency (U.S. EPA), and 2.0 nM Cu(2+), much below the guideline value (2.0 mg L(-1), ~31.2 nM) from the World Health Organization (WHO), respectively. Toward the goal for practical applications, this simple and cost-effective probe was further evaluated by monitoring PCP and Cu(II) in water samples.
一种新的、高灵敏度的双功能电化学传感器，用于同时测定五氯苯酚（PCP）和铜离子（Cu(2+)），已被开发出来。通过层层（LBL）方法，将腐殖酸（HA）和剥离的 Mg-Al 层状双氢氧化物（LDH）纳米片交替组装到 ITO 基底上，制备了有机-无机杂化超薄薄膜。然后通过紫外-可见分光光度法、扫描电子显微镜（SEM）和原子力显微镜（AFM）对多层膜进行了表征。结果发现，这些薄膜具有相对光滑的表面，每个循环中几乎等量地掺入 HA。系统地研究了其电化学性能。我们的结果表明，这种新设计的（LDH/HA)n 多层膜，结合了 HA（对有机除草剂和金属离子的双重识别能力）与 LDH 纳米片（刚性无机基质）的各自特性，可以应用于 PCP 和 Cu(II)的同时分析，而不会相互干扰。通过 X 射线光电子能谱（XPS）和红外光谱（IR）进一步研究了 LBL 组装的纳米结构，为双功能传感行为提供了深入的了解。在优化条件下，检测限低至 0.4 nM PCP，远低于美国环境保护署（U.S. EPA）规定的饮用水中 PCP 指导值（3.7 nM），检测限低至 2.0 nM Cu(2+)，远低于世界卫生组织（WHO）规定的指导值（2.0 毫克/升（~31.2 nM））。为了实现实际应用的目标，该简单且具有成本效益的探针进一步通过监测水样中的 PCP 和 Cu(II)进行了评估。
