光电子调控的聚苯胺氧化还原反应用于铜离子可视化检测

构建了由中间价态聚苯胺(ES-PANI)和二氧化钛(TiO2)纳米粒子组成的光致变色检测平台,用于痕量铜可视化检测.在紫外光激发下,ES-PANI(墨绿色)会被TiO2产生光生空穴氧化为完全氧化态聚苯胺(深蓝色);随着Cu2+的加入,ES-PANI生成还原态聚苯胺(浅黄色),导致一系列可由肉眼观测到的颜色变化.光致变色过程中的颜色转变取决于Cu2+调控的不同价态聚苯胺.本方法结合了光电化学和可视化检测的优点,在Cu2+的检测中表现出了高选择性和灵敏度,检出限为0.4μmol/L.采用Photoshop软件读取绿通道平均强度值和用酶标仪记录紫外吸收值,发展了另外两种定量检测方法.此外,将本方法用于人类头发实际样品中Cu2+的定量检测,回收率令人满意.所建立的检测平台简单、成本低廉,无需复杂的仪器即可在几分钟内同时检测多种样品.这种光电子调控的比色策略为设计新型比色检测平台提供了新思路,并且可望应用于临床快速诊断便携试剂盒的开发.

Photoelectron-Regulated Redox Reaction of Polyaniline for Visual Detection of Trace Copper

A photochromic sensing platform composing of emeraldine salt of polyaniline ( ES-PANI ) and titanium dioxide nanoparticles ( TiO2 NPs) for visual detection of trace copper was developed. Under ultraviolet light irradiation, the greenish ES-PANI could be oxidized to dark blue pernigraniline salt by the photogenerated hole of excited TiO2 NPs. In the presence of Cu2+, a light yellow leucoemeraldine salt was visually observed. The overall mechanism of color change was verified to be corresponding to the different redox states of PANI regulated by Cu species during the photochromic process. By integrating the advantages of both photoelectric property and visual detection, the redox reaction-based sensing mechanism led to a good sensitivity and high selectivity in the detection of Cu2+ with the detection limit of 0. 4 μmol/L. Besides the naked eye, two color recognition methods including reading mean green intensities in Photoshop and recording ultraviolet absorbance in microplate reader were also studied. This method was successfully applied to Cu2+ detection in human hair with satisfactory recoveries. More significantly, this sensing platform was really simple, low-cost and able to detect an array of analytes within several minutes without requiring sophisticated equipment. This photoelectron-regulated colorimetric strategy provided a novel concept for the design of visual sensing platform, and could develop the portable test kits for rapid detection in clinical diagnosis.