Pb2+ is one of the major environmental pollutants, which can be visually detected by surface plasmon resonance of nanoparticles. Paper based analytical device, as a newly developed microfluidic detection platform, is featured in cost-effective and suitable for on-site analysis. In this paper, a sensitive and portable detection method for Pb2+ was proposed, in which Pb2+ was electrokinetically stacked on the paper fluidic channel by geometric field amplification effect and visualized online by glutathione-modified silver nanoparticles. Colorimetric quantification of the visualized stacking band was conducted by smart phone camera. To avoid unfavorable influence from pH change on the surface plasmon resonance visualization, field amplification effect was introduced by geometric design of the paper fluidic channel. The enriched Pb2+ was clearly visible on the paper substrate, and the stacking band intensity was about four orders of magnitude enhanced, comparing to the intensity without stacking. A linear response to Pb2+ was observed in the range of 0.3-7.0 μM (R2 = 0.997) with a limit of detection of 86 nM and a limit of quantity of 0.28 μM. The established method was used in the detection of Pb2+ from river and lake water samples, and the results were confirmed by atomic absorption spectroscopy method.

中文翻译：

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通过几何场放大和表面等离振子共振可视化对Pb2 +进行比色检测。

Pb2 +是主要的环境污染物之一，可以通过纳米粒子的表面等离子体共振在视觉上检测到。纸质分析设备作为一种新开发的微流体检测平台，具有高性价比的特点，适用于现场分析。本文提出了一种灵敏，便携的Pb2 +检测方法，该方法通过几何场放大效应将Pb2 +电动堆叠在纸质流体通道上，并通过谷胱甘肽修饰的银纳米粒子在线显示。可视化堆叠带的比色定量通过智能手机相机进行。为了避免pH值变化对表面等离振子共振可视化的不利影响，通过纸流道的几何设计引入了场放大效应。与未堆积的强度相比，富集的Pb2 +在纸质基材上清晰可见，堆积带强度提高了约四个数量级。在0.3-7.0μM（R2 = 0.997）的范围内观察到对Pb2 +的线性响应，检测限为86 nM，量限为0.28μM。建立的方法用于河流和湖泊水样中Pb2 +的检测，结果经原子吸收光谱法证实。