Anal Chem. 2018 Oct 2;90(19):11517-11522. doi: 10.1021/acs.analchem.8b02808. Epub 2018 Sep 14.
Lead ions (Pb) contamination in drinking water, a major source of lead poisoning to the general population, is typically detected by bulky and costly laboratory analytical instrument. A mobile analytical device for rapid Pb sensing is a growing demand. Herein, we report smartphone nanocolorimetry (SNC) as a new technique to detect and quantify dissolved Pb in drinking water. Specifically, we have employed a single-step sedimentation approach by mixing a controlled quantity of chromate ion (CrO) to react with Pb containing solutions to form highly insoluble lead chromate (PbCrO) nanoparticles as vivid yellow precipitates. This is followed by microscopic color detection and intensity quantitation at nanoscale level using dark-field smartphone microscopy. The sum of the intensity of yellow pixels bears a highly reproducible relationship with Pb concentration between 1.37 and 175 ppb in deionized water and 5-175 ppb in city tap water. In contrast to traditional colorimetric techniques analyzing bulk color changes, SNC achieves unparalleled sensitivity by combining nanocolorimetry with dark-field microscopy and mobilized the metal ions detection by integrating the detection into the smartphone microscope platform. SNC is rapid and low-cost and has the potential to enable individual citizens to examine Pb content in drinking water on-demand in virtually any environmental setting.
饮用水中的铅离子 (Pb) 污染是导致大众铅中毒的主要来源，通常需要使用体积庞大且昂贵的实验室分析仪器进行检测。因此，人们对于快速铅感应的移动分析设备的需求日益增长。在此，我们报告了智能手机纳米比色法 (SNC) 作为一种新的技术，用于检测和量化饮用水中的溶解铅。具体而言，我们采用了一步沉淀法，通过混合一定量的铬酸根离子 (CrO) 与含铅溶液反应，形成高度不溶的铬酸铅 (PbCrO) 纳米颗粒，呈现出鲜艳的黄色沉淀。然后，使用暗场智能手机显微镜在纳米级水平上进行微观颜色检测和强度定量。黄色像素的总和与去离子水中的 Pb 浓度在 1.37 至 175 ppb 之间以及城市自来水中的 5 至 175 ppb 之间存在高度可重现的关系。与分析整体颜色变化的传统比色技术不同，SNC 通过将纳米比色法与暗场显微镜相结合，并通过将检测集成到智能手机显微镜平台上来实现对金属离子的检测，从而达到了无与伦比的灵敏度。SNC 快速且成本低廉，具有使个体公民在几乎任何环境条件下按需检测饮用水中 Pb 含量的潜力。
