A Sensor for Detecting Aqueous Cu2+ That Functions in a Just-Add-Water Format

There is growing concern around the negative health impacts associated with contamination of drinking water by harmful chemicals. Technology that enables fast, cheap, and easy detection of ions and small molecules in drinking water is thus important for reducing the incidence of these negative health impacts. Here, we describe a sensor for detecting Cu2+ in water that provides colorimetric results in 15 min or less and functions in a just-add-water format. The sensor contains cheap reagents including salts, buffer, oxidant, chromogen, surfactant, and optionally a chelating agent. The sensor is assembled and lyophilized for shelf-stability and field-deployment. Rehydrating the sensor with water containing Cu2+ results in chromogen oxidation and blue color formation to visually indicate the presence of Cu2+. The sensor demonstrates high selectivity toward Cu2+ against other metal cations, functionality in field samples, shelf-stability, and can be tuned to activate at different Cu2+ threshold concentrations. This sensor thus has the potential to meet a variety of needs, such as point-of-need testing for Cu2+ to ensure water supplies meet health guidelines, such as the United States Environmental Protection Agency’s Lead and Copper Rule.

有害化学品污染饮用水所引发的负面健康影响，正日益受到广泛关注。因此，能够快速、低成本且简便地检测饮用水中离子与小分子的技术，对于降低此类负面健康影响的发生率至关重要。本研究介绍一款可检测水中铜离子（Cu²+）的传感器：该传感器可在15分钟内出具比色检测结果，且采用加水即用的便捷操作模式。该传感器所用试剂成本低廉，涵盖盐类、缓冲剂、氧化剂、显色剂、表面活性剂，以及可选添加的螯合剂。为实现货架稳定性与现场部署能力，该传感器经组装后进行了冷冻干燥处理。将含铜离子的水样与该传感器复溶后，会引发显色剂氧化并产生蓝色，从而直观显示铜离子的存在。该传感器对铜离子展现出相较于其他金属阳离子的高选择性，可在现场样本中正常发挥功能，具备良好的货架稳定性，且可通过调整参数使其在不同的铜离子阈值浓度下触发响应。因此，这款传感器有望满足多种应用需求，例如开展铜离子的现场即时检测，以确保供水符合健康标准，如美国环境保护署的《铅与铜规则》。