Dissolved lead is a serious but common health hazard in drinking water, yet there is still no practical way to monitor its levels continuously in the distribution system or at the point of use. Here we propose using a lead-selective membrane on top of a chemiresistive device to continuously measure Pb²⁺ ion concentrations in real time. The detection limit was lowered by stabilizing the surface of the resistive film with sodium hydroxide and 15-crown-5 ether and optimizing the sensor geometry to maximize the effective surface area. The detection mechanism is based on the complexation of the Pb²⁺ ions by the lead ionophores within the membrane, thus modulating the interactions between the ionophores and the chemiresistive film. The limit of detection of the fabricated devices was reliably below 2 μg L⁻¹, with concentrations up to 3 mg L⁻¹ routinely quantifiable over several measurement cycles. The chemiresistive sensors can thus achieve lower detection limits than potentiometric devices while being more robust and simpler to fabricate by omitting the reference electrode. Ion-selective membrane-covered chemiresistors can therefore be deployed to continuously monitor drinking water sources and detect harmful levels of lead in real time.

中文翻译：

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一种用于在线监测水中铅离子的高灵敏度离子选择性化学电阻传感器

溶解铅是饮用水中一种严重但常见的健康危害，但仍然没有实用的方法来连续监测分配系统或使用点的溶解铅含量。在这里，我们建议在化学电阻装置顶部使用铅选择性膜来实时连续测量 Pb ²⁺离子浓度。通过用氢氧化钠和 15-冠-5 醚稳定电阻膜表面并优化传感器几何形状以最大化有效表面积，降低了检测限。检测机制基于膜内铅离子载体与Pb ²⁺离子的络合，从而调节离子载体和化学电阻膜之间的相互作用。所制造的装置的检测限可靠地低于2 μg L ^-1 ，在几个测量周期中可常规定量高达3 mg L ^-1的浓度。因此，化学电阻传感器可以实现比电位装置更低的检测限，同时通过省略参比电极而更加坚固且更易于制造。因此，可以部署离子选择性膜覆盖化学电阻器来连续监测饮用水源并实时检测有害的铅含量。