Simple, rapid, and instrument-free detection of cadmium ions (Cd²⁺) with a portable device is essential to prevent the contamination of potable water. Herein, we propose a simple, fast, and low-cost method for the real-time/on-site detection of Cd²⁺ using glutathione-modified Au nanoparticles (GSH-AuNPs) deposited on a polyethylene terephthalate (PET) sensor strip. To fabricate the sensor strip, a paint composed of GSH-AuNPs and polyvinylpyrrolidone was prepared. Subsequently, the GSH-AuNP paint was deposited on a mold fixed on the PET substrate and dried in ambient air. The GSH-AuNPs deposited on the PET substrate quickly redispersed in water, turning the water red. However, the GSH-AuNPs aggregated in water samples containing Cd²⁺, turning the water blue. The limit of detection of this Cd²⁺ sensor strip is 18.8 nM, which is comparable to the maximum contamination level of 44.5 nM Cd²⁺ in potable water stipulated by the US Environmental Protection Agency. Finally, we demonstrate that the GSH-AuNP-based sensor strip can be used in the on-site detection of Cd²⁺ in real samples such as tap water.

使用便携式设备对镉离子 (Cd ²⁺ ) 进行简单、快速且无需仪器的检测对于防止饮用水污染至关重要。在此，我们提出了一种简单、快速和低成本的方法，用于使用沉积在聚对苯二甲酸乙二醇酯 (PET) 传感带上的谷胱甘肽修饰的 Au 纳米粒子 (GSH-AuNPs)实时/现场检测 Cd ²⁺。为了制造传感带，制备了由 GSH-AuNPs 和聚乙烯吡咯烷酮组成的涂料。随后，将 GSH-AuNP 涂料沉积在固定在 PET 基材上的模具上，并在环境空气中干燥。沉积在 PET 基材上的 GSH-AuNPs 迅速重新分散在水中，使水变红。然而，在含有 Cd ^{2+ 的}水样中聚集的 GSH-AuNPs，把水变成蓝色。该 Cd ²⁺感应条的检测限为 18.8 nM，与美国环境保护署规定的饮用水中 44.5 nM Cd ²⁺的最大污染水平相当。最后，我们证明了基于 GSH-AuNP 的传感带可用于现场检测自来水等实际样品中的 Cd ²⁺。