Visual inspection is expected as an ideal technique, which can directly and conveniently detect heavy metal ions by observing the color change. Insensitivity of detecting weakly colored heavy transition metal ions and low adsorptivity of metal ions on nanoparticle surface are two main factors hindering the application of visual detection in heavy metal ions detection. Herein, we demonstrated an operational colorimetric sensor based on the color dependence of nanoparticles aggregation to selective and facile detect weakly colored transition heavy metal Cd²⁺ ions that have been considered as the origin of the “Itai-itai” disease. Uniform colloidal 15 nm graphite-like nitride doped carbon quantum dots-capped gold nanoparticle ([email protected]) was successfully prepared, wherein the existence of numerous heptazine, carboxyl and hydroxyl groups on the nanoparticle's surface strengthened adsorption of the Cd²⁺ ions on the surface of [email protected] through the “cooperative effect”. As a consequence, without expensive and intricate exogenous indicators or other special additives, the Cd²⁺ ions could sensitively and quickly captured to detect at ultra-low concentration within 30 s by the naked-eye. Under the optimal conditions, the Cd²⁺ ions sensor possesses good analytical performances with a wide linear range of 0.01–3.0 μM and a detection limit of 10 nM (S/N = 3). Moreover, the biodistribution and aggregation of Cd²⁺ ions were detected effectively in mice organ tissues suggesting its great potential use for real-word applications.

目视检查被认为是一种理想的技术，它可以通过观察颜色变化来直接方便地检测重金属离子。弱着色重过渡金属离子的检测不灵敏和纳米颗粒表面金属离子的低吸附性是阻碍视觉检测在重金属离子检测中应用的两个主要因素。在这里，我们展示了一种基于比色传感器的操作性比色传感器，该颗粒依赖于纳米粒子聚集对选择性和容易检测弱色过渡重金属Cd ^2+的依赖性被认为是“伊泰伊塔伊”病起源的离子。成功制备了均匀的胶体状的15 nm石墨状氮化物掺杂的碳量子点封端的金纳米粒子（[受电子邮件保护]），其中纳米粒子表面上存在大量的庚嗪，羧基和羟基增强了Cd ²⁺离子在碳纳米管上的吸附。通过“合作效应”保护[电子邮件受到保护]的表面。结果，在没有昂贵而复杂的外源指示剂或其他特殊添加剂的情况下，Cd ²⁺离子可以被肉眼灵敏快速地捕获，并在30 s内以超低浓度进行检测。在最佳条件下，Cd ²⁺离子传感器具有良好的分析性能，线性范围为0.01–3.0μM，检测极限为10 nM（S / N = 3）。而且，在小鼠器官组织中有效检测到了Cd ²⁺离子的生物分布和聚集，表明其在实词应用中具有巨大的潜在用途。