Tianjin Key Laboratory of Molecular Optoelectronic, Department of Chemistry, School of Science, Tianjin University, Tianjin 300072, P. R. China.
Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou 730070, P. R. China.
Anal Chem. 2022 Jul 26;94(29):10462-10469. doi: 10.1021/acs.analchem.2c01665. Epub 2022 Jul 14.
Heavy metal ions seriously threaten human health; even a trace of them can damage the renal, nervous, and immune systems irreversibly. Although established nanozyme-based colorimetric assays have been designed for the rapid detection of heavy metal ions, the general contained surface organic ligands of nanocatalysts and low absorptivity of metal ions on solid substrates might result in a weak effect on active sites and prevent the realization of their full detection potential. Here, we developed a nanozyme-based colorimetric sensor (CPM-Pt) made by pyrolysis of peat moss with preabsorbed traces of Pt ions to ultrasensitively detect Ag. The calcination removes organic components and produces bare nanozymes that expose rich active sites. The strong protective effect from the porous carbon support enables the embedded Pt nanoparticles (Pt NPs) with a partially stable positive charge after pyrolysis (∼28% Pt species). By the - metal-metal interactions between Pt (45) and Ag (4), the high proportion of Pt species on the surface of Pt NPs can readily capture/absorb Ag. Subsequently, Ag accepts electrons from the support to form Ag atoms, which rapidly cover the peroxidase-like active sites of bare Pt NPs, weakening the activation of HO to realize the response of Ag. The colorimetric detection limit of Ag reached an unprecedented 1.1 pM, and the corresponding naked-eye color recognition is ultrasensitive to extremely low levels (100 pM).
重金属离子严重威胁人类健康；即使是微量的重金属离子也会对肾脏、神经系统和免疫系统造成不可逆转的损害。尽管已经设计出基于纳米酶的比色测定法来快速检测重金属离子，但纳米催化剂中通常包含的表面有机配体和金属离子在固体基质上的低吸收率可能导致活性位点的作用减弱，并阻止其充分发挥检测潜力。在这里，我们开发了一种基于纳米酶的比色传感器（CPM-Pt），它是由预先吸附痕量 Pt 离子的泥炭热解而成，用于超灵敏地检测 Ag。煅烧去除了有机成分，产生了裸露的纳米酶，暴露了丰富的活性位点。多孔碳载体的强烈保护作用使嵌入的 Pt 纳米颗粒（PtNPs）在热解后具有部分稳定的正电荷（约 28%的 Pt 物种）。通过 Pt（45）和 Ag（4）之间的 - 金属-金属相互作用，PtNPs 表面的高比例 Pt 物种可以轻易地捕获/吸收 Ag。随后，Ag 从载体接受电子形成 Ag 原子，这些 Ag 原子迅速覆盖裸露的 PtNPs 的过氧化物酶样活性位点，从而削弱 HO 的活化，实现对 Ag 的响应。Ag 的比色检测限达到了前所未有的 1.1 pM，对应的肉眼颜色识别对极低水平（100 pM）也非常敏感。
