High Selective Detection of Trace Lead Ions via Substitution‐triggered Chemiluminescence Enhancement.

Lead ion (Pb2+) is a high‐hazardously heavy metal ion in surroundings that even ppb level can cause mental decline and behavioral difficulties especially in children. However, the recognition and detection of Pb2+ are still challenging. Here, a high selective and ultra‐sensitive chemiluminescence (CL) method was established based on the substitution mechanism between Pb2+ and the metal–organic framework – Cu‐MOF‐74. Pb2+ can specifically substitute Cu active sites in Cu‐MOF‐74 and released Cu sites, strongly amplifying the CL emission of the luminol‐hydrogen peroxide (H2O2) system. A linear response for Pb2+ detection in the range of 0.5–50 nM with a detection limit of 0.3 nM was realized. Moreover, the proposed method was successfully implemented on a paper‐based analytical device with favorable fabrication and operational features for Pb2+ determination in water samples. It offers a new strategy to design high selective and sensitive sensors for the heavy metal ions monitoring. [ABSTRACT FROM AUTHOR]