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

Abstract Lead ion (Pb 2+ ) 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 Pb 2+ are still challenging. Here, a high selective and ultra‐sensitive chemiluminescence (CL) method was established based on the substitution mechanism between Pb 2+ and the metal–organic framework – Cu‐MOF‐74. Pb 2+ can specifically substitute Cu active sites in Cu‐MOF‐74 and released Cu sites, strongly amplifying the CL emission of the luminol‐hydrogen peroxide (H 2 O 2 ) system. A linear response for Pb 2+ 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 Pb 2+ determination in water samples. It offers a new strategy to design high selective and sensitive sensors for the heavy metal ions monitoring.