Electrochemiluminescence Enhancement for the High‐Sensitivity Detection of Chlortetracycline Based on the Metal Single‐Atom–Filled Metal–Organic Framework

ABSTRACT Signal amplification remains challenging while using electrochemiluminescence (ECL) for trace pollutant detection within environmental frameworks. This study presents a strategy for catalytically amplifying detection signals based on metal single‐atom encapsulation in metal–organic framework (MOF) materials. First, a zinc porphyrin‐based MOF (Zn‐TCPP) with an ECL signal is synthesized. Then Fe and Co single atoms (SAs) are encapsulated into Zn‐TCPP to construct a Zn‐TCPP@FeCo SAs polymetallic catalytic amplification system. On the glass carbon electrode modified with Zn‐TCPP@FeCo SAs, a molecular imprinted polymer (MIP) of chlorotetracycline is constructed by electropolymerization. An ECL sensor that specifically recognizes the target molecule is obtained after elution with chlorotetracycline. The ECL signal of Zn‐TCPC is significantly enhanced by FeCo SAs, which is quenched after re‐adsorption of chlorotetracycline. Hence, a novel technique to detect chlorotetracycline residues in the environment and aquatic products is presented. The Zn‐TCPP@FeCo SAs make the sensor highly sensitive to trace residues, and the MIP allows the sensor to specifically recognize chlorotetracycline. A linear detection range of 1–8000 × 10 −12 mol L −1 is achieved with a detection limit of 8.60 × 10 −13 mol L −1 for seawater samples.