Quasi-solid hydrogel electrolyte/nitrogen dot-based electrochemiluminescence sensor for enrofloxacin detection in milk.

In this study, a novel quasi-solid hydrogel-based electrochemiluminescence (ECL) sensor was developed to detect enrofloxacin (ENR) in milk. First, nitrogen-rich quantum dots ((5-AT-co-CA)-N-dots) with high luminescence efficiency were synthesized and served cathodic ECL luminophores. Second, the P(AM-co-AMPS)-PEDOT:PSS (PAMES) hydrogel was prepared as a quasi-solid electrolyte. The hydrogel exhibited high ionic conductivity (52.5 mS cm-1), excellent adhesion properties, high transparency (83 %), and high water content (89 %). The ECL signal of (5-AT-co-CA)-N-dots was enhanced by 4.3 times in is PAMES hydrogel compared to the solution. The solventless sensing system based on quasi-solid hydrogel electrolyte addressed the limitations of leakage and instability of traditional liquid electrolytes, thereby improving the portability and environmental adaptability of the sensor. Furthermore, a molecularly imprinted sensing system was constructed to detect ENR based on the PAMES hydrogel. This novel ECL sensor significantly simplified the operations and expanded s potential sensing applications.