A rare multi-emission metal-organic complex fluorescent probe for direct oxytetracycline recognition.

A simple and effective metal-organic coordination polymer, EuIn@MOCPs, which enables the rapid and selective detection of oxytetracycline (OTC) among tetracycline antibiotics was successfully synthesized. Unlike the previously reported rare-earth-doped metal-organic complexes, this probe not only exhibits the common 617-nm characteristic peak in response to OTC but also uniquely generates uncommon peak shifts at 591 nm and 652 nm, allowing it to specifically recognize OTC among tetracycline antibiotics. We found that the response of the probe and OTC had a linear relationship with a detection limit as low as 42.3 nM within the 0-90-μM concentration range using multi-peak ratio fluorescence testing. Finally, the rich color change from blue to red in fluorescence makes this probe an excellent candidate for the development of high-performance visual fluorescent test strips. This achievement provides an effective approach for fluorescent probes to recognize structurally similar contaminants.