Collaborative compounding of metal-organic frameworks and lanthanide coordination polymers for ratiometric visual detection of tetracycline

Abstract In current study, a ratiometric fluorescence sensor (FSS@MOF-5/GMP-Eu) based on self-assembly of Eu3+ and guanosine monophosphate (GMP) on the surface of fluorescein loaded MOF-5 (FSS@MOF-5) is designed and fabricated for visual detection of tetracycline (TC). As the TC recognizer, Eu3+ specifically reacts with TC to form EuTC complex and results in fluorescence enhancement due to the antenna effect. With the TC addition, visible fluorescence changes from yellowish-green to orange and finally to red can be easily observed by naked eyes. The proposed FSS@MOF-5/GMP-Eu displays an excellent linear relationship with TC (0–20 μM), providing a low detection limit of 18.5 nM. The ratiometric sensor exhibits excellent selectivity to TC against other interferents owing to the formation of EuTC complex. The prepared FSS@MOF-5/GMP-Eu can be employed for TC detection in milk and pork and will also be valuable for use in fluorescence sensor applications.