Ratiometric Luminescence Nanoprobe Based upon a Coumarin-Ligated Lanthanide/Nucleotide Coordination Polymer for the Determination of Ciprofloxacin

This study presents the development and application of a novel ratiometric fluorescent nanoprobe, Tb/AMP/Dye-P, for the selective and sensitive determination of ciprofloxacin (CIP). The nanoprobe consists of a coordination polymer incorporating terbium (Tb), adenosine monophosphate (AMP), and a specially synthesized coumarin derivative (Dye-P). Dye-P exhibits strong blue fluorescence with a peak at 428 nm. Upon binding with the target CIP, the emission of Tb³⁺ at 544 nm is significantly enhanced, while the emission from Dye-P remains unchanged. This differential response allows for ratiometric detection of CIP based on the fluorescence intensity ratio at the two wavelengths. Detailed analysis of the interaction shows that the probe is highly selective for CIP and can be used for real-time onsite analysis with a smartphone color recognition app. This research not only demonstrates the potential of Tb/AMP/Dye-P in pharmaceutical and milk samples but also highlights its extensive application prospects in environmental monitoring and food safety.