Dual-lanthanide cyclodextrin-polyoxometalate fluorescent assembly for rapid and sensitive detection of ciprofloxacin.

Quick screening and in-situ detection of trace antibiotics in environmental samples is needed for better control and monitoring of antibiotics pollution. Herein, a novel dual-lanthanide (Tb3+ and Eu3+) cyclodextrin-polyoxometalate fluorescent assembly (CD-LnPOM) has been developed for ciprofloxacin (CIP) detection. The "ratiometric" fluorescence response of CD-LnPOM enables specific detection of CIP within 5 s over a wide concentration range (0–100 μM) with a detection limit of 0.266 nM. When CIP presents, cyclodextrin acts as a host and encapsulates CIP in the cavity through host-guest interaction, which enhances the antenna sensitization between Tb3+ and CIP. Meanwhile, due to the more robust coordination between CIP and Tb3+, CIP blocks the energy transfer from Tb3+ to Eu3+ and recovers the sensitization of Tb3+ by POM. Based on the developed CD-LnPOM probe, a portable sensing device based on digital image color analysis is successfully demonstrated for real river water and antibiotic sludge samples. The developed fluorescent probe enables rapid and in-situ detection of trace antibiotics, which offers a new method for antibiotics screening and monitoring. [Display omitted] • Ciprofloxacin detection within 5 s with a detection limit of 0.266 nM. • Dual-lanthanide cyclodextrin-polyoxometalate fluorescent probe. • Portable instrument with fluorescent color change for in-situ detection of antibiotics. • Antibiotics detection in river water and antibiotic sludge samples. [ABSTRACT FROM AUTHOR]