Composite molecularly imprinted ratiometric fluorescent sensor based on carbon dots and CdTe quantum dots for visual detection of ciprofloxacin in seawater

As a commonly used antibiotic, the residues of ciprofloxacin (CIP) enter the environment owing to its abuse and it is of great significance for environmental protection and human health to develop a fast and selective sensor for the determination of trace CIP. In this work, composite imprinted ratiometric fluorescent nanoparticles of CdTe/CQDs@SiO 2 @MIPs that can efficiently and rapidly detect ciprofloxacin (CIP) in seawater samples were synthesized by sol-gel method. The blue fluorescence of carbon quantum dots (CQDs) at 436 nm was the reference, and the orange yellow fluorescence of CdTe QDs at 547 nm was sensitive to CIP. The sensor showed satisfying linear relationship till to 20 μmol L −1  (R 2  = 0.9963) with limit of detection (LOD) of 0.09 μmol L −1 and recoveries of 96.2–103.1% in seawater. It was successfully applied to the detection of CIP in seawater after pretreatment by solid phase microextraction. The sensor exhibited a “green-blue” color change window visible to the naked eye under 365 nm UV light. This method provides a fluorescence imprinting strategy for the visualization and in situ detection of CIP in environmental water.