Casein–Tb–Ti3C2 quantum dots ratiometric fluorescence probe for the detection of ciprofloxacin

The development of a rapid and sensitive method for the detection of ciprofloxacin is crucial to ensure human health and safeguard the ecological environment. The present study demonstrates the synthesis of water-stable ratiometric fluorescence probe casein–Tb–Ti ₃ C ₂ quantum dots (casein–Tb–Ti ₃ C ₂ QDs) for precise detection of ciprofloxacin, based on the principle that ciprofloxacin effectively coordinates with lanthanide metal to enhance the fluorescence signal. In this approach, the I ₅₄₃ to I ₄₄₀ ratio was utilized as an indicator for monitoring changes in ciprofloxacin concentration. The ratiometric fluorescence probe demonstrated excellent linearity across a concentration range of 2–800 µM and exhibited high sensitivity, achieving a detection limit of 1.81 µM for ciprofloxacin. Furthermore, the ratiometric fluorescence probe was successfully employed for the detection of ciprofloxacin in milk and pork samples, achieving recoveries that ranged from 71.23–102.22%. Due to the advantages of high sensitivity and favorable selectivity, the potential of utilizing the ratiometric fluorescence probe for practical applications in ciprofloxacin detection.