Carbon Dots and Eu3+ Hybrid-Based Ratiometric Fluorescent Probe for Oxytetracycline Detection

Overuse of oxytetracycline (OTC) in livestock farming cancause environmental water pollution, risking human health. It is essential toexploit efficient, fast, and sensitive measures to sense OTC inenvironmental water samples. In this study, a ratiometricfluorescenceprobe consisted of blue-fluorescent carbon dots (CDs) and Eu3+wasconstructed to detect OTC sensitively and selectively. Upon the additionof OTC, bright redfluorescence was generated due to the aggregation ofEu3+, and the intensity of bluefluorescence of CDs reduced because of theinnerfilter effect between OTC and CDs. Under 365 nm UV lightirradiation, the increasing of OTC concentration from 0 to 10 mu M resulteda transformation of probe solutionfluorescence color from blue to pick.This CDs-Eu3+hybrid probe also performed a high selectivity for OTCwith minimal interference containing various antibiotics, cations, andamino acids. Importantly, the probe demonstrated a low detection limit of 9.6 nM and a satisfactory recovery efficiency for OTCdetection in river and tap water