Detection of oxytetracycline in milk using a novel carbon dots-based fluorescence probe via facile pyrolysis synthesis

Abstract Amphiphilic blue-fluorescence carbon dots (B-CDs) were synthesized via pyrolysis method with citric acid and oleamine as precursors. B-CDs are monodispersed in ethanol, toluene and ultrapure water with the average particle sizes of 3.33 nm, 2.05 nm and 4.12 nm, respectively. The maximum excitation and emission wavelengths of these B-CDs are located at 370 and 459 nm, respectively. The B-CDs have good optical properties with excellent photostability. The fluorescence quantum yield (QY) of the as-prepared CDs is as high as 30.17%. The fluorescence of B-CDs is quenched because of static quenching by oxytetracycline. A high selective and sensitive fluorescence probe for detecting oxytetracycline was constructed with a linear range of 1.52-27.60 µg/mL and the detection limit of 0.33 µg/mL. The B-CDs-based fluorescence probe can be applied to analyze oxytetracycline in milk; the recoveries and relative standard are satisfactory. Furthermore, the B-CDs were exploited for imaging of SH-SY5Y cells. The results demonstrated that as-synthesized CDs can serve as a cellular imaging reagent owing to rematkable bioimaging performance. This work provides a new strategy for the detection of oxytetracycline in food.