Zinc-doped carbon quantum dots-based ratiometric fluorescence probe for rapid, specific, and visual determination of tetracycline hydrochloride

In this work, a rapid, specific, and visual ratiometric fluorescence probe was constructed for tetracycline hydrochloride (TCH) determination based on zinc-doped carbon quantum dots (Zn-CDs). In the presence of TCH, the blue fluorescence at 440 nm originating from Zn-CDs was quenched, and the green fluorescence at 515 nm stemming from TCH was enhanced. The inner filter effect (IFE) and the chelation between Zn and tetracycline are the main mechanisms for the conversion of spectra. The spectrum and color change completed and stabilized within 1 min, indicating the possibility of real-time detection of TCH. The detection range for TCH is 0.1–50 μM, and the low detection limit is 61.1 nM. In addition, Zn-CDs-based test strips were successfully applied to direct visual identification of TCH in actual samples of river water and milk, indicating the possibility of their practical application.