Oxidant-assisted preparation of carbon dots pairs for construction of a dual-channel fluorescence sensor array for tetracyclines discrimination

Abstract

The improper or excessive use of tetracyclines (TCs) can lead to residues in the environment and food, posing a global environmental concern. It is imperative to explore simple and economical methods for detecting and discriminating multiple TCs simultaneously. In this work, oxidant-doping carbon dots (OCDs) and reference carbon dots without oxidant-doping (RCDs) were synthesized in the presence and absence of ammonium persulphate (APS), resulting in distinct compositions of functional groups. TCs can quench the fluorescence of the two CDs to different extents, thus a two-channel fluorescence sensor array for five kinds of TCs was constructed. The discrepancies in fluorescence response of the two CDs towards various TCs were maximized through regulating the spiked concentration of APS. Under optimal sensing conditions, each of the five TCs produced unique fluorescence response patterns, allowing for differentiation within concentration ranges of 0.5 ∼ 50 μg mL⁻¹ based on linear discriminant analysis. Discrimination of binary, ternary and quaternary mixtures of TCs was achieved through the sensor array. The sensor array was successfully applied to tap water, lake water, and milk samples, yielding satisfactory recovery rates ranging from 85.1 % to 114.4 %. Additionally, molecular docking was initially employed to investigate the interaction modes and strengths between different TCs and the CDs. Overall, this study provides a viable detection platform for multiple TCs, demonstrating significant potential for environmental monitoring and food quality control.