Acid red G stabilized blue fluorescent copper nanoclusters for the detection of tetracycline

In this paper, a novel copper nanoclusters (ARG-CuNCs) has been synthesized by Acid red G stabilized. The optimal excitation wavelength of the synthesized ARG-CuNCs is 330 nm, and a corresponding emission peak is 426 nm. Notably, the fluorescence intensity of ARG-CuNCs could be stablized over six months, and it exhibits minimal variation within the pH range of 2.21–11.58, indicating exceptional stability of the synthesized copper nanoclusters. It was observed that tetracycline (TC) effectively quenches the fluorescence intensity of ARG-CuNCs, and the relative fluorescence intensity change ( Q  = F 0 /F) exhibiting a linear relationship with the concentration of TC in the range of 1.0–110.0 µmol/L, and the detection limit (LOD) is 0.33 µmol/L. Thus, a fluorescence-based analytical method for determining TC concentration has been developed based on the relationship of the Q value with the concentration of TC. Furthermore, leveraging a smartphone and colorimetric analysis software, a novel visual quantitative detection method for TC detection has been established based on the image of the mixture solution (TC and ARG-CuNCs) under the 365 nm ultraviolet lamp irradiation, and using ARG-CuNCs as a fluorescence probe. Graphical abstract