Determination of tetracycline by FRET fluorescence between chenpi carbon quantum dots and copper nanoparticles

This paper describes a new strategy based on fluorescence resonance energy transfer (FRET), in which the rapid synthesis of carbon quantum dots (CQDs) and copper nanoparticles (CuNPs) is used for the determination of tetracycline (TC). Therefore, in this paper, CQDs for fluorescence determination of TC were prepared by microwave heating using chenpi as a carbon source. The prepared CQDs showed good dispersion and uniform spherical shape under transmission electron microscope (TEM), with an average particle size of about 1.91 nm. Under ultraviolet (UV) irradiation, the CQDs emitted bright blue-green fluorescence with a strong fluorescence (> 1.6 × 10³ a.u.), and the fluorescence intensity did not change within one week. The emission wavelength of CQDs overlapped with the absorbance of CuNPs, and therefore, CuNPs could burst the fluorescence of CQDs by FRET mechanism. After incubation with TC, the fluorescence of CQDs was restored by the ligand reaction of CuNPs with TC. The assay showed good linearity for TC in the 1–100 nmol/L range, with a determination limit of 0.3554 nmol/L. This study demonstrated the potential of CQDs in antibiotic assays and provided a valuable method for monitoring TC levels.