“The relevant research team has made new progress in the field of fluorescence detection. Researchers have successfully synthesized copper/nitrogen co doped carbon quantum dots (Cu/N-CQDs) using a one-step hydrothermal synthesis method, and their fluorescence quantum yield has significantly increased to 30%. Research has found that the drug sulfasalazine (SSZ) can effectively quench the strong fluorescence properties of Cu/N-CQDs and exhibit a good linear response within the concentration range of 0.5-45 μ mol/L, with a detection limit as low as 1.7 nmol/L. The detection mechanism may be based on the static quenching process generated by the formation of non luminescent complexes between SSZ molecules and Cu/N-CQDs. The method was applied to the determination of SSZ content in commercially available SSZ tablets, and recovery experiments were conducted on SSZ in samples and serum. The recovery rate reached 95.13% to 103.2%, with a relative standard deviation of less than 5%, indicating that the method is accurate, sensitive, and selective.”