Repurposing of waste ammonium sulfate as S,N-doped carbon quantum dots: A sensitive and selective fluorescent probe for the determination of tetracycline

Background: Currently, many types of pharmaceuticals are used to treat disease and bacterial infections. Tetracycline (TC) is a widely applied human and veterinary medicine. However, the widespread usage and lack of awareness in the management of TC lead to its unavoidable discharge into the environment. The consequences include the proliferation of resistant strains of bacteria and adverse impacts on nontarget organisms and microbial ecosystems, which means that TC is an emerging substance of concern and that it is crucial to develop determination platforms with cost-effective and fast-response features. Methods: Carbon quantum dots (CQDs) have received tremendous attention owing to their great performance in fluorescent probing. In the present work, ammonium sulfate-doped carbon quantum dots (S,N-CQDs) are fabricated through a facile hydrothermal synthesis pathway. Significant Findings: The results illustrate that the S,N-CQDs exhibit sensitive determination ability toward tetracycline via a static quenching mechanism and possess several superior features, including a rapid response, good sensitivity and stability, broad linear detection range (1-100 mu M), and low LOD value (0.1203 mu M), when applied in the determination of TC. Additionally, the application of S,N-CQDs valorizes ammonium sulfate waste from semiconductor manufactory waste and has great potential in fluorescence sensing.