Gasoline residue-prepared carbon dots embedded metal–organic frameworks for selective and sensitive detection of sulfide ions

Sulfide ions (S2-) are well-known and hazardous pollutants that are commonly found in natural water and wastewater. Their excessive presence can lead to environmental problems and pose a risk to living systems and human health. Therefore, the development of affordable and accurate methods for detecting trace amounts of S2- has become a topic of great interest. This study presents a novel approach to constructing highly fluorescent carbon dots (CDs) using gasoline residue from combustion. The CDs were then embedded into a zeolitic imidazolate framework (ZIF-8) crystal at room temperature, resulting in the creation of a CDs@ZIF-8 nanoprobe for S2- detection. The sensing mechanism was based on the fact that the encapsulation of CDs into ZIF-8 can restrain its fluorescent emission, while fluorescence enhancement could be observed by adding S2- due to the S2- can react with the metal node (Zn2+) of ZIF-8 to release the CDs. The sensing platform achieved a low limit of detection (LOD) of 330 nM and a relative standard deviation (RSD, n = 7) of 0.7% under optimized conditions. The platform was successfully applied to quantify S2- in water and gasoline samples, indicating its potential for practical use. The method proposed in this study is rapid, direct, and sensitive for S2- assay with favorable experimental conditions.