Sulfur quantum dots as a novel platform to design a sensitive chemiluminescence probe and its application for Pb²⁺...

The monitoring of Pb as a hazardous heavy metal element for the environment and human health is of high importance. In this study, a simple and sensitive chemiluminescence (CL) probe based on sulfur quantum dots (SQDs) was designed for the determination of Pb²⁺ . To the best of our knowledge, this is the first report on the analytical application of the CL method based on SQDs. For this purpose, SQDs were synthesized using a simple hydrothermal method and characterized using transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. Then, the direct CL of SQDs elicited by common oxidants was investigated. The highest CL intensity was observed for the SQDs-KMnO₄ reaction, and its CL mechanism was studied. We indicated that the CL intensity of introduced system can be diminished as a result of the interaction between Pb²⁺ and SQDs, and exploited this fact for designing a CL-based probe for the determination of Pb²⁺ . The CL intensity of the SQDs-KMnO₄ reaction was linearly quenched using Pb²⁺ in the range 50-2000 nM with a limit of detection of 16 nM (S/N = 3). The probe was used for the determination of Pb²⁺ in different water samples and the recovery results (95.2-102.8%) indicated the good analytical performance of the developed method.