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

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.