Sulfur quantum dots as a novel platform to design a sensitive chemiluminescence probe and its application for Pb 2+ 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 chemilumi-
nescence (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 transmis-
sion electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelec-
tron 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–KMnO 4 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 Pb 2+. The CL intensity of the SQDs–KMnO4 reaction was line-
arly quenched using Pb 2+ 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 Pb 2+ in different
water samples and the recovery results (95.2–102.8%) indicated the good analytical
performance of the developed method.