Here, a simple and portable paper-based analytical device (PAD) based on the inherent capability of carbon quantum dots (CQDs) to serve as a great emitter for the bis(2,4,6-trichlorophenyl)oxalate (TCPO)-hydrogen peroxide (H₂O₂) chemiluminescence (CL) reaction is introduced for the detection of harmful mercury ions (Hg2+ ). The energy is transferred from the unstable reaction intermediate (1,2-dioxetanedione) to CQDs, as acceptors, and an intensive orange-red CL emission is generated at ~600 nm, which is equal to the fluorescence emission wavelength of CQDs. The analytical applicability of this system was examined for the determination of Hg2+ . It was observed that Hg2+ could significantly quench the produced emission, which can be attributed to the formation of a stable and nonluminescent Hg2+ -CQDs complex. Accordingly, a simple and rapid PAD was established for monitoring Hg2+ , with a limit of detection of 0.04 μg ml-1 . No interfering effect on the signal was found from other examined cations, indicating the acceptable specificity of the method. The designed assay was appropriately utilized to detect Hg2+ ions in cosmetic samples with high efficiency. It was characterized by its low cost, ease of use, and was facile but accurate and high selective for the detection of Hg2+ ions. In addition, the portability of this probe makes it suitable for on-site screening purposes.
Keywords: carbon quantum dots; chemiluminescence; mercury ion; paper-based analytical device.
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