Dual photoluminescence emission carbon dots for ratiometric optical dual-mode and smartphone-integrated visual detection of mercury ion

Development of detection platforms having portable, easy-to-use, and cost-effective designs is essential for environmental monitoring as well as food safety inspection. Herein, we proposed a smartphone-based handheld sensing strategy integrated with nitrogen-doped carbon dots (NCDs) test strip by employing three-dimensional (3D) printing technology for visual detection of Hg2+. Using this handheld detection platform, the FL color of test strips varied from red to purple with the increase of Hg2+ concentration. A great linear response between the R/B value and Hg2+ concentration in the range of 0 mu M-125 mu M was shown, with a detection limit of 0.024 mu M. Further, the constructed platform was applied for quantitative detection of Hg2+ in real water samples. Inter-estingly, as-prepared NCDs allowed the monitoring of Hg2+ with the dual-signal ratiometric model. Finally, the NCDs were used to detect Hg2+ in biological systems with satisfactory results. This work will contribute to the new strategy to design easy-to-use and user-friendly devices for on-site quantitation of targets.

Automated summary

The development of portable, easy-to-use, and cost-effective detection platforms is crucial for environmental monitoring and food safety inspection. In this study, we proposed a smartphone-based handheld sensing strategy that integrates nitrogen-doped carbon dots (NCDs) test strip using three-dimensional (3D) printing technology for visual detection of Hg2+. The handheld detection platform showed a great linear response between the R/B value and Hg2+ concentration in the range of 0 μM-125 μM, with a detection limit of 0.024 μM. The platform was successfully applied for quantitative detection of Hg2+ in real water samples and biological systems.