Nitrogen and boron co-doped carbon dots probe for selectively detecting Hg2+ in water samples and the detection mechanism

Abstract

Mercury ions represent hazardous contaminants with significant adverse effects on human health, wildlife, and vegetation. Therefore, it is crucial to create a sensitive and trustworthy technique for identifying mercury ions. In this study, nitrogen and boron co-doped carbon dots (N,B-CDs) were created via a one-step hydrothermal approach, employing citric acid, polyethyleneimine, and boric as precursors. The resulting N,B-CDs exhibited spherical morphology with an average diameter of 2.60 nm and emitted blue fluorescence with peak emissions at 442 nm (λ em) upon excitation at 360 nm (λ ex), yielding a fluorescence quantum yield of 27.34%. Remarkably, N,B-CDs, without any surface modifications, functioned as a direct “turn-off” probe, enabling swift, highly selective Hg2+ detection. The N,B-CDs probe could measure Hg2+ in the linear ranges of 0.40–22 μM and 22–208 μM , with a detection limit of 0.12 μM. The detection mechanism was attributed to dynamic quenching interactions between N,B-CDs, and Hg2+. Additionally, the probe was used to detect Hg2+ in both tap and river water, and the recovery rates ranged from 87.20 to 108.20% (RSD <4.89%). These findings highlighted the method’s considerable practical potential for detecting Hg2+ in environmental water.

Keywords

• nitrogen and boron co-doped carbon dots
• detection of hg2+
• one-step hydrothermal approach
• dynamic quenching