Dual-Emission Fluorescent Probe for the Simultaneous Detection of Nitrite and Mercury(II) in Environmental Water Samples Based on the Tb-Modified Carbon Quantum Dot/3-Aminophenylboronic Acid Hybrid.

Nitrite (NO) and mercury (Hg) ions are recognized as two typical inorganic contaminations that can cause severe damage to the environment and humans. In this paper, the energy transfer from carbon quantum dots (CQDs) to Tb by the antenna effect was found, which can promote the f-f transition of Tb and emit strong characteristic fluorescence of Tb. Based on CQD-Tb and 3-aminophenylboronic acid (APBA), which have respectively sensitive and specific fluorescent response to NO and Hg with different fluorescent signals, a dual-emission fluorescent probe of the CQD-Tb/APBA hybrid was thus fabricated for the simultaneous detection of NO and Hg in environmental water samples. They emit dual-emission fluorescence peaks centered at 373 and 545 nm, respectively. A good linearity between the quenching efficiency of ( - )/ and the concentrations of NO and Hg was in the range of 5.0-1200.0 nM for NO and 0.1-6.0 μM for Hg. The limit of detection (LOD, 3σ/K) is ultrasensitive for NO (2.0 nM), and the LOD for Hg is 38.1 nM. The dual-emission fluorescent probe was successfully applied for the determination of NO and Hg in various environmental water samples. The possible luminescence and fluorescence quenching mechanisms of the probe are also discussed in detail. This study provides a new approach for fabricating a multifunctional fluorescent probe or sensor and a prospective application in environmental monitoring.