Analytical Sciences

Dopamine Functionalized S,N Co-doped Carbon Dots as a Fluorescent Sensor for the Selective Detection of Fe³⁺ and Fe²⁺ in Water

Siyu LEI,*,** Na CHANG,*,** Jimei ZHANG,*,** and Haitao WANG*,***

*State Key Laboratory of Separation Membranes and Membrane Processes, Tiangong University, Tianjin, 300387, People’s Republic of China
**School of Chemistry and Chemical Engineering, Tiangong University, Tianjin, 300387, People’s Republic of China
***School of Environmental Science and Engineering, Tiangong University, Tianjin, 300387, People’s Republic of China

In current work, novel functionalized carbon dots have been designed and synthesized by covalently linking dopamine to the surface of S,N co-doped carbon dots (DA-S,N-CDs) for the selective detection of Fe³⁺ and Fe²⁺ in water. The as-synthesized DA-S,N-CDs emit blue fluorescence peaked at 470 nm and exhibit excitation-dependent tunable emissions. The tolerance towards pH, salt, and UV irradiation of synthesized carbon dots reveals excellent stability. Upon exposure to Fe³⁺ or Fe²⁺, the fluorescence of DA-S,N-CDs was selectively quenched, while other competitive cations did not change significantly. Under the optimal experimental conditions, the fluorescence intensity of DA-S,N-CDs showed a good linear relationship with the concentrations of Fe³⁺ and Fe²⁺ (5 – 200 μM for Fe³⁺ and 5 – 300 μM for Fe²⁺), and the limit of detection was 2.86 and 2.06 μM, respectively. Furthermore, considering the excellent stability and anti-interference, DA-S,N-CDs have been successfully used for the detection of Fe³⁺ and Fe²⁺ in environmental water.

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