One Pot Generation of Blue and Red Carbon Dots in One Binary Solvent System for Dual Channel Detection of Cr3+ and Pb2+ Based on Ion Imprinted Fluorescence Polymers

Blue and red dual channel dual emission carbon dots (DDCDs) were synthesized by a one-step hydrothermal method in water-formamide binary system using citric acid and ethylenediamine as precursors. Then, the as-prepared DDCDs were directly employed for preparation of ion imprinted fluorescence polymers without further separation. Since Cr³⁺ can only quench the fluorescence of blue CDs, while Pb²⁺ only quenches the fluorescence of red CDs, dual channel detection of Cr³⁺ and Pb²⁺ can be achieved simultaneously based on ion imprinted fluorescence polymers. Under optimized conditions, the quenching effect [(F₀ - F)/F₀] at 440 nm for the blue channel against the concentration of Cr³⁺ was linear from 0.1 to 6.0 μM, while that for the red channel at 580 nm against the concentration of Pb²⁺ was linear from 0.1 to 5.0 μM. The detection limits for Cr³⁺ and Pb²⁺ can reach 27 nM and 34 nM, respectively. Satisfied recoveries have also been obtained for detection of Cr³⁺ and Pb²⁺ in real water samples. The application of this dual channel detection method will greatly simplify the heavy metal ion detection process in complicated water environments.