Long wavelength emission multicolor fluorescent carbon quantum dots for the detection of pH, amino acids, and metal ions

Carbon quantum dots are widely used in the field of analysis and detection due to their excellent optical properties. At present, many studies have focused on the preparation of multi-color fluorescent quantum dots by simple methods. Inspired by this, carbon quantum dots with green (G-CQDs) and yellow fluorescence (YN-CQDs) emission were prepared by hydrothermal method using PTCDA and urea as precursors. After characterizing their morphology, structure, and optical properties, fluorescent probes for different purposes were constructed according to their different fluorescence characteristics. Since green G-CQDs are sensitive to acidic environments, pH detection kits are developed. In addition, G-CQDs can also efficiently detect Asp. YN-CQDs are used to detect metal ions and can specifically detect Fe3+. Both of them were applied to the detection of actual samples, showing high efficiency and reliability. It provides a new idea for the multi-purpose detection of carbon quantum dot fluorescent probes.