Facile preparation of mesoporous silica coated nitrogen doped carbon dots for sensitive detection of picric acid

In this work, a nanocomposite suitable for long-term storage was constructed for efficient and highly selective detection of picric acid (PA). For this purpose, nitrogen-doped carbon dots (N-CDs) were synthesized by a simple hydrothermal reaction one-step method, and the synthesized nitrogen-doped carbon dots were loaded into amine-modified mesoporous silica nanoparticles (MSN-NH2) to form N-CDs@MSN-NH2 nanocomposites. The as-synthesized N-CDs@MSN-NH2 was detected by X-ray photoelectron spectroscopy (XPS) and the Fourier transform infrared (FT-IR) analysis methods. After being coated with MSNs, the as-synthesized N-CDs@MSN-NH2 exhibits excellent photo-stability in storage for 60 days at room temperature. Furthermore, PA can significantly quench the fluorescence signal of N-CDs@MSN-NH2 through the fluorescence resonance energy transfer (FRET) effect, while other metal ions and nitro compounds only cause little change. The a-synthesized composites were used to detect PA with a detection limit of 50 nM in an aqueous solution. These results indicate that the synthesized composites have promise for application in PA detection in aqueous solution.