Amine-capped carbon dots as a nanosensor for sensitive and selective detection of picric acid in aqueous solution via electrostatic interaction

In this study, a simple and low toxicity method based on water-soluble amine-capped carbon dots as a nanosensor for sensitive and selective detection of picric acid (PA) in water was developed. We found that PA could remarkably quench the fluorescence signal of the amine-capped carbon dots in water, while other nitroaromatic explosives and common reagents only caused little fluorescence quenching. The detection limit of the amine-capped carbon dots towards PA in aqueous solution was about 1 μM. The results indicate that the strong electrostatic interaction from an anion–cation pair between PA and the carbon dot surface could enhance the fluorescence selective response towards PA in aqueous solution.