A carbon dots-based fluorescent probe for turn-on sensing of ampicillin

Carbon dots (CDs) with blue fluorescence were synthesized through hydrothermal treatment of p-dihydroxybenzene and hydrazine hydrate. The fluorescence of the investigated CDs could be selectively quenched by iron ions (Fe3+) because of the strong metal-ligand coordination and electrostatic interactions between the large amount of hydroxyl, amino, and carboxyl groups on CDs’ surface and Fe3+. Interestingly, this non-fluorescent CDs + Fe3+ complex displayed a sensitive and selective turn-on fluorescence toward ampicillin with a limit of detection of 0.70 μM. The sensing process could be observed by naked eyes under the 365 nm UV light irradiation. Importantly, CDs + Fe3+ complex had been successfully applied in the detection of ampicillin in river water.