Nitrogen-doped carbon dots as an effective fluorescence enhancing system for the determination of perfluorooctyl sulfonate.

Abstract

Nitrogen-doped carbon dots (NCDs) were synthesized via hydrothermal treatment of vitamin B1 and triethylamine. The NCDs exhibit strong blue fluorescence (with a peak at 437nm at an excitation wavelength of 370nm), good water solubility and excellent fluorescence stability in the pH3~12 range, at ionic strengths between 0.01 and 1M, and under UV illumination for 6h, as well as incubation temperature of 15~60°C. The nanoparticles respond selectively and sensitively to trace concentrations of perfluorooctane sulfonate (PFOS) through electrostatic interactions between PFOS and NCDs. This is accompanied by the aggregation of NCDs to yield enhanced fluorescence. The nanoprobe has high selectivity for PFOS even in presence of other common ions such as metal ions, anions, and structural analogues such as surfactants. Under the optimal conditions, the response is linear in the 0.3 to 160nM PFOS concentration range with a detection limit of 0.3nM. Satisfactory results were achieved for determination of PFOS in spiked real water samples. Graphical abstract Schematic presentation of the synthetic route to nitrogen-doped carbon dots (NCDs) starting from vitamin B1 and triethylamine, and its application for selective and sensitive fluorometric determination of perfluorooctane sulfonate (PFOS).