Amino-functionalized silica-encapsulated Mn/ZnS quantum dots for the room-temperature phosphorescence determination of graphene oxide in environmental water samples

Abstract

We developed a simple and sensitive room-temperature phosphorescence (RTP) method for the determination of graphene oxide (GO) in environmental water samples using amino-functionalized silica-encapsulated Mn/ZnS quantum dots (Mn/ZnS@SiO₂-NH₂) as a phosphorescent probe. The maximum phosphorescence excitation and emission wavelengths of the synthesized Mn/ZnS@SiO₂-NH₂ nanoparticles were 320 nm and 595 nm. The RTP intensity of the Mn/ZnS@SiO₂-NH₂ nanoparticles could be quenched in the presence of GO with a detection limit as low as 1.0 mg L⁻¹. Good linear correlations were obtained over the concentration range from 0 to 10.0 mg L⁻¹ with a correlation coefficient of 0.9987, and 10.0 to 25.0 mg L⁻¹ with a correlation coefficient of 0.9979. The phosphorescence quenching mechanism was also discussed. This method was successfully applied to the determination of GO in environmental water samples which allows more opportunities for its application in biological and environmental systems.