Fluorescent mesoporous silica nanoparticles functionalized graphene oxide: A facile FRET-based ratiometric probe for Hg2+

This paper reported a facile method for fabricating a functionalized fluorescent graphene oxide (GO) by covalently grafting the amine-modified mesoporous silica nanoparticles (MSNs) containing poly(p-phenylenevinylene) (PPV) and lactam of Rhodamine 6G (SRh6G) inside the channel of MSNs. The resulted GO-PPV@MSN-NH 2 @SRh6G fluorescent hybrid nanoparticles had a good dispersion and strong green fluorescence in aqueous solution. This hybrid material can be used as a fluorescent ratiometric probe to detect Hg 2+ in the water through fluorescence resonance energy transfer (FRET). Upon the addition of only Hg 2+ ions, the mission corresponding to the ring-opened form of rhodamine appeared at 550   nm with a simultaneous emission quenching of PPV at 494   nm. This ratiometric fluorescence change indicated that an FRET from the PPV to rhodamine was triggered by Hg 2+ ions. The hybrid nanoparticles of GO-PPV@MSN-NH 2 @SRh6G could be used as a novel fluorescent probe to carry out the quantitative detection of Hg 2+ with a detection limit of 7.1   ×   10 −8   M.