Highly sensitive fluorescence probe based on functional SBA-15 for selective detection of Hg2+ in aqueous media

Abstract

An inorganic–organic hybrid fluorescence chemosensor (R6G-SBA-15) was prepared by covalent immobilization of a Rhodamine 6G derivative within the channels of mesoporous silica material SBA-15viatriethoxysilane groups. The primary hexagonally ordered mesoporous structure of SBA-15 is preserved after the grafting procedure. R6G-SBA-15 features effectively chromogenical and fluorogenical responses with a broad pH span (2–10), excellent sensitivity to environmentally relevant mercury levels lower to ppb range. It also exhibits Hg²⁺-specificity over various competitive cations, including alkali and alkaliearth, the first-row transition metals as well as heavy metals such as Pb²⁺, Cd²⁺ and Ag⁺, etc. Additional experiments establish the well-fitted linearity function of the fluorescent intensity with the concentration of Hg²⁺ in aqueous solution, suggesting the possibility for real-time qualitative or quantitative detection of Hg²⁺ and the convenience for potential application in toxicology and environmental science.