Immobilization of a non-aqueous soluble probe onto mesoporous silica for utilization in highly sensitive and selective detection and removal of Hg~(2+) in pure aqueous media

摘要

An efficient strategy to immobilize a non-aqueous soluble Hg~(2+) probe onto mesoporous silica is developed, and this immobilization is subject to several advantages regarding Hg~(2+) detection, such as improving sensing sensitivity and selectivity, extending application from an organic/aqueous mixture to a pure aqueous medium, and achieving removal of Hg~(2+) ions while detection. The selected Hg~(2+) probe, rhodamine B thiohydrazide, can be readily covalently immobilized onto mesoporous silica through a simple amide reaction and subsequently exhibits more than 10 times enhancement of sensitivity for Hg~(2+) (limits of detection are of 0.81 ppb in immobilized form versus 10 ppb in free form), and an adsorption capacity of 192 mg/g. Brunauer—Emmett—Teller and TEM characterizations demonstrate that the mesoporous structure can be well remained after Hg~(2+) probe modification and this feature is believed to be responsible for improved Hg~(2+) sensing properties.