Fluorescent sensing of nitrite at nanomolar level using functionalized mesoporous silica

Aminopyrene was covalently anchored onto mesoporous silica through serial post-grafting to obtain a fluorescent solid that can be used as a sensing material for the determination of nitrite. The latter, in acidic medium, reacts with the secondary amino groups on the material to form a non-fluorescent nitroso derivative. Based on the fluorescence quenching caused by this specific reaction, a method was developed for the determination of nitrite at nanomolar levels. The range for detection of nitrite in 1.5 mol.L −1 HCl is linear between 1.50 nM to 0.45 μM and 0.45 μM to 2.22 μM, the detection limit being 1.10 nM and 0.307 μM respectively at an S/N of 3. Figure Fluorescence quenching of aminopyrene-functionalized mesoporous silica when exposed to different concentrations of NO 2 −