Fluorescence chemosensors based on functionalized SBA-15 for detection of Pb²⁺ in aqueous media

A highly ordered mesoporous silica material (SBA-15) functionalized with 5-(4-carboxy-phenylazo)-8-hydroxyquinoline (CPA-8-HQL) for use as a fluorescence chemosensor for Pb²⁺ detection has been reported in this study. XRD, TEM, FT-IR, UV-vis diffuse reflectance spectra and TGA were used to characterize the grafting process. The results proved that CPA-8-HQL was successfully anchored into the channel of SBA-15 and that the primary ordered mesoporous structure of SBA-15 was well preserved. A fluorescence spectrophotometer was utilized to investigate the sensing properties, and a highly fluorescent enhancement at 429 nm was observed in the presence of Pb²⁺. Measurements of the sensitivity parameters demonstrated that the obtained organic/inorganic hybrid possessed excellent sensitivity and selectivity to Pb²⁺ in aqueous media. The lowest limit of detection was 4.90 × 10^-7 mol L^-1 for Pb²⁺.