Naphthoquinone-Functionalized Nanoporous Silica: Synthesis, Characterization and Application for Fluorescent Sensing of Dicromate

A naphthoquinone-functionalized hybrid organic-inorganic silica-based fluorescent sensor was designed, synthesized and characterized by X-ray diffraction, N-2 adsorption-desorption, thermogravimetric and infrared spectroscopy analysis. Fluorescence properties of the prepared sensor were investigated in the presence of different anions under excitation at 305 nm. The fluorescence emission of the sensor was remarkably quenched after addition of Cr2O72-. Selectivity of the sensor was studied in the presence of common competing metal ions. The obtained results revealed that the sensor had high selectivity toward Cr2O72- anion. The linear relationship between the concentration of target anion and the fluorescence intensity was proved by performing a titration experiment. Finally, the detection limit was calculated as 6 x 10(-6) M, which demonstrates high sensitivity of the sensor toward Cr2O72-.