Cost-Effective and Selective Fluorescent Chemosensor (Pyr-NH@SiO 2 NPs) for Mercury Detection in Seawater.

The release of mercury into the environment has adverse effects on humans and aquatic species, even at very low concentrations. Pyrene and its derivatives have interesting fluorescence properties that can be utilized for mercury (Hg 2+ ) ion sensing. Herein, we reported the highly selective pyrene-functionalized silica nanoparticles (Pyr-NH@SiO 2 NPs) for chemosensing mercury (Hg 2+ ) ions in a seawater sample. The Pyr-NH@SiO 2 NPs were synthesized via a two-step protocol. First, a modified Stöber method was adopted to generate amino-functionalized silica nanoparticles (NH 2 @SiO 2 NPs). Second, 1-pyrenecarboxylic acid was coupled to NH 2 @SiO 2 NPs using a peptide coupling reaction. As-synthesized NH 2 @SiO 2 NPs and Pyr-NH@SiO 2 NPs were thoroughly investigated by 1 H-NMR, FTIR, XRD, FESEM, EDS, TGA, and BET surface area analysis. The fluorescent properties were examined in deionized water under UV-light illumination. Finally, the developed Pyr-NH@SiO 2 NPs were tested as a chemosensor for Hg 2+ ions detection in a broad concentration range (0-50 ppm) via photoluminescence (PL) spectroscopy. The chemosensor can selectively detect Hg 2+ ions in the presence of ubiquitous ions (Na + , K + , Ca 2+ , Mg 2+ , Ba 2+ , Ag + , and seawater samples). The quenching of fluorescence properties with Hg 2+ ions (LOD: 10 ppb) indicates that Pyr-NH@SiO 2 NPs can be effectively utilized as a promising chemosensor for mercury ion detection in seawater environments.