A novel fluorescent “off-on” sensor for selective detection of mercury based on perylene dye and gold nanoparticles

A novel fluorescent turn-on strategy based on perylene probe (PDI) and arginine functionalized gold nanoparticles (arg-AuNPs) for the sensing of mercury ions (Hg2+) has been developed. Due to the strong electrostatic and hydrophobic interactions as well as strong π-π stacking effect, the PDI probe could be adsorbed onto the surface of the nanoparticles, inducing the aggregation of the arg-AuNPs. Consequently, fluorescence peaks of PDI at 550 and 591 nm were quenched by arg-AuNPs through energy transfer (ET) process, which could be enhanced upon the addition of Hg2+. The presence of Hg2+ could prevent the ET process and thus recovered the fluorescence of PDI. A turn-on fluorescence signal was therefore detected. Our assay method shows very high sensitivity with a limit of detection of 0.6 nM, and remarkable selectivity against the common interference metal ions. This sensing method has also been successfully used for real sample analysis. The “off-on” fluorescent sensing method is fairly simple, fast, and inexpensive, and the fluorescence quenching mechanism of PDI induced by arg-AuNPs was expected to be utilized for more target sensing applications.