Constructing an eco-friendly and ratiometric fluorescent sensor for highly efficient detection of mercury ion in...

Mercury ion (Hg²⁺) is a highly toxic and ubiquitous pollutant, whose effective detection has aroused widespread concern. A novel ratiometric fluorescent sensor has been designed to rapidly and efficiently detect Hg²⁺ based on blue/red carbon dots (CDs) with environmental friendliness. This sensor was well characterized via TEM, FTIR, XPS, UV-vis, and zeta potential analysis and displayed excellent fluorescence properties and stability. The fluorescence of blue CDs at 447 nm was significantly quenched with the addition of Hg²⁺ resulted from the static quenching, whereas that of red CDs at 650 nm remained invariable. A sensitive method for Hg²⁺ determination was constructed in the range of 0.05-7.0 nmol mL^-1 with optimal conditions, and the detection limit was down to 0.028 nmol mL^-1. Meanwhile, compared to other 17 metal ions, the ratiometric fluorescent sensor exhibited high selectivity for Hg²⁺. Furthermore, satisfied recoveries had also been obtained for measuring trace Hg²⁺ in practical environmental samples. This developed ratiometric fluorescent sensor provided a reliable, environmental-friendly, rapid, and efficient platform for the detection of Hg²⁺ in environmental applications.