Novel fluorescent probe based on dicoumarin for rapid on-site detection of Hg2+ in loess

It is momentous to exploit rapid, specific and on-site detection methods for mercury ion (Hg2+) in loess, as the severe toxicity of Hg2+ and the fragile ecological environment of Loess Plateau. In this paper, a novel fluorescent probe DC-Hg (Dicoumarin-Hg) was synthesized by 3-hydroxybiscoumarin and phenyl thiochloroformate at room temperature. DC-Hg could exclusively combine with Hg2+ to ‘turn-on’ yellow fluorescence at 530 nm among various other metal ions. The relationship between the remarkable increase in intensity and concentration of Hg2+ was associated with photoinduced electron transfer (PET), which was founded by Job’s plot and 1H NMR. The limit detection of DC-Hg showed to 85.25 nM in aqueous medium, which could be applied to varying situations. For the loess samples, they were only extracted by hand-shake and filtration for quickly complete the treatment operation on site, and the results proved that DC-Hg could satisfactorily detect the Hg2+ in mercury pollution areas.