A highly sensitive and selective fluorescent chemodosimeter for Hg2+ in neutral aqueous solution.

A fluorescent assay of Hg(2+) in neutral aqueous solution was developed using N-[p-(dimethylamino)benzamido]-N'-phenylthiourea (1). 1's fluorogenic chemodosimetric behaviors towards various metal ions were studied and a high sensitivity as well as selectivity was achieved for Hg(2+). It was because of a strongly fluorescent 1,3,4-oxadiazoles which was produced by the Hg(2+) promoted desulfurization reaction. The spectra of ESI mass and IR provided evidences for this reaction. According to fluorescence titration, a good linear relationship ranging from 1.0 x 10(-7) to 2.0 x 10(-5) mol l(-1) was obtained with the limit of detection as 3.1 x 10(-8) mol l(-1).