Bithiophene-based fluorescent sensor for highly sensitive and ultrarapid detection of Hg in water, seafood, urine and live cells.

Using Hg-promoted deprotection reaction, we have developed a new fluorescent turn-on sensor 2TS based on bithiophene fluorophore for Hg detection. The sensing mechanism of 2TS towards Hg was strongly proved by H NMR, FTIR, HRMS, UV-vis and fluorescence spectra. Remarkly, 2TS towards Hg in 100% aqueous solution shows high sensitivity with a low detection limit of 19 nM, superior selectivity and ultra-rapid response of 20 s during a wide sensing pH range from 4 to 10. Taking advantage of the excellent properties, the low-cost sensor 2TS-based filter paper/TLC test strips were fabricated for visual, immediate and quantitative detection of Hg in water, proving its applicability towards sensitive in-situ and on-site detection. Meanwhile, 2TS showed high analytical performance for Hg detection in water, seafood as well as human urine samples. Moreover, thanks to the good water solubility, negligible cytotoxicity, good biocompatibility and cell-membrane permeability, 2TS was further applied to effectively image Hg in live cells. Furthermore, the developed sensor 2TS acted as good fluorescent display material for Hg with obvious color change.