A ratiometric near-infrared fluorescent probe with a large Stokes shift for rapid and sensitive detection of hydrogen sulfide in food samples and imaging in biological system

Hydrogen sulfide (H 2 S) has multiple contributions to living organisms and is also linked to the freshness of most high-protein foodstuffs. Therefore, developing a highly sensitive technology for on-site detection of H 2 S is promising and crucial. In this paper, a novel ratiometric near-infrared fluorescent probe 1,1,3-trimethyl-2-(4-(5,5,7-trimethyl-4,5,6,7-tetrahydro-3 H -4,6-methanobenzo[ d ]imidazol-2-yl)styryl)− 1 H -benzo[ e ]indol-3-ium iodide ( TIBI ) was designed and synthesized from α -pinene derivative 4,6,6-trimethylbicyclo[3.1.1]heptane-2,3-dione for the specific detection of H 2 S. TIBI displayed several excellent merits during the detection of H 2 S including low detection limit (19.43 nM), short response time (50 s), and wide pH detection range (5 9). The emission wavelength of TIBI blue-shifted from 690 nm to 460 nm accompanying with the fluorescence color changed from red to blue at the presence of H 2 S, and its fluorescence intensity ratio (I 460 nm /I 690 nm ) enhanced up by 540 folds. The TIBI -loaded test strips could successfully achieved the real-time and convenient monitoring of H 2 S produced from food spoilage . Besides, probe TIBI could be also applied for imaging H 2 S level in living cells and zebrafish.