Highly chemoselective turn-on fluorescent probe for ferrous (Fe) ion detection in cosmetics and live cells.

In modern society, the use of cosmetics has increased extensively; unfortunately, so-called several toxic metal salts are present as the colorant or filler in cosmetics. The ferrous ion (Fe) is one of the metal ions used in cosmetics as a colorant. Ferrous ion (Fe) is a vital component in live cells. Considering the adverse effect of high doses of ferrous ions in cosmetics and live cells, we developed a turn-on fluorescent probe P for quantitative estimation of ferrous ion (Fe) in cosmetics and monitoring of labile ferrous (Fe) ion in live cells. The fluorescent probe P showed a visual color change from colorless to orange in the presence of ferrous ion (Fe) in the cosmetics. We observed that UV-absorption increased at 390 nm upon incubation with ferrous ion (Fe). The probe P has provided quantitative information on ferrous ion (Fe) in various cosmetics, kajol, lip balm, face foundation, mascara, eyeliner, lipliner, face makeup, sindoor, lipstick, nail polish in ppm level through the fluorescence signaling at 460 nm.The probe P provided information on labile Fe ion pool via a fluorescence imaging. It is a new addition to the diagnostic inventory for detecting ferrous ion in live cells and cosmetics.