No abstract

Sulfite and sulfide share several similarities in terms of chemical properties, such as nucleophilic and reducing reactivities. Therefore, they may disturb the detection of each other. In order to discriminate between these two kinds of sulfur-containing species, a new probe -N3 was developed, in which para-azidobenzenyl ketone was covalently incorporated to a coumarin fluorophore linked by a C=C double bond. Sulfite and sulfide can respectively react with the C=C double bond and the azido group to give different products, consequently, they can be differentially identified by UV-vis and fluorescence spectroscopy as well as by the naked eye. Selectivity and competition results reveal that -N3 is a good candidate for the detection of sulfide and sulfite. The bioimaging experiment demonstrates the potential of the -N3 probe for the differential imaging of sulfide and sulfite in living cells.

4-Nitro-1,8-naphthalic anhydride (NNA) was used to distinguish cysteine from homocysteine and other potentially interfering thiols through a novel sequential substitution mechanism. The discrimination involves a blue-fluorescent thioether formation via nucleophilic aromatic substitution of the nitro group by thiol, followed by a second intramolecular nucleophilic aromatic substitution of alkylthio with the amino group to give the green-fluorescent 4-amino derivative. NNA is highly selective towards Cys, and the detection limit of Cys by this method is 0.3 μM.

No abstract

No abstract