- A colorimetric and fluorescent dual probe for specific detection of cysteine based on intramolecular nucleophilic aromatic substitution.
A colorimetric and fluorescent dual probe for specific detection of cysteine based on intramolecular nucleophilic aromatic substitution.
The Analyst (2012-09-13)
Limin Ma, Junhong Qian, Haiyu Tian, Minbo Lan, Weibing Zhang
PMID22970425
RÉSUMÉ
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.