A colorimetric and fluorescent dual probe for specific detection of cysteine based on intramolecular nucleophilic aromatic substitution.

摘要: 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 blue-fluorescent thioether formation via nucleophilic aromatic of the nitro group by thiol, followed second intramolecular alkylthio with amino give green-fluorescent 4-amino derivative. NNA is highly selective towards Cys, detection limit Cys this method 0.3 μM.