Carbon-dot-based colorimetric turn-on probe for selectively detecting thiophenols

A colorimetric turn-on probe was developed for the selective naked-eye determination of thiophenols by using yellow-emissive carbon dots (Y-CDs) as the colorimetric reporter and 2, 4-dinitrobenzenesulfonamide (DNBS) group as the recognition unit. The surfaces of Y-CDs were covalently coated with 2, 4-dinitrobenzenesulfonyl chloride to afford the 2, 4-dinitrobenzene- functionalized carbon dots ( CD-DNBS ) as a novel probe for detecting thiophenols. CD-DNBS was nearly colorless. Upon addition of thiophenol , the DNBS moiety of CD-DNBS could be readily cleaved via nucleophilic substitution reactions, leading to a dramatic increase in absorbance at 400 nm. The established detection probe displays a high selectivity towards thiophenol over biothiols and other biologically related species.