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A squaraine and Hg(2+)-based colorimetric and "turn on" fluorescent probe for cysteine
Qian Lin1, Yangwei Huang, Juan Fan
1Key Laboratory of Analysis and Detection for Food Safety, Ministry of Education, and Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, PR China.
Abstract:
A novel squaraine derivative (SQ-1) was synthesized and characterized for the determination of cysteine. Binding with Hg(2+) as a fluorescent quencher to SQ-1 leads to absorption and emission turn-off. More significantly, the SQ-1-Hg(2+) complex exhibits a dual-channel chromofluorogenic responses to biologically important cysteine with a high sensitivity and selectivity over other natural amino acids, along with a low detection limit of 36.7 nM.

