A new fluorescence off-on chemodosimeter for L-cysteine based on water-soluble polythiophene

A novel water-soluble cationic conjugated polymer, denoted as poly 2,5-[3-(1,1-dimethyl-4-piperidine methylene)thiophene] chloride ( PDPMT-Cl) was a novel fluorescent material. Fluorescence can be quenched by [AuCl4](-) effectively. On addition of L-cysteine (L-Cys) in [AuCl4](-)-PDPMT-Cl, fluorescence recovered. A new method to detect L-Cys was established successfully by designing a fluorescent off-on probe. The method showed good sensitivity and selectivity. Under optimized condition, the fluorescence intensity was linear to L-Cys concentration varying from 1.0 x 10(-8) M to 6.0 x 10(-5) M (gamma=0.9982). The detection limit (3 sigma) was 1.39 x 10(-10) M. The method was successfully used for the determination of L-Cys in human serum and compound amino acid injection. (c) 2013 Elsevier B.V. All rights reserved.