title: A methionine-based turn-on chemical sensor for selectively monitoring Hg2+ ions in 100% aqueous solution.
abstract: Dansyl-labeled methionine is synthesized by solid-phase synthesis, and found to be a highly sensitive and selective sensor for Hg(2+). The sensor sensitively detects Hg(2+) ions in aqueous solution by a turn-on response; however, the sensor detects Hg(2+) ions by a turn-off response in organic and mixed aqueous-organic solutions. We investigated the binding stoichiometry, binding constant, and binding mode of the sensor under various solvent conditions. In 100% aqueous solution, 2 : 1 complexation of the sensor with Hg(2+) ions is more favorable than 1 : 1 complexation, whereas the sensor preferentially forms a 1 : 1 complex in 100% CH(3)CN or in 50% CH(3)CN-aqueous solutions. Results reveal that the stoichiometry of the sensor-Hg(2+) complex plays an important role in the type of response to Hg(2+) ions, and that 2 : 1 complexation is required for a turn-on response to Hg(2+) ions in aqueous solution.
authors.affiliation: Bioorganic Chemistry Lab, Department of Chemistry, Inha University, 253-Yunghyun-dong, Nam-gu, Incheon 402-751, South Korea.
authors.forename: Mi-Hwa
authors.initials: MH
authors.lastname: Yang
authors.forename: Chuda Raj
authors.initials: CR
authors.lastname: Lohani
authors.forename: Hyeongjin
authors.initials: H
authors.lastname: Cho
authors.forename: Keun-Hyeung
authors.initials: KH
authors.lastname: Lee
mesh_terms: D002413:Cations, Divalent / Q000737:chemistry; D005456:Fluorescent Dyes / Q000032:analysis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008628:Mercury / Q000032:analysis* / Q000737:chemistry; D008715:Methionine / Q000737:chemistry; D015394:Molecular Structure; D012996:Solutions / Q000737:chemistry; D012997:Solvents / Q000737:chemistry
chemical_list: D002413:Cations, Divalent; D005456:Fluorescent Dyes; D012996:Solutions; D012997:Solvents; D008715:Methionine; D008628:Mercury