title: Cu2+-modulated cysteamine-capped CdS quantum dots as a turn-on fluorescence sensor for cyanide recognition.
abstract: A new fluorescence sensor for detection of cyanide ions (CN(-)) in aqueous media based on the recovered fluorescence of cysteamine capped CdS quantum dots [Cys-CdS QDs]-Cu(2+) system was proposed. The fluorescence intensity of Cys-CdS QDs was quenched by Cu(2+) due to the binding of Cu(2+) to cysteamine on the surface of the QDs. The degree of fluorescence quenching was proportional to the concentration of Cu(2+). However, in the presence of CN(-), the fluorescence intensity of Cys-CdS QDs was found to be efficiently recovered. Experimental results showed that the pH of the buffer solution and the concentration of Cu(2+) affected the fluorescence intensity upon adding CN(-). Under the optimal condition, the recovered fluorescence intensity was linearly proportional to the increasing CN(-) concentration in the range 2.5-20 μM. The limit of detection and the limit of quantification were found to be 1.13 μM and 3.23 μM, respectively. In addition, among the tested ions, only CN(-) could turn on the fluorescence intensity suggesting that the [Cys-CdS QDs]-Cu(2+) system was a highly selective sensor for CN(-). Moreover, this proposed sensor was demonstrated to detect CN(-) in drinking water with satisfactory results.
authors.affiliation: Materials Chemistry Research Unit, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Tuanjai
authors.initials: T
authors.lastname: Noipa
authors.forename: Thawatchai
authors.initials: T
authors.lastname: Tuntulani
authors.forename: Wittaya
authors.initials: W
authors.lastname: Ngeontae
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D003486:Cyanides / Q000032:analysis* / Q000737:chemistry; D003543:Cysteamine / Q000737:chemistry*; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D046529:Microscopy, Electron, Transmission; D045663:Quantum Dots; D013440:Sulfides / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D003486:Cyanides; D013440:Sulfides; C034939:cadmium sulfide; D003543:Cysteamine; D003300:Copper