title: Turn-off-on chemiluminescence determination of cyanide.
abstract: A flow injection chemiluminescence (FI-CL) method was developed for the determination of cyanide (CN(-) ) based on the recovered CL signal by Cu(2+) inhibiting a glutathione (GSH)-capped CdTe quantum dot (QD) and hydrogen peroxide system. In an alkaline medium, strong CL signals were observed from the reaction of CdTe QDs and H2O2 , and addition of Cu(2+) could cause significant CL inhibition of the CdTe QDs-H2O2 system. In the presence of CN(-) , Cu(2+) can be removed from the surface of CdTe QDs via the formation of particularly stable [Cu(CN)n ]((n-1)-) species, and the CL signal of the CdTe QDs-H2O2 system was efficiently recovered. Thus, the CL signals of CdTe QDs-H2O2 system were turned off and turned on by the addition of Cu(2+) and CN(-) , respectively. Further, the results showed that among the tested ions, only CN(-) could recover the CL signal, which suggested that the CdTe QDs-H2O2 -Cu(2+) CL system had highly selectivity for CN(-) . Under optimum conditions, the CL intensity and the concentration of CN(-) show a good linear relationship in the range 0.0-650.0 ng/mL (R(2)  = 0.9996). The limit of detection for CN(-) was 6.0 ng/mL (3σ). This method has been applied to detect CN(-) in river water and industrial wastewater with satisfactory results.
authors.affiliation: School of Chemistry and Material Science, Shanxi Normal University, Linfen, 041004, Shanxi, People's Republic of China.
authors.forename: Suqin
authors.initials: S
authors.lastname: Han
authors.forename: Jianbo
authors.initials: J
authors.lastname: Wang
authors.forename: Shize
authors.initials: S
authors.lastname: Jia
mesh_terms: D003486:Cyanides / Q000032:analysis*; D017022:Flow Injection Analysis / Q000295:instrumentation; D049449:Luminescence
chemical_list: D003486:Cyanides
keywords: CdTe quantum dots; chemiluminescence; cupric ion; cyanide ion; turn off-on