title: Separation and preconcentration of Ag(I) in aqueous samples by flotation as an ion-associate using iodide and ferroin followed the determination by flame atomic absorption spectrometry.
abstract: A simple method for separation/preconcentration and determination of Ag(I) in aqueous samples is described. The method is based on formation of an ion-associate between Ag(I)-iodide complex and ferroin, which can be floated at the interface of the aqueous/n-heptane phases. The flotation process was carried out using 500-ml aliquot of the aqueous solution and the floated layer was dissolved in 5 ml of 1 M HNO3 containing methanol (50% v/v) as the solvent. The Ag(I) content was then determined by flame atomic absorption spectrometry (FAAS). The method so could be considered as an enrichment process, was achieved to a quantitative feature, when the pH of the solution was adjusted to 4 and the concentrations of iodide and ferroin were about 3.2 x 10(-4) M and 6.25 x 10(-5) M, respectively. The LOD and RSD (n = 7) were obtained 1.0 x 10(-8) M and 2.4%, respectively. It was found that a large number of cations and anions even at high considerably foreign ion/Ag(I) ratios were not interfered. The method was applied satisfactorily to recovery of Ag(I) from different aqueous samples.
authors.affiliation: Department of Chemistry, Faculty of Science, Birjand University, Birjand, P.O. Box 79, Iran.
authors.forename: Mohammad Saeid
authors.initials: MS
authors.lastname: Hosseini
authors.forename: Hamid
authors.initials: H
authors.lastname: Hashemi-Moghaddam
authors.forename: Gholamreza
authors.initials: G
authors.lastname: Kardan-Moghaddam
mesh_terms: D007454:Iodides / Q000737:chemistry*; D010618:Phenanthrolines / Q000737:chemistry*; D012834:Silver / Q000032:analysis / Q000302:isolation & purification*; D013054:Spectrophotometry, Atomic / Q000379:methods*; D014867:Water