title: Selective cloud point extraction for the determination of cadmium in food samples by flame atomic absorption spectrometry.
abstract: A new cloud point extraction (CPE) procedure for preconcentration of cadmium prior to the determination by flame atomic absorption spectrometry (FAAS) was developed. The method is based on the fact that cadmium could form hydrophobic ion-associated complex in the presence of iodide and methyl green (MG), and the hydrophobic ion-associated complex could be extracted into surfactant-rich phase. The main factors affecting CPE procedure, such as pH, concentration of KI, MG and surfactant, equilibrium temperature and incubation time, sample volume were investigated. Potential interference from co-existing ions was largely eliminated as most of co-existing ions can not form extractable ion-associated complex with iodide and MG. Under the optimum conditions, the limit of detection (3σ) and limit of quantity (10σ) were 0.90ngmL(-1) and 3.0ngmL(-1) for cadmium, respectively, and relative standard deviation was 4.2% (c=50ngmL(-1), n=7). The proposed method was successfully applied to determination of cadmium in the certified reference rice sample (GBW08510) and food samples with satisfactory results.
authors.affiliation: School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, PR China. Electronic address: xianggq@126.com.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Xiang
authors.affiliation: School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, PR China.
authors.forename: Shengping
authors.initials: S
authors.lastname: Wen
authors.affiliation: School of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, PR China.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Wu
authors.affiliation: School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, PR China.
authors.forename: Xiuming
authors.initials: X
authors.lastname: Jiang
authors.affiliation: School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, PR China.
authors.forename: Lijun
authors.initials: L
authors.lastname: He
authors.affiliation: School of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, PR China.
authors.forename: Yulan
authors.initials: Y
authors.lastname: Liu
mesh_terms: D002104:Cadmium / Q000032:analysis / Q000737:chemistry*; D063427:Food Quality; D013054:Spectrophotometry, Atomic / Q000379:methods*; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D013501:Surface-Active Agents; D002104:Cadmium
keywords: Atomic absorption spectrometry; Cadmium; Cloud point extraction; Food samples; Ion-associated complex