title: Separation/preconcentration and determination of cadmium ions by solidification of floating organic drop microextraction and FI-AAS.
abstract: A simple and selective method for the separation and preconcentration of cadmium in water samples based on solidified floating organic drop microextraction (SFODME) was developed. The cadmium ion in aqueous solution was converted to CdI(4)(2-) and was then extracted with 160 microL of 1-undecanol containing cationic surfactant of methyltrioctylammonium chloride (0.2 mol/L). When the extraction was completed, the sample vial was cooled in an ice bath for 5 min. The solidified extract was transferred into a conical vial where it melted immediately. It was then diluted to 250 microL upon addition of ethanol, and 100 microL of it was analyzed by flow injection flame atomic absorption spectrometry (FI-FAAS). Factors that influence the extraction and ion pair formation, such as pH, concentration of iodide and methyltrioctylammonium chloride, extraction time, sample volume, and ionic strength were optimized. Under the optimized conditions, a preconcentration factor of 640, detection limit of 0.0079 microg/L and good relative standard deviation of +/-5.4% at 5 microg/L were obtained. The procedure was applied to tap water, well water, and sea water; and accuracy was assessed through recovery experiment and independent analysis by graphite atomic absorption spectrometry. The accuracy was also evaluated through analyses of certified reference ore.
authors.affiliation: Department of Chemistry, Faculty of Sciences, Yazd University, Safaeieh, 89195-741, Yazd, Iran. sdadfarnia@yazduni.ac.ir
authors.forename: Shayessteh
authors.initials: S
authors.lastname: Dadfarnia
authors.forename: Ali Mohammad Haji
authors.initials: AM
authors.lastname: Shabani
authors.forename: Elahe
authors.initials: E
authors.lastname: Kamranzadeh
mesh_terms: D000042:Absorption; D053000:Analytic Sample Preparation Methods / Q000379:methods*; D002104:Cadmium / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification*; D019187:Cadmium Compounds / Q000737:chemistry; D017022:Flow Injection Analysis; D006863:Hydrogen-Ion Concentration; D007454:Iodides / Q000737:chemistry; D009930:Organic Chemicals / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D052617:Solid Phase Microextraction / Q000379:methods*; D012997:Solvents / Q000737:chemistry; D013054:Spectrophotometry, Atomic; D013997:Time Factors; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D019187:Cadmium Compounds; D007454:Iodides; D009930:Organic Chemicals; D000644:Quaternary Ammonium Compounds; D012997:Solvents; D014874:Water Pollutants, Chemical; D002104:Cadmium; D014867:Water; C073250:cadmium iodide; C037759:trioctylmethylammonium