Central European Journal of Chemistry * E-mail: ashokrollahi@mail.yu.ac.ir Combination of cloud point extraction and fame atomic absorption spectrometry for preconcentration and determination of trace iron in environmental and biological samples Received 10 February 2008; Accepted 26 March 2008 Abstract: In the presented work, the conditions for cloud point extraction of iron from aqueous solutions using 7-iodo-8-hydroxyquinolin-5- sulphonic acid (Ferron) was investigated and optimized. The procedure is based on the separation of its ferron complex into the micel- lar media by adding the surfactant Triton X-114. After phase separation, the surfactant-rich phase was dissolved with 1.0 M HNO 3 in methanol. Iron was determined by fame atomic absorption spectrometry. Optimization of the pH, ligand and surfactant quantities, incubation time, temperature, viscosity, sample volume, and interfering ions were investigated. The effects of the matrix ions were also examined. The detection limits for three times the standard deviations of the blank for iron was 0.4 ng m L -1 , enrichment factor of 19.6 and preconcentration factor of 30 could be achieved. The validity of cloud point extraction was checked by employing real samples including soil, blood, spinach, milk, meat, liver and orange juice samples using the standard addition method, which gave satisfactory results. © Versita Warsaw and Springer-Verlag Berlin Heidelberg. Keywords: 7-iodo-8-hydroxyquinolin-5-sulphonic acid (Ferron) • Iron • Cloud point extraction • Triton X-114 • Flame atomic absorption spectrometry 1 Chemistry Department, Yasouj University, Yasouj, Iran 2 Chemistry Department, University of Erciyes, 38039 Kayseri, Turkey Mehrorang Ghaedi 1 , Ardeshir Shokrollahi 1* , Raziyeh Mehrnoosh 1 , Omid Hossaini 1 , Mustafa Soylak 2 Research Article Abbreviation TAN and Phen - tannins and other phenolic compound, PMBP - 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone, GF-AAS - graphite furnace atomic absorption spectrometry, FAAS - fame atomic absorption spectrometry. 1. Introduction It is widely accepted that the presence of Fe(III), alone or in combination has benefcial or deleterious effects on the properties of many substances and the nature of various biological systems. It provides a fundamental structure of hemoglobin, myoglobin, hem-enzymes and many co-factors involved in enzyme activities. Trace amounts of Fe(III) in various substances may be vital and can promote rancidity. It plays a central role in the biosphere and serves as the active center of proteins responsible for O 2 transport and electron transfer mechanisms and of metallo-enzymes such as oxidases, reductases, and dehydrases [1]. Fe(III) may control the mobility and toxicity of other metals, whilst Fe(III) may also be a limited nutrient for phytoplankton growth in the open ocean [2,3], Fe(II) is probably the preferred nutrient [4-6]. The concentration of Fe 3+ . ions in biological fuids is usually found at trace level, requiring sensitive instrumental techniques. Frequently a pre-concentration step is required when a complex matrix has to be analyzed. Flame atomic absorption spectrometry (FAAS) Cent. Eur. J. Chem. • 6(3) • 2008 • 488–496 DOI: 10.2478/s11532-008-0049-9 488 Unauthenticated Download Date | 7/29/18 1:59 AM