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  • 1 Ibaraki University Department of Environmental Sciences, Faculty of Science Mito 310-8512 Japan
  • | 2 Ibaraki University Department of Environmental Sciences, Faculty of Science Mito 310-8512 Japan
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Abstract  

Substoichiometric isotope dilution analysis for the determination of trace iron has been studied by using synergistic extraction of iron(III) with a substoichiometric amount of 4-isopropyltropolone (Hipt) in the presence of an excess of 3,5-dichlorophenol (DCP) in heptane. Optimum conditions for the substoichiometric extraction of iron(III) in g to sub-g levels were examined and the high selectivity for iron(III) toward various metal ions encountered in the analysis of biological materials was confirmed. The present method was applied to a biological reference material (NIES, CRM No.9, sargasso) without any pre-separation and was successfully evaluated. Furthermore, substoichiometric stable isotope dilution mass spectrometry using the present extraction method was also used with the above sample. Applicability and practicability was compared for both substoichiometric methods.