铁-乙酰丙酮络合双水相萃取火焰原子吸收光谱法测定铁

Flame atomic absorption spectrometric determination of iron by aqueous double-phase extraction based on iron-acetylacetone complex

研究了乙酰丙酮水溶液在乙酸和电解质作用下的相分离及其通过形成乙酰丙酮-Fe^3＋络合物实现对Fe^3＋的萃取。结果表明，Fe^3＋在弱酸性至弱碱性酸度范围内的萃取率随体系pH值及乙酰丙酮相体积的增大而增大，在Na3PO4存在下乙酰丙酮对Fe^3＋的萃取能力最强。提出了乙酰丙酮-冰乙酸-Na3PO4双水相萃取，火焰原子吸收光谱法（FAAS）测定铁的新方法。方法检出限为6．2μg／L，测定铁质量浓度的线性范围为10～120μg／L，铁的萃取率为96．1％～98．4％。用于自来水和井水中铁的测定，相对标准偏差为2．4％～3．8％。

The phase separation behaviors of acetylacetone in acetic acid, electrolytes systems and iron preconcentration based on the formation of iron-acetylacetome complex were investigated. The result showed that the extraction efficiency for iron increased with the increasing of pH value and acetylacetone volume in weak acid and base medium. In the presence sodium phosphate, the extraction efficiency of iron by acetylacetone was the greatest. Consequenely,a new method for determining iron was established by flame atomic absorption spectrometry combined with acetylacetone-acetic acid-sodium phosphate system. Linear calibration graph was obtained in the concentration range of 10--120 μg/L for iron ,with a detection limit of 6.2 μg/L. The extraction efficiency was in the range of 96.1% -- 98.4%. The method has been applied to the determination of tap water and weu water, with the relative standard deviation of 2.4 %- 3.8 %.