Applycation of the synergistic extraction to separation analysis

研究了单硫代烯基三氟丙酮(STTA=HR)与1，10-邻菲咯啉(Phen)协同萃取Mn(II)和Fe(II)的机理，发现在氯仿相中的萃取物为MnR2(Phen)和Fe2(Phen)2，适用于Fe(II)和Mn(II)的定量分离。相反，Ni(Phen)_3^&lt；2+&gt；对STTA阴离子是惰性的。如果Co(Phen)_3^&lt；2+&gt；不稳定，则Co(II)优先被萃取，而Ni(Phen)_3^&lt；2+&gt；仍留在水相中。在此基础上，利用双硫腙-邻菲咯啉体系实现了Co(IIR)与Ni(II)的定量分离，在水相中初步加入邻菲咯啉以保证Ni(Phen)_3^&lt；2+&gt；的定量生成，并将协同萃取体系应用于痕量金属离子的预富集。结果表明，采用双硫腙-三丁基氧化膦萃取体系，原子吸收光谱法可测定天然河水中痕量Cd(II)。

Synergistic extraction mechanism of Mn(II) and Fe(II) with monothiothenoyltrifluoroacetone(STTA=HR) and 1,10-phenanthroline(phen) was studied, and it was found that the extraction species in chloroform phase were MnR_2(phen) and FeR_2(phen)_2. This extraction system was shown to be applicable to the quantitative separation of Fe(II) from Mn(II).The extraction of Ni(II) with STTA was accelerated by the addition of phen due to the formation of labile species, Ni(phen)_<2+> and Ni(phen)_2^<2+>. In contrast, Ni(phen)_3^<2+> was found to be inert toward STTA anion. If Co(phen)_3^<2+> is labile, it is expected that Co(II) can be extracted preferentially while Ni(phen)_3^<2+> remains in the aqueous phase. On the bases of the above principle, the quantitative separation of Co(IIr from Ni(II) was performed by using dithizone-phen system,in which phen was added preliminarily in the aqueous phase to ensure the quantitative formation of Ni(phen)_3^<2+>.Finally, a synergistic extraction system was also applied to a method for the preconcentration of trace metal ions. As a result, a trace amount of Cd(II) in natural river water samples could be determined by employing dithizone and tributylphosphine oxide extraction system and atomic absorption spectrometry.