Fujii Toshiyuki, Moynier Frédéric, Telouk Philippe, Albarède Francis
Research Reactor Institute, Kyoto University, 2-1010 Asashiro Nishi, Kumatori, Sennan Osaka 590-0494, Japan.
J Phys Chem A. 2006 Sep 28;110(38):11108-12. doi: 10.1021/jp063179u.
This work reports on the chemical isotope fractionation of Fe(III) by a solvent extraction method with a crown ether of dicyclohexano-18-crown-6. The (56)Fe/(54)Fe and (57)Fe/(54)Fe ratios were analyzed by multiple-collector inductively coupled plasma mass spectrometry. We determined the dependence of the isotope enrichment factors (epsilon) on the strength of HCl. The relative deviation of the (56)Fe/(54)Fe ratios relative to the unprocessed material (10(4) epsilon(56)) increases from -15.3 to -6.3 with [HCl] increasing from 1.6 to 3.5 mol/L. Likewise, 10(4) epsilon(57) increases from -22.8 to -9.6 under the same conditions. The correlation between epsilon(56) and epsilon(57) is mass dependent within the errors. The observed fractionation was broken down into the effects of competing extraction reactions and of a reaction between Fe(III) species (FeCl(2)(+) and FeCl(3)) in the aqueous phase. We found that the isotope fractionation between the Fe(III) species is mass dependent, which we confirmed by calculating the reduced partition function ratios.
本研究报道了采用二环己基-18-冠-6冠醚通过溶剂萃取法对Fe(III)进行化学同位素分馏的情况。通过多接收电感耦合等离子体质谱法分析了(56)Fe/(54)Fe和(57)Fe/(54)Fe比值。我们确定了同位素富集因子(ε)对HCl浓度的依赖性。随着[HCl]从1.6 mol/L增加到3.5 mol/L，(56)Fe/(54)Fe比值相对于未处理材料的相对偏差(10(4)ε(56))从-15.3增加到-6.3。同样，在相同条件下，10(4)ε(57)从-22.8增加到-9.6。在误差范围内，ε(56)和ε(57)之间的相关性与质量有关。观察到的分馏被分解为竞争性萃取反应的影响以及水相中Fe(III)物种(FeCl(2)(+)和FeCl(3))之间反应的影响。我们发现Fe(III)物种之间的同位素分馏与质量有关，这通过计算约化分配函数比得到了证实。
