Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA.
J Chromatogr A. 2012 Jul 6;1245:83-9. doi: 10.1016/j.chroma.2012.05.036. Epub 2012 May 17.
The selectivity and separation of transition metal ions on two columns packed with cyclen-based macrocycles adsorbed onto 55% cross-linked styrene-divinylbenzene resin are presented. The N-cyclen and cyclen-resorcinarene stationary phases were made by adsorbing hydrophobically substituted N-cyclen or a cyclen-resorcinarene derivative (cyclenbowl) on the resin, respectively. The stability constants of cyclen with transition metal ions demonstrate that cyclen has selectivity for Cu²⁺ over other transition metal ions. Mn²⁺, Co²⁺, Ni²⁺, Cd²⁺, and Zn²⁺ ions were separated from Cu²⁺ using HNO₃ eluent with the cyclenbowl column. The preconcentration of Cu²⁺ in parts per billion level from a high concentration matrix of Mn²⁺, Co²⁺, Ni²⁺, Cd²⁺, and Zn²⁺ ions was achieved in the cyclenbowl column using a nitric acid eluent gradient. Recovery of Cu²⁺ at >98% was obtained based on direct interaction of metal ion and cyclen. Although Mn²⁺, Co²⁺, Ni²⁺, Cd²⁺, and Zn²⁺ were not separated by HNO₃ eluent, addition of oxalic acid yielded a very good separation. A retention mechanism is proposed for the latter system in which the protonated cyclen units attract negatively charged HC₂O₄⁻ ions that cooperate with cyclen sites in retaining transition metal ions.
本文介绍了两种基于环戊二烯基大环吸附在 55%交联苯乙烯-二乙烯基苯树脂上的填充柱对过渡金属离子的选择性和分离。N-环戊二烯和环戊二烯-间苯二酚树脂固定相是通过将疏水性取代的 N-环戊二烯或环戊二烯-间苯二酚衍生物（环戊二烯碗）分别吸附在树脂上来制备的。环戊二烯与过渡金属离子的稳定常数表明，环戊二烯对 Cu²⁺具有选择性，而对其他过渡金属离子则没有选择性。使用 HNO₃洗脱液，Mn²⁺、Co²⁺、Ni²⁺、Cd²⁺和 Zn²⁺离子可以从 Cu²⁺中分离出来，使用环戊二烯碗柱。使用硝酸洗脱液梯度，在 Mn²⁺、Co²⁺、Ni²⁺、Cd²⁺和 Zn²⁺离子的高浓度基质中，Cu²⁺可以在环戊二烯碗柱中实现十亿分之几水平的预浓缩。基于金属离子与环戊二烯的直接相互作用，Cu²⁺的回收率达到了>98%。尽管 Mn²⁺、Co²⁺、Ni²⁺、Cd²⁺和 Zn²⁺不能用 HNO₃洗脱液分离，但添加草酸可以得到很好的分离。提出了后一种体系的保留机制，其中质子化的环戊二烯单元吸引带负电荷的 HC₂O₄⁻离子，这些离子与环戊二烯位合作，保留过渡金属离子。
