Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA.
Analyst. 2013 Mar 7;138(5):1467-74. doi: 10.1039/c2an36562f.
A resorcinarene-based macrocyclic ligand functionalized with alanine and undecyl groups (AUA) was synthesized and applied to ion chromatographic separations. The selectivity and separation of transition metal ions on a column packed with AUA adsorbed onto 55% cross-linked styrene-divinylbenzene resin are presented. The upper and lower rims of the resorcinarene were modified with amino acids and -C(11)H(23) alkyl chains, respectively. The four carboxylic acid groups on the upper rim act as cation-exchangers while the four -C(11)H(23) alkyl chains serve to anchor the ligand to the resin surface by the hydrophobic effect. A systematic study of the effect of different eluent components including non-metal-chelating (HNO(3)) and chelating acids (oxalic acid, succinic acid, dipicolinic acid, and citric acid) on the retention of transition metal ions was investigated. Six metal ions (Mn(2+), Co(2+), Ni(2+), Cd(2+), Cu(2+), and Zn(2+)) were separated on the AUA column within a reasonable time with a single eluent gradient using oxalic acid. The separation is compared to that obtained using a commercial column containing carboxylic acid functional groups. The AUA column containing four preorganized carboxylic acid groups showed selectivity for Cu(2+) when no chelating eluent was present, a selectivity which was not observed with the comparison column.
一种基于雷琐酚的大环配体，同时带有丙氨酸和十一烷基基团（AUA）被合成出来并应用于离子色谱分离中。本文介绍了在填充有通过 55%交联苯乙烯-二乙烯基苯树脂吸附的 AUA 的柱子上，过渡金属离子的选择性和分离情况。雷琐酚的上边缘和下边缘分别被氨基酸和-C(11)H(23)烷基链修饰。上边缘的四个羧酸基团作为阳离子交换剂，而四个-C(11)H(23)烷基链通过疏水作用将配体锚定在树脂表面上。本文系统地研究了不同洗脱剂成分（包括非金属螯合剂（HNO(3)）和螯合剂（草酸、琥珀酸、二吡啶甲酸和柠檬酸））对过渡金属离子保留的影响。在使用草酸的单一洗脱梯度下，六种金属离子（Mn(2+)、Co(2+)、Ni(2+)、Cd(2+)、Cu(2+)和 Zn(2+)）在 AUA 柱上在合理的时间内得到了分离。与含有羧酸官能团的商业柱相比，AUA 柱对没有螯合洗脱剂存在时的 Cu(2+)表现出选择性，而比较柱则没有观察到这种选择性。
