Anion separations on columns based on transition metal-macrocycle complex exchange sites

• Published in: Journal of Chromatography A Vol. 671; no. 1; pp. 55 - 62
• Main Authors: Lamb, John D., Smith, Robert G., Anderson, Randal C., Mortensen, Max K.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 10.06.1994; Elsevier
• Subjects: Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Exact sciences and technology; Other chromatographic methods; Ion chromatography; Protonation constant; Transition metal Ions; Nitrogen crown compound; Column packing; Preparation; Cryptand; Eluent; Ligand exchange chromatography
• ISSN: 0021-9673
• DOI: 10.1016/0021-9673(94)80221-1

Macrocycle-based ion chromatographic columns can provide fast and effective separations of inorganic anions. Chromatographic columns based on nitrogen-containing macrocycles such as cryptand decyl-2.2.2 (D222) and didecyl-diaza-18-crown-6 (DD22) have high affinities for transition metal cations. This work compares the chromatographic separation of anions using transition metal cation eluents in columns based on the macrocyclic ligands DD22 and D222 adsorbed on two different polystyrene resins, MPIC and AS10 (Dionex). When a transition metal ion, e.g. Cu 2+, Ni 2+, or Co 2+, was present in the mobile phase flowing through an MPIC column loaded with didecyl-diaza-18-crown-6, anion separations of differing selectivities were obtained. Separations of anions were achieved with these columns even when only a cation that has low affinity for the macrocycles, such as Li +, was included in the mobile phase. This is due to protonation of the nitrogen atoms in the macrocycles. Columns based on the AS10 type resin produced much higher efficiency and shorter retention times than did columns based on the MPIC resin.