Aminophosphonate-Functionalized Silica: A Versatile Chromatographic Stationary Phase for High-Performance Chelation Ion Chromatography

✍ Scribed by P.N. Nesterenko; M.J. Shaw; S.J. Hill; P. Jones

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 87 KB
• Volume: 62
• Category: Article
• ISSN: 0026-265X
• DOI: 10.1006/mchj.1999.1717

✦ Synopsis

The chromatographic behavior of alkaline earth metals, Cu(II), Mn(II), Co(II), Zn(II), Ni(II), Pb(II), and Cd(II) on a chelating aminomethylphosphonic acid-functionalized silica column was studied in eluants with high ionic strength to suppress ion exchange. Unusual variations were found in plots of capacity factor against pH demonstrating changes in retention order, suggesting a change in the coordination of metal ions from O,O to N,O,O chelation. Increased affinity of the chelating ion exchanger to heavy metals and in particular Mn(II) was observed at low pH. Examples are shown of high-efficiency separations of groups of metal species with varying retention orders at different pH values, including a separation of eight metal species in under 16 min. These characteristics make aminophosphonate chelating substrates a useful and more versatile phase for high-performance chelation ion chromatography than iminodiacetate phases.