Date of Award
Master of Science
Dr. Subra Muralidharan
Dr. Donald R. Schreiber
Dr. Brian P. Buffin
Masters Thesis-Open Access
Transition-metal (Zn(II), Co(II), Ni(II) and Cu(II)) ion separation was studied using 8-hydroxyquinoline-5-sulfonic acid and 2-methyl-8-hydroxyquinoline ligands with surfactants (cationic and anionic) by capillary electrophoresis under a variety of conditions (like pH, ionic strength, voltage and ion, ligand and surfactant amounts) and has debuted a clear separation mechanism. With cationic surfactants, ligands compete with capillary surface silanols for the metal ions; with anionic surfactants, ligands, silanols and micelles compete.
An empirical parameter, Ke, (electrophoretic-mobilities based) rationalizing the separation was proposed, experimentally analyzed and supported; it provides a silanol group per cm2 value of the capillary surface, an equilibrium constant for the exchange of metal ions between the micelles and the complexes, and a quantitative and fundamental understanding of the electropherograms and separation mechanisms.
Capillary pretreatment with low cationic amour.ts makes constant, reproducible concentrations of surface silanol groups that, with ligands, exchange ions with mobile phase complexes (resulting in different mobilities for different ion complexes) and that, with anionic surfactants above critical micelle concentration, exchange ions with micelles (resulting in different migrations for different ion complexes).
Hofman, "Capillary Electrophoretic Separations of Metal Ions" (2003). Master's Theses. 4882.