Elena Hofman

Date of Award


Degree Name

Master of Science



First Advisor

Dr. Subra Muralidharan

Second Advisor

Dr. Donald R. Schreiber

Third Advisor

Dr. Brian P. Buffin

Access Setting

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).

Included in

Chemistry Commons