Investigation of iron oxide nanoparticles by capillary zone electrophoresis.

The electrophoretic behavior of gamma-Fe(2)O(3) nanoparticles was studied in aqueous solutions of Na(2)SO(4)-NaOH (pH 10.8) and of Na(2)SO(4)-Na(3)cit (pH 7.1) as running electrolytes. Two electrophoretic zones (smooth and with spikes) due to colloidal and suspended particles of approximately the same size range were formed during the runs. The suspension stability and size distribution were shown to depend on the composition of electrolyte used for dispersing the solids. The effects of electric field strength, injection time, injection pressure as well as sodium citrate concentration were studied and particle electrophoretic mobilities were calculated. Electron micrographs of particles studied were obtained. Preparation of reference samples based on the colloidal gamma-Fe(2)O(3) has been discussed.