Gel Chromatographic Behavior of Aqueous Ferric Nitrate

Abstract

Ferric nitrate solutions with different degrees of hydrolysis were investigated on polydextran gels having various exclusion limits. Typically chromatograms exhibited two well-resolved peaks, one at the void volume and the other at the total liquid volume of the gel. The respective peaks corresponded to higher and lower molecular weight fractions of the iron in the injected sample. Similar behavior was observed in “negative-peak” investigations where the positions of sample and eluent were reversed. Frontal analysis of the iron solution showed two breakthroughs corresponding to excluded iron moving in the void volume and admitted iron moving near the total liquid volume of the gel. The molecular size distribution of the ferric nitrate samples was studied as a function of OH-Fe ratio by noting changes in the percentage of iron in the respective fractions for gels having known exclusion limits.