IRON(III) ION-MODIFIED CHROMATOGRAPHIC SILICA PREPARATIONS AND CHARACTERIZATION

Stable, reproducible, iron(III) ion-modified silica stationary phases were prepared in aqueous media by a batch process. The catalytic activity of this modified stationary phase for oxidation of hydroquinone to benzoquinone was considerably greater than that of earlier iron(III) ion-modified silicas from non-aqueous media. Capacity factors of selected solutes were used to compare the retention properties of the aqueous iron(III) ion-modified silica with those of the unmodified silica. The capacity factors for solutes containing hydroxyl groups tended to increase with the iron(III) ion-modified silica relative to those for the unmodified silica column, whereas the capacity factors for carbonyl-containing compounds (esters. ketones and aldehydes) became smaller or were unaffected.