The effect of dissolved oxygen concentration on the ionization and valence of four food grade iron compounds was investigated. Nitrogen and oxygen gases were bubbled in varying ratios into potassium biphthalate buffers, pH 4.2, until the desired level of oxygen (<1, 6 or 12 μg/ml) was reached. The iron compounds were added, then analyzed for total ionic iron and ferrous ion concentrations after 2, 7, 14, 21 and 28 days. This model system showed that the concentration of dissolved oxygen had no significant effect on the percentage of added iron that became ionized or the percentage of iron present in the ferrous state.
1The Procter & Gamble Company.
2University of Massachusetts.