Gel filtration profiles obtained from a variety of naturally colored waters indicate that color producing molecules are mostly in the apparent molecular weight range of 700-10,000 relative to dextrans.One fraction seems to have a molecular weight in excess of 50,000. The apparent size of the color molecules was found to be pH dependent, increasing as pH increases.Size increases are attributed to increased functional group ionization and a decrease in the adsorbability on Sephadex. The degree of association of color molecules with iron was also found to bc pH dependent, being greater at both high and low pH than in the range of 7-8.
The primary objectives of this study were to investigate the chemical structures of color molecules, the similarity of colored waters from different sources, and the environmental factors involved in the production of color. Oxidation with alkaline‐CuO was found to be an effective method of degrading the complex color molecule to recognizable chemical structures. Evaluation of the effect of the oxidation technique on model compounds, coupled with the knowledge of seven color degradation products, resulted in the proposal of a hypothetic structural formula for color‐producing molecules in water. Further experiments revealed a close similarity between the degradation products of color solids and the water‐soluble organic components of wood and soil.
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