Analysis of Yellow Organic Matter From Fresh Water

Abstract

This study examined various techniques of soil analysis and organic chemistry to gain information on yellow organic compounds, particularly fulvic acid, in water. The yellow color from organic matter in a pond surrounded by muckpeat soil was reduced from 55 units to 38 units by filtration through a 10 mµ filter. In an unfiltered sample, a sediment formed on the bottom of a flask over a 12 month period, reducing the color to 45 units. A large portion of the yellow organic matter, however, was soluble or colloidal material that appeared to be resistant to both biologic and chemical degradation. A water sample was filtered through a 100 mµ filter, and the water was evaporated leaving a material of which 27.18 per cent was lost on ignition at 600ºC. This material contained four free amino acids, and acid hydrolysis released ten more amino acids. The material lost by ignition contained 0.644 per cent amino acids and 6.48 per cent carbohydrates. Various treatments of the original material produced many fractions that were analyzed for carbon and nitrogen. Infrared absorption spectra of these fractions were also recorded. Over 80 per cent of the carbon was found to be in the fulvic acid fraction, and infrared absorption spectra indicated this material to be aromatic carboxylic acids with aliphatic side groups containing alcoholic or phenolic hydroxyl groups.