The method describes how to determine the presence of oil in water.
Oils and fats may be present in water and wastewater, predominantly in the form of emulsions, suspensions or in a colloidal state, but they may also be, for all practical purposes, dissolved in the water. This applies to fats derived from animal and plant products as well as to mineral oils and fats. Oils and fats do not entirely amass on the surface of the water sample but may be dispersed throughout it; therefore, special treatment is required for a quantitative determination.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
Oils and fats dispersed in water are precipitated using aluminum sulfate. After dissolving the precipitate with hydrochloric acid in organic solvents, they can be separated from the mineral salts.