In 1964, a method was described for the determination of free fatty acids (FFAs) in vegetable oil. This paper describes an expansion of that work, improving the sensitivity and reproducibility of the method, as well as examination of solubilities of the copper soaps as a function of chain length and unsaturation. Involvement of the micellar structure was reviewed. Finally, a procedure is described that permits very rapid determination of FFA at the 2.0-14.0/~mol (0.5-4.0 mg oleic acid) level, and the results with several oils are given. Particular attention was given to evaluation of solvent systems which would extract the copper complexes.

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A method is described for quantitatively determining lipid phosphorus with a linear range from 0.7–10.0 μg. The method is simple and rapid, requiring one stable reagent and a single extraction with 1‐butyl acetate after the phosphorus is converted to inorganic phosphate by means of a perchlorate digestion. The stable complex is read at 310 nm.

1. Caddisflies (Trichoptera) that shred leaf detritus preferentially ingested lipid-coated detritus during the last larval instar. This is the interval when these insects accumulate the triglyceride reserves necessary for metamorphosis and reproduction. Early instar larvae, which do not accumulate lipids, showed no preference for any lipids. This behaviour indicates food selection based on changing nutritional needs.2. Pure unsaturated 18-and 20-carbon fatty acids, either as free acids or triglycerides, were most strongly preferred. Crude lipid and the neutral lipid fraction from aquatic hyphomycete fungi, an important component of aquatic leaf detritus, were also preferred.3. Tipula abdominalis (Diptera: Tipulidae) did not prefer any lipids during the last instar.

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