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Rapid colorimetric determination of free fatty acids


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 µmol (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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Technical Paper No. 4036, Oregon Agricultural Experiment Station.

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Lowry, R.R., Tinsley, I.J. Rapid colorimetric determination of free fatty acids. J Am Oil Chem Soc 53, 470–472 (1976).

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  • Free Fatty Acid
  • Oleic Acid
  • Isobutyl Alcohol
  • Cupric Acetate
  • Saturated Free Fatty Acid