VOLTAMMETRIC DETERMINATION OF ACID VALUES OF FATS AND OILS

A new method for determining acid values of fats and oils was developed based on measurement of reduction prepeak current of 2-methyl-1,4-naphthoquinone (VK3) from 8 x10(-6) to 6 x 10(-3) M, due to free fatty acid (e.g., linoleic acid). Acid value of 11 samples was determined. The relative standard deviation of acid value for 5 replicates of each sample was less than 2.5%. The method is superior to conventional titration methods in sensitivity and overcomes inaccuracy due to vagueness in color change of acid-base indicators in organic solvents.