Voltammetric Determination of Acid Values of Fats and Oils

Abstract

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 × 10−6 to 6 × 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 acidbase indicators in organic solvents.

Interference of polar lipids with the alkalimetric determination of free fatty acid in fish lipids

“…Variations exist in the acidity determined by different alkali- metric methods endorsed by various international organizations (23). Investigations on the improvement of method sensitivity and accuracy have been based on changing the indicator (24) or by measuring the reduction prepeak current of FFA (25). The latter group also observed higher acid values with a color (phenolphthalein) indicator method than with voltammetry or potentiometry, confirming our findings.…”

Analytical approaches for the assessment of free fatty acids in oils and fats

“…29 It was reported that the reduced form of quinone (dissolved in ethanol) gave a very strong voltammetric signal in the presence of acids. For analysis of FFA in edible oils, the behavior of quinone has been utilized by various authors [30][31][32][33][34] to develop HPLC and FIA methods. The FIA system coupled with voltammetric detection gave results with a high sensitivity and better reproducibility, and the method had a low solvent consumption and an excellent throughput of 60 samples per h. Unfortunately this technique did not get much attention.…”

Fast Rate Production of Biodiesel from Neem Seed Oil Using a Catalyst Made from Banana Peel Ash Loaded with Metal Oxide (Li‐CaO/Fe2 (SO4)3)

“…e AV was calculated using the following equation [36]: acid value � titre volume × grams of NaOH in 0.1 M of NaOH solution sample weight in grams .…”