PH-METRIC DETERMINATION OF THE ACID VALUE OF VEGETABLE-OILS WITHOUT TITRATION

The acid value (AV) of vegetable oils is determined without titration by using a new reagent consisting of triethanolamine in a solution of water and isopropyl alcohol. When the oil sample is mixed with the rea gent in the pH-metric cell, free fatty acids from the sample are extra cted into the reagent (3-4 min). The initial pH, called conditional pH '(1), is measured, a standard acid (HCl) is added, and the final pH, p H'(2), is measured. AV is calculated from the difference between pH'(1 ) and pH'(2). The method is applicable for quality control of vegetabl e oils during their production, trade, and use.