Determination of free fatty acids (FFA) in edible oils with thermometric titration
AB-315
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In titration, the titrant reacts with the analyte either exothermically (gives off heat) or endothermically (absorbs heat). The Thermoprobe measures the temperature change during titration. When all of the analyte has reacted with the titrant, the temperature of the solution will change, and the endpoint of the titration is indicated by an inflection in the temperature curve. Catalytically enhanced titrations using paraformaldehyde as catalyst are based on the endothermic hydrolysis of the paraformaldehyde in the presence of excess hydroxide ions. Edible oils are dissolved in a mixture of toluene and 2-propanol (1:1) and titrated with standardized TBAH (0.01 mol/L) in 2-propanol to a catalytically enhanced endpoint.
The free fatty acids (FFA) in edible oils can be determined by thermometric titration. Since the exothermic reaction between the FFA and alcoholic TBAOH is too weak, a catalytically enhanced thermometric titration is used. The catalyst acts as an indicator for the endpoint. For the FFA titration, paraformaldehyde is used as a catalyst due to the endothermic hydrolysis of the paraformaldehyde in the presence of excess hydroxide ions. This results in a strongly exothermic endpoint, which can be detected reliably.