Determination of Free Fatty Acids in Foodstuff by Solid Phase Extraction and Gas Chromatography-Flame Ionization Detection Using H₂SO₄-MeOH Derivatization

Free fatty acids (FFAs) serve as crucial analytical markers in oils, fats, and food, reflecting food safety through their content variations. However, the analysis of FFAs in food samples is constrained by potential interferences from other acidic components in the sample matrix during sample processing, resulting in distorted analytical outcomes and introducing positive bias. The established method was also validated in terms of linearity, limits of detection (LOD) and quantification (LOQ), and matrix effect. It was proved to be linear (R² > 0.99), with lower LODs of 0.108–0.564 μg/mL, and lower LOQs of 0.258–1.541 μg/mL for all FFAs. Overall, the simple, rapid, and cost-effective method developed in this study provides a potential application for the extraction and enrichment of FFAs in complex sample matrices, including edible oils, fatty foods, and high-content biological samples.