Data Set for Analytical Validation of a GC–MS Method Employing An In Situ Acid-Catalyzed Transmethylation for Fatty Acid Quantification in Aquaculture Biological Matrices

This study presents the analytical validation of a gas chromatography–mass spectrometry (GC–MS) method employing an in situ acid-catalyzed transmethylation approach for the quantitative determination of fatty acids in aquaculture-relevant biological matrices. The method integrates direct transmethylation with selected-ion monitoring (SIM) to enable accurate and reproducible fatty acid methyl ester (FAME) analysis from feeds and fish tissues while minimizing sample handling and lipid extraction steps. Method performance was evaluated in terms of linearity, sensitivity, precision, accuracy, and recovery using authenticated standards and an internal standard, demonstrating robustness across complex lipid matrices. The validated protocol provides a reliable and efficient analytical framework for fatty acid profiling in aquaculture nutrition and feed biotechnology studies, supporting high-throughput lipid analysis with strong analytical confidence.