Comparison of different extraction methods for the determination of fatty acid methyl esters in mussels’ samples

The profiling of fatty acids (FAs) involves an analytical approach that offers detailed information regarding the qualitative and quantitative distribution of FAs in food products. This technique, when combined with high-capacity analytical methods, aids in addressing numerous questions related to the nutritional quality and authenticity of food. In natural samples, FAs are primarily found in esterified forms as triglycerides, necessitating their conversion into fatty acid methyl esters (FAMEs) prior to gas chromatography analysis for precise profiling. Prior to any derivatization reaction, lipid extraction from complex matrices, apart from pure fats and oils, is necessary. In this work, three methods for the extraction and derivatization of FAMEs are used. In particular, the fatty acids profile obtained with the microwaves-assisted extraction and derivatization (MAED) was compared with the one obtained from the conventional FAMEs preparation method. The microwave-assisted method proved to be fast, simple, and effective for analysing complex samples like mussels. The FAMEs were subsequently analysed using reversed fill/flush differential-flow modulation comprehensive two-dimensional gas chromatography (GCxGC) coupled with flame ionization detection (FID) to identify and quantify individual fatty acids. GCxGC analysis offers superior separation power compared to one-dimensional GC and generates structured chromatograms based on the chemical patterns, enhancing the reliability and accuracy of identification. Additionally, the environmental impact of the method was evaluated based on the recently published PrepAGREE criteria, demonstrating superior performances compared to official methods in terms of greenness.