SAMPLE PREPARATION STRATEGIES FOR LIPIDOMICSINVESTIGATION IN FOOD ANALYSIS. CASE OF STUDY:EXTRACTION AND ANALYTICAL DETERMINATION OF THE LIPIDFRACTION IN HIGH-QUALITY FOOD (BRONTE SICILIANPISTACHIOS)

This study evaluates the performance of microwave‑assisted extraction (MAE) for lipid analysis in high-lipidic food matrices (raw Sicilian pistachios), using methyl‑tert‑butyl ether (MTBE) either as a single organic solvent or in combination with methanol and water. The MAE procedures were compared against conventional extraction methods, including Soxhlet extraction (using n‑hexane, MTBE, and diethyl ether) and the Matyash method (methyl‑tert‑butyl ether/methanol/water, 10/3/2.5, v/v/v). One-way ANOVA and post-hoc Tukey tests were used to identify statistical differences in yields and FA methyl esters (MEs) composition. FAMEs were analyzed qualitatively using comprehensive two‑dimensional gas chromatography coupled with time‑of‑flight mass spectrometry (GC×GC‑TOFMS) and quantified using gas chromatography with flame ionization detection (GC‑FID). All extraction approaches provided comparable FA profiles, while a greenness evaluation of the seven methods showed that MAE using MTBE achieved the highest Analytical GREEnness Metric for sample preparation (AGREEprep) score. The lipid extract obtained by MAE‑MTBE was further separated by solid‑phase extraction (SPE) into four lipid classes based on their polarity. One set of fractions was analyzed for intact lipids by a reversed-phase ultra‑high‑performance liquid chromatography coupled with a quadrupole mass spectrometer equipped with an atmospheric pressure chemical ionization interface operating in both positive and negative polarity (UHPLC‑(+/–)APCI‑qMS). A second set was derivatized in FAMEs and analyzed by GC‑FID to determine the FA composition within each lipid class.