Quantitative profiling of fatty acids in tropical oysters (Crassostrea spp.) using dispersive liquid-liquid...

A method integrating dispersive liquid-liquid microextraction (DLLME) with comprehensive two-dimensional gas chromatography-flame ionisation detection (GC×GC-FID) was developed for the simultaneous extraction, separation, and quantification of major fatty acids (FAs) in Malaysian mangrove oysters. DLLME parameters, including the type and volume of extractant and dispersant, pH, and ionic strength were optimised to improve extraction performance. GC×GC separation was effected using high-polarity first-dimension and polar second-dimension column phases, with a 4 s modulation period to achieve interference-free FAs separation. The DLLME-GC×GC-FID method demonstrated good linearity (10.0-250 mg/L; r²>0.99), with detection limits of 2.801-8.134 mg/L, intra- and inter-day precision ≤9.82%, with recoveries ranging from 86.64 to 113.6%. The validated method was successfully applied to profile saturated, monounsaturated, and polyunsaturated FAs in fresh Crassostrea iredalei, Crassostrea belcheri, and commercially imported oysters. This method offers potential as a high-resolution analytical tool for FAs profiling and fingerprinting in complex oyster matrices.