Gas-liquid microextraction coupled with magnetic-assisted dispersive solid-phase extraction clean-up for multi-residue pesticide analysis in fatty foods of animal origin

An effective sequential clean-up method by coupling gas-liquid microextraction (GLME) and magnetic-assisted dispersive solid phase extraction (d-SPE) termed as GLME-MA-d-SPE has been developed for multi-residue pesticide analysis in different fatty foods of animal origin. GLME is applied as a primary clean-up step to remove low-volatile interferences, followed by a secondary clean-up technique through adsorptive removal using d-SPE to eliminate other co-extracts like organic acids in fatty biological samples. As much as 99.3% of lipid substances were effectively eliminated by this powerful clean-up method, and the chromatographic analysis by GC-MS showed at least two orders of magnitude reduction for peaks of interference. Analytical results verified the accuracy and precision of this method with recoveries of 50 pesticides ranged from 60.5% to 119.7%, and RSDs of less than 20%. Permethrin was present in salmon, pork and egg samples, but the concentrations were within the maximum residue levels (MRLs) permitted by both national and international regulations. The GLME-MA-d-SPE technique minimizes matrix effects, and it exhibits significant potential as an analytical technique of food safety control systems for broad-spectrum screening trace-level environmental pollutants in complex biological matrices.