Sequential ultrasonic solvent-assisted gas-liquid microextraction for the quantification of polycyclic aromatic...

In this study, an integrated solid-phase extraction (SPE) and gas-liquid microextraction (GLME) technique was developed for the purification of lipid-soluble substances in complex matrices, which was applied to the quantitative determination of 16 polycyclic aromatic hydrocarbons (PAHs) in high-fat seafood. During sample pretreatment, ultrasonic-assisted extraction followed by sequential SPE-GLME purification effectively removed over 97 % of the fat-soluble compounds, particularly interfering components such as fatty acids, organic esters and alkanes, before being subjected to GC-MS analysis. Analytical performance was systematically validated, showcasing excellent accuracy (spiked recoveries of 81.7-102.9 %), outstanding precision (relative standard deviations, RSDs (n = 3) of 0.6-24.7 %), high sensitivity (method detection limits, MDLs in the range of 0.12-1.70 μg kg^‒1), and remarkable cleanup capacity (over 97 % of target analytes across six seafood samples exhibited matrix effects within ±20 %). This analytical protocol was further applied to analyze various high-fat seafood species, which revealed individual PAH concentrations ranging from 1.45 to 65.61 μg kg^‒1 dw. Notably, seven of the 16 priority PAHs were quantified with 100 % detection frequency in all samples. Moreover, a significant negative correlation was observed between PAH concentrations and their physicochemical properties, such as molecular weight, boiling point, and log P (Spearman ρ = -0.875 to -0.902, p < 0.01). This suggests that lighter, less hydrophobic PAHs, with lower log P values, tend to be present at higher concentrations in seafood samples, possibly due to their higher environmental mobility and bioavailability. Overall, the developed ultrasonication-SPE-GLME-GC-MS analytical method stood out with its exceptional elimination of co-extracted interferences for accurate PAH determination in lipid-rich seafood matrices, thus offering a robust analytical approach for monitoring organic contamination and safeguarding food safety.