Comparative evaluation of intra-tube flux extraction and solid-phase microextraction for the determination of polycyclic aromatic hydrocarbons in marginal lagoons by GC×GC/MS

Polycyclic aromatic hydrocarbons (PAHs) are priority environmental contaminants frequently detected at trace levels in aquatic systems, necessitating sensitive and reliable analytical methodologies for their determination. In this study, a comparative analytical evaluation of intra-tube flow extraction (IT-FEx) and solid-phase microextraction (SPME) was conducted for the determination of PAHs in water samples. Both extraction techniques were optimized and coupled to comprehensive two-dimensional gas chromatography, and their analytical performance was assessed for linearity, sensitivity, precision, accuracy, and applicability to real samples. The methods showed good linearity for all target compounds. For the IT-FEx-based method, limits of detection ranged from 0.005 to 8.107 μg L −1 , while limits of quantification ranged from 0.024 to 9.197 μg L −1 , depending on the compound. The methods showed good linearity for all target compounds, with coefficients of determination (R 2 ) ranging from 0.90 to 0.99. Precision, expressed as intra- and inter-day relative standard deviation, ranged from 6.6% to 14.8%, and recoveries from spiked water samples were within the acceptable range of 80–120%, demonstrating satisfactory accuracy. Application of both methods to real water samples revealed clear differences in extraction performance. IT-FEx enabled the detection of a broader range of PAHs and yielded higher ΣPAH concentrations, allowing simultaneous extraction of compounds of different molecular weights. In contrast, SPME exhibited more selective extraction, with several PAHs detected at concentrations near the quantification limits. Overall, the results show that IT-FEx provides improved analytical coverage and comparable or higher sensitivity for most analytes, which can be attributed to its flow-assisted extraction mechanism that enhances mass transfer and minimizes diffusional limitations. These characteristics make IT-FEx a robust, efficient, and environmentally sustainable alternative for the determination of PAHs in water matrices.