The Puzzle of Lost PAHs: A Step-by-Step Investigation of Pre-, During-, and Post-Solid-Phase Extraction from Water Samples

Abstract

The development of an accurate method to extract polycyclic aromatic hydrocarbon (PAH) from water samples is crucial for assessing environmental contamination and protecting public health. Solid-phase extraction (SPE) remains the selected technique for extracting trace contaminants from water due to its high precision, selectivity, and reproducibility. However, extracting the 18 PAH compounds proved challenging, as not all target compounds were fully recovered. Various SPE sorbents and elution solvents were tested to minimize analyte losses, but no substantial improvements were initially observed. To address this issue, ‘keeper’ solvents were added after the elution step, resulting in moderate improvements in recovery; however, optimal results were not achieved. Further optimization efforts focused on the evaporation step, which was identified as a critical step due to the volatilization of low molecular weight PAHs during solvent drying. Refinements to this step showed improved analytical performance, ensuring the more complete and reliable recovery of all studied PAHs. The optimized method was successfully applied to diverse types of water samples, showing its applicability and effectiveness in detecting PAH contamination from multiple sources in aquatic environments. This methodology provides a valuable tool for environmental monitoring and reinforces the importance of controlling PAH pollution to protect ecosystems and human health.