Sample preparation and enrichment for the analysis of perfluorinated alkyl substances (PFAS) in environmental samples such as water and soil is a critical step to obtain accurate and reliable results. Various methods and materials are used to avoid contamination and to enrich and purify the desired PFAS compounds. One example is solid phase extraction (SPE), a widely used method to enrich and purify PFAS from various matrices. SPE cartridges with materials such as WAX (polymer-based weak anion exchanger) or GCB/WAX are used to selectively bind PFAS and remove impurities.