From waste to resources: sample preparation strategies coupled with GC×GC-TOFMS for characterizing wind turbine blade recycling products

The recycling of End-of-life wind turbine blades represents a growing challenge in the context of sustainable materials management. In this work, two recycling processes—solvolysis and pyrolysis—were investigated, each supported by a dedicated sample preparation strategy prior to the detailed characterization of the resulting products. For solvolysis products, microwave-assisted extraction (MAE) was carried out using a hexane–methanol mixture (10:3 ratio), followed by water addition (2.5 ratio) and centrifugation to separate the phases. Pyrolysis products, in parallel, were subjected to solid-phase extraction (SPE), enabling the isolation of different chemical classes. The resulting MAE extracts and SPE fractions were subsequently analyzed using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS). Compound identification was based on mass spectral electron ionization (EI) database matching at 70 eV (≥800/1000) and the Linear Retention Index (LRI) (±20 range). The location of the investigated molecules on the 2D-GC plane was also considered. Overall, around 120 compounds belonging to different chemical classes such as hydrocarbons, aromatics, and heteroatom-containing molecules were identified in the solvolysis products. For the SPE fractions of pyrolysis-derived products, the use of a normal-phase sorbent with eluting solvents of increasing polarity allowed for the separation of hydrocarbon-rich fraction from one enriched in oxygen- and nitrogen-containing compounds.