Sample preparation approaches coupled with GC×GC-MS for the characterization of new energy materials wastes

The goal of this project was to develop analytical solutions to understand better the recycling of chemicals and valuable materials from wind turbine blades, addressing the need for sustainable end-of-life solutions for renewable energy infrastructure. Wind turbine blades underwent solvolysis treatments for 8 and 13 hours. The resulting solvolysis mixtures, referred to as solvolysis soups, with highly basic pH levels, were neutralized. Afterwards, while the solid phases were directly processed after neutralization, the liquid phases needed an additional filtration step to remove solid residues from them. Microwave-assisted extraction (MAE) was performed on the products of these procedures using a hexane-methanol solvent mixture (10:3 ratio), followed by water addition (2.5 ratio) and centrifugation. Subsequently, the organic phase was collected, concentrated, and analyzed using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS). The system was equipped with a non-polar column in the first dimension and a medium-polar column in the second dimension, connected with a cryogenic modulator. Due to this MAE-GC×GC-MS technique, it was possible to identify approximately 60 molecules from various chemical classes, including aromatic compounds, and nitrogen- and oxygen-containing compounds. Identification was achieved through mass spectral electron ionization (EI) database matching at 70 eV (≥800/1000) and the Linear Retention Index (LRI) window within ±20, based on non-polar 1D-GC LRI data from the NIST database and literature. The location of the investigated molecules on the 2D-GC plane was also considered.