HS-SPME-GC×GC ANALYSIS FOR VOCS PROFILING IN RECYCLED PLASTICS

In recent years, the growing concern surrounding plastic waste has led the European Commission to adopt increasingly stringent regulations, with the objective of promoting a circular economy, where materials are recovered, recycled and reintroduced into the production cycle and reducing environmental impact. Of particular interest are volatile organic compounds (VOCs), that represent a critical limitation in the revalorization and reuse of recycled plastics, especially when these materials are intended for new applications, for instance food packaging or in the automotive industry. In this work, plastic samples were analyzed using the emerging sample preparation technique solid phase microextraction (SPME). Specifically, analytes were extracted by HS-SPME and subsequently analyzed by comprehensive two-dimensional gas chromatography coupled with mass spectrometry (GC×GC-MS). This advanced analytical platform enables detailed characterization of complex polymer matrices, overcoming co-elution issues typical of one-dimensional GC and providing enhanced VOC fingerprinting. Two different extraction strategies were investigated to improve VOC characterization: single extraction and the multiple vials-multiple cumulative trap (MV-MCT) approach. Optimization studies were then carried out to evaluate the effect of sample mass and headspace extraction temperature on the efficient recovery of volatile and semi-volatile analytes. The extraction temperature was reduced to better approximate realistic environmental conditions and to more accurately simulate the development of off-flavors in recycled plastic materials. In conclusion, the MV-MCT approach coupled with GC×GC-MS was identified as the optimal method for the characterization of both virgin and recycled plastics. This combination highlights its suitability as a powerful screening tool for VOC assessment in recycled polymer materials.