Microplastics (MPs) are widespread environmental contaminants, and their weathering represents a major challenge for their analytical identification and quantification. Thermoanalytical techniques have become valuable tools for the qualitative and quantitative determination of MPs on a mass basis. Nevertheless, the influence of polymer ageing on their analytical performance remains poorly understood. This study addresses the impact of UV-induced ageing on the thermal degradation behaviour and analytical responses of four environmentally relevant polymers, poly(vinyl chloride) (PVC), poly(ethylene terephthalate) (PET), polystyrene (PS) and polyamide-6,6 (PA66), using evolved gas analysis-mass spectrometry (EGA-MS) and pyrolysis-gas chromatography--mass spectrometry (Py-GC-MS). Unaged and artificially aged true-to-life MPs were compared to evaluate changes in thermal behaviour, pyrolytic fingerprints, calibration responses and recovery after sample pretreatment based on Fenton oxidation and filtration. EGA-MS thermograms revealed polymer-dependent ageing effects, with PET and PVC maintaining stable thermal degradation profiles, PS exhibiting reduced thermal stability, and PA66 showing marked structural modification including a bimodal degradation profile. Py-GCMS confirmed that ageing preserved the characteristic pyrolytic fingerprints of PET, PVC and PS, whereas PA66 lost diagnostic nitrogen-containing pyrolysis markers, including hexamethylenediamine. UV ageing significantly affected the analytical sensitivity for PVC and PS, while recovery experiments showed polymer-dependent changes after sample pretreatment, with a decrease in analytical precision, indicating that ageing also influences particle behaviour during analytical workflows. These findings demonstrate that UV ageing can introduce systematic bias in both the qualitative and quantitative determination of MPs by analytical pyrolysis and highlight the need for environmentally representative test materials to improve reliability and harmonization of MP analysis.
Zulfiqar, H., Bonfante, F., Coralli, I., Ducoli, S., Federici, S., Rombola, A.G., et al. (2026). Effect of UV ageing on the analytical determination of microplastics by pyrolysis-GC-MS. MICROCHEMICAL JOURNAL, 230, 119715-119715 [10.1016/j.microc.2026.119715].
Effect of UV ageing on the analytical determination of microplastics by pyrolysis-GC-MS
Zulfiqar H.Primo
Writing – Original Draft Preparation
;Coralli I.
Data Curation
;Rombola A. G.Writing – Review & Editing
;Vassura I.Penultimo
Supervision
;Fabbri D.Ultimo
Conceptualization
2026
Abstract
Microplastics (MPs) are widespread environmental contaminants, and their weathering represents a major challenge for their analytical identification and quantification. Thermoanalytical techniques have become valuable tools for the qualitative and quantitative determination of MPs on a mass basis. Nevertheless, the influence of polymer ageing on their analytical performance remains poorly understood. This study addresses the impact of UV-induced ageing on the thermal degradation behaviour and analytical responses of four environmentally relevant polymers, poly(vinyl chloride) (PVC), poly(ethylene terephthalate) (PET), polystyrene (PS) and polyamide-6,6 (PA66), using evolved gas analysis-mass spectrometry (EGA-MS) and pyrolysis-gas chromatography--mass spectrometry (Py-GC-MS). Unaged and artificially aged true-to-life MPs were compared to evaluate changes in thermal behaviour, pyrolytic fingerprints, calibration responses and recovery after sample pretreatment based on Fenton oxidation and filtration. EGA-MS thermograms revealed polymer-dependent ageing effects, with PET and PVC maintaining stable thermal degradation profiles, PS exhibiting reduced thermal stability, and PA66 showing marked structural modification including a bimodal degradation profile. Py-GCMS confirmed that ageing preserved the characteristic pyrolytic fingerprints of PET, PVC and PS, whereas PA66 lost diagnostic nitrogen-containing pyrolysis markers, including hexamethylenediamine. UV ageing significantly affected the analytical sensitivity for PVC and PS, while recovery experiments showed polymer-dependent changes after sample pretreatment, with a decrease in analytical precision, indicating that ageing also influences particle behaviour during analytical workflows. These findings demonstrate that UV ageing can introduce systematic bias in both the qualitative and quantitative determination of MPs by analytical pyrolysis and highlight the need for environmentally representative test materials to improve reliability and harmonization of MP analysis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
