Gas Chromatography-Atmospheric Pressure Chemical Ionization (GC-APCI) Expands the Analytical Window for Detection of Large PAHs (≥24 Ringed-Carbons) in Pyroplastics and Other Environmental Matrices.

Open waste burning, large-scale fires, and maritime disasters produce partially burnt plastic called "pyroplastic". Chemical markers would provide a complementary method to appearance and physical properties for identifying pyroplastics in environmental samples, particularly with respect to microplastics. Pyroplastic can contain significant quantities and unique distributions of parent polycyclic aromatic hydrocarbons (PAHs) with molecular weights up to 278 Da. Because of this enrichment, we considered whether large PAHs (≥24 ringed-carbons) could serve as chemical markers for pyroplastics. To address this, we developed a high-temperature method for gas chromatography atmospheric pressure chemical ionization (GC-APCI) coupled with tandem mass spectrometry (MS/MS) to target large PAHs with molecular weights ranging from 314-424 Da. Method development was performed using National Institute of Standards and Technology standard reference materials (SRMs) previously characterized for PAHs greater than 302 Da. A PAH class-specific MS/MS acquisition scheme combined with a simple, generic microextraction provided sensitive and specific detection without the need for sample fractionation or cleanup. Pyroplastics collected during the 2021 M/V