There is increasing evidence that aqueous-phase atmospheric chemistry is an important source of secondary organic aerosols (SOA), but this chemistry is currently not adequately represented in atmospheric models due to the missing information on most products. The main focus of this study is to provide molecular-level insight into the photosensitized reaction mechanism of pyruvic acid (PA) alone in the atmospheric aqueous phase, and of mixtures of PA with glyoxal (GL), a typical and widely occurring carbonyl compound. With two ultrahigh resolution mass spectrometers, Orbitrap and FT-ICR-MS, a broad and complex spectrum of organic products were unambiguously identified. The detected formation of oligomers illustrates the progression from C3 to C20 molecules through direct PA photolysis and irradiation of PA + GL. The performed ab-initio calculations indicate that cross-reactions (i.e., PA + GL) are more likely than self-reactions (i.e., PA alone) in clouds and aerosol deliquescent particles. Hence, this result implies that photosensitizers like PA can initiate the transformation of common organic cloud constituents like GL into oligomers. These oligomeric products that are formed in significant amount could potentially impact optical and cloud-forming properties of aerosols, especially if they partition to the aerosol surface.

Formation of highly oxygenated multifunctional compounds from cross-reactions of carbonyl compounds in the atmospheric aqueous phase

Brigante M.;Vione D.;
2019

Abstract

There is increasing evidence that aqueous-phase atmospheric chemistry is an important source of secondary organic aerosols (SOA), but this chemistry is currently not adequately represented in atmospheric models due to the missing information on most products. The main focus of this study is to provide molecular-level insight into the photosensitized reaction mechanism of pyruvic acid (PA) alone in the atmospheric aqueous phase, and of mixtures of PA with glyoxal (GL), a typical and widely occurring carbonyl compound. With two ultrahigh resolution mass spectrometers, Orbitrap and FT-ICR-MS, a broad and complex spectrum of organic products were unambiguously identified. The detected formation of oligomers illustrates the progression from C3 to C20 molecules through direct PA photolysis and irradiation of PA + GL. The performed ab-initio calculations indicate that cross-reactions (i.e., PA + GL) are more likely than self-reactions (i.e., PA alone) in clouds and aerosol deliquescent particles. Hence, this result implies that photosensitizers like PA can initiate the transformation of common organic cloud constituents like GL into oligomers. These oligomeric products that are formed in significant amount could potentially impact optical and cloud-forming properties of aerosols, especially if they partition to the aerosol surface.
219
1
12
www.elsevier.com/locate/atmosenv
Atmospheric Chemistry; Cloud; Cross-Reactions; FT-ICR-MS; ORBITRAP; Photosensitizer; Sea Surface; SOA
Mekic M.; Liu J.; Zhou W.; Loisel G.; Cai J.; He T.; Jiang B.; Yu Z.; Lazarou Y.G.; Li X.; Brigante M.; Vione D.; Gligorovski S.
File in questo prodotto:
File Dimensione Formato  
Mekic et al .pdf

accesso aperto

Descrizione: Articolo principale
Tipo di file: PREPRINT (PRIMA BOZZA)
Dimensione 797.13 kB
Formato Adobe PDF
797.13 kB Adobe PDF Visualizza/Apri
Atmos_Environ_2019_carbonyl.pdf

non disponibili

Descrizione: Articolo principale
Tipo di file: PDF EDITORIALE
Dimensione 1.33 MB
Formato Adobe PDF
1.33 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2318/1724298
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 12
  • ???jsp.display-item.citation.isi??? 13
social impact