Characterization of organosulfates from the photooxidation of isoprene and unsaturated fatty acids in ambient aerosol using liquid chromatography/(-) electrospray ionization mass spectrometry.
In the present study, we have characterized in detail the MS(2) and MS(3) fragmentation behaviors, using electrospray ionization (ESI) in the negative ion mode, of previously identified sulfated isoprene secondary organic aerosol compounds, including 2-methyltetrols, 2-methylglyceric acid, 2-methyltetrol mononitrate derivatives, glyoxal and methylglyoxal. A major fragmentation pathway for the deprotonated molecules of the sulfate esters of 2-methyltetrols and 2-methylglyceric acid and of the sulfate derivatives of glyoxal and methylglyoxal is the formation of the bisulfate [HSO(4)](-) anion, while the deprotonated sulfate esters of 2-methyltetrol mononitrate derivatives preferentially fragment through loss of nitric acid. Rational interpretation of MS(2), MS(3) and accurate mass data led to the structural characterization of unknown polar compounds in K-puszta fine aerosol as organosulfate derivatives of photooxidation products of unsaturated fatty acids, i.e. 2-hydroxy-1,4-butanedialdehyde, 4,5- and 2,3-dihydroxypentanoic acids, and 2-hydroxyglutaric acid, and of alpha-pinene, i.e. 3-hydroxyglutaric acid. The deprotonated molecules of the sulfated hydroxyacids, 2-methylglyceric acid, 4,5- and 2,3-dihydroxypentanoic acid, and 2- and 3-hydroxyglutaric acids, showed in addition to the [HSO(4)](-) ion (m/z 97) neutral losses of water, CO(2) and/or SO(3), features that are characteristic of humic-like substances. The polar organosulfates characterized in the present work are of climatic relevance because they may contribute to the hydrophilic properties of fine ambient aerosol. In addition, these compounds probably serve as ambient tracer compounds for the occurrence of secondary organic aerosol formation under acidic conditions.
Gómez-González
Yadian
Y
Department of Pharmaceutical Sciences, University of Antwerp (Campus Drie Eiken), Universiteitsplein 1, BE-2610 Antwerp, Belgium.
Surratt
Jason D
JD
Cuyckens
Filip
F
Szmigielski
Rafal
R
Vermeylen
Reinhilde
R
Jaoui
Mohammed
M
Lewandowski
Michael
M
Offenberg
John H
JH
Kleindienst
Tadeusz E
TE
Edney
Edward O
EO
Blockhuys
Frank
F
Van Alsenoy
Christian
C
Maenhaut
Willy
W
Claeys
Magda
M
D000336:Aerosols / Q000737:chemistry*; D000393:Air Pollutants / Q000032:analysis* / Q000138:chemical synthesis / Q000737:chemistry; D000447:Aldehydes / Q000032:analysis; D002070:Butadienes / Q000737:chemistry*; D002853:Chromatography, Liquid / Q000379:methods; D005231:Fatty Acids, Unsaturated / Q000737:chemistry*; D005977:Glutarates / Q000032:analysis; D045782:Hemiterpenes / Q000737:chemistry*; D015394:Molecular Structure; D009589:Nitrogen Oxides / Q000737:chemistry; D010420:Pentanes / Q000737:chemistry*; D010421:Pentanoic Acids / Q000032:analysis; D010777:Photochemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013458:Sulfur Dioxide / Q000737:chemistry; D013463:Sulfuric Acid Esters / Q000032:analysis* / Q000737:chemistry
D000336:Aerosols; D000393:Air Pollutants; D000447:Aldehydes; D002070:Butadienes; D005231:Fatty Acids, Unsaturated; D005977:Glutarates; D045782:Hemiterpenes; D009589:Nitrogen Oxides; D010420:Pentanes; D010421:Pentanoic Acids; D013463:Sulfuric Acid Esters; C005059:isoprene; D013458:Sulfur Dioxide