TY - JOUR
T1 - Evidence for oligomer formation in clouds
T2 - Reactions of isoprene oxidation products
AU - Altieri, Katye E.
AU - Carlton, Annmarie G.
AU - Lim, Ho Jin
AU - Turpin, Barbara J.
AU - Seitzinger, Sybil P.
PY - 2006/8/15
Y1 - 2006/8/15
N2 - Electrospray ionization mass spectrometry (ESI-MS) was used to investigate product formation in laboratory experiments designed to study secondary organic aerosol (SOA) formation in clouds. It has been proposed that water soluble aldehydes derived from aromatics and alkenes, including isoprene, oxidize further in cloud droplets forming organic acids and, upon droplet evaporation, SOA. Pyruvic acid is an important aqueous-phase intermediate. Time series samples from photochemical batch aqueous phase reactions of pyruvic acid and hydrogen peroxide were analyzed for product formation. In addition to the monomers predicted by the reaction scheme, products consistent with an oligomer system were found when pyruvic acid and OH radical were both present. No evidence of oligomer formation was found in a standard mix composed of pyruvic, glyoxylic, and oxalic acids prepared in the same matrix as the samples analyzed using the same instrument conditions. The distribution of high molecular weight products is consistent with oligomers composed of the mono-, oxo-, and di-carboxylic acids expected from the proposed reaction scheme.
AB - Electrospray ionization mass spectrometry (ESI-MS) was used to investigate product formation in laboratory experiments designed to study secondary organic aerosol (SOA) formation in clouds. It has been proposed that water soluble aldehydes derived from aromatics and alkenes, including isoprene, oxidize further in cloud droplets forming organic acids and, upon droplet evaporation, SOA. Pyruvic acid is an important aqueous-phase intermediate. Time series samples from photochemical batch aqueous phase reactions of pyruvic acid and hydrogen peroxide were analyzed for product formation. In addition to the monomers predicted by the reaction scheme, products consistent with an oligomer system were found when pyruvic acid and OH radical were both present. No evidence of oligomer formation was found in a standard mix composed of pyruvic, glyoxylic, and oxalic acids prepared in the same matrix as the samples analyzed using the same instrument conditions. The distribution of high molecular weight products is consistent with oligomers composed of the mono-, oxo-, and di-carboxylic acids expected from the proposed reaction scheme.
UR - http://www.scopus.com/inward/record.url?scp=33747512157&partnerID=8YFLogxK
U2 - 10.1021/es052170n
DO - 10.1021/es052170n
M3 - Article
C2 - 16955892
AN - SCOPUS:33747512157
SN - 0013-936X
VL - 40
SP - 4957
EP - 4960
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 16
ER -