Vo. Elias et al., Detection of high molecular weight organic tracers in vegetation smoke samples by high-temperature gas chromatography-mass spectrometry, ENV SCI TEC, 33(14), 1999, pp. 2369-2376
Citations number
50
Categorie Soggetti
Environment/Ecology,"Environmental Engineering & Energy
High-temperature high-resolution gas chromatography (HTGC) is an establishe
d technique for the separation of complex mixtures of high molecular weight
(HMW) compounds which do not elute when analyzed on conventional GC column
s. The combination of this technique with mass spectrometry (i.e., HTGC-MS)
is not so common and application to aerosols is novel. The HTGC and HTGC-M
S analyses of smoke samples taken by particle filtration from combustion of
different species of plants provided the characterization of various class
es of HMW compounds reported to occur for the first time in emissions from
biomass burning. Among these components are a series of wax esters (long ch
ain alcohols esterified with long chain fatty acids) with up to 58 carbon n
umbers, aliphatic hydrocarbons (C-15-C-40; C-max = C-31; odd predominance),
triglycerides, long chain methyl ketones (up to 37 carbons; C-max = C-33;
odd predominance), alkanols (up to 40 carbons; C-max = C-32; even predomina
nce), and a series of triterpenyl fatty acid esters (e.g., alpha- and beta-
amyryl stearate) which have been characterized as novel natural products. L
ong chain fatty acids with more than 32 carbon numbers are not present in t
he smoke samples analyzed. The HMW compounds in smoke samples from the burn
ing of plants from Amazonia indicate the input of directly volatilized natu
ral products in the original plants during their combustion. However, the m
ajor organic compounds extracted from smoke consist of a series of lower mo
lecular weight polar components, which are not natural products but the res
ult of the thermal breakdown of cellulose and lignin. In contrast, the HMW
natural products may be suitable tracers for specific sources of vegetation
combustion because they are emitted as particles without thermal alteratio
n in the smoke and can thus be related directly to the original plant mater
ial.