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DETECTION OF HIGH MOLECULAR WEIGHT ORGANIC TRACERS IN VEGETATION SMOKE SAMPLES BY HIGH-TEMPERATURE GAS CHROMATOGRAPHY-MASS SPECTROMETRY. (R823990)
Citation:
Elias, V. O., B. R. Simoneit, A. S. Pereira, J. A. Cabral, AND J. N. Cardoso. DETECTION OF HIGH MOLECULAR WEIGHT ORGANIC TRACERS IN VEGETATION SMOKE SAMPLES BY HIGH-TEMPERATURE GAS CHROMATOGRAPHY-MASS SPECTROMETRY. (R823990). ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 33(14):2369-2376, (1999).
Description:
High-temperature high-resolution gas chromatography
(HTGC) is an established technique for the separation of
complex mixtures of high molecular weight (HMW) compounds
which do not elute when analyzed on conventional GC
columns. 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-MS analyses of smoke samples taken by particle filtration
from combustion of different species of plants provided
the characterization of various classes 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 chain alcohols esterified with long chain
fatty acids) with up to 58 carbon numbers, aliphatic
hydrocarbons (C15-C40; Cmax = C31; odd predominance),
triglycerides, long chain methyl ketones (up to 37 carbons;
Cmax = C33; odd predominance), alkanols (up to 40
carbons; Cmax = C32; even predominance), and a series of
triterpenyl fatty acid esters (e.g., 
- and 
-amyryl stearate)
which have been characterized as novel natural products.
Long chain fatty acids with more than 32 carbon numbers
are not present in the smoke samples analyzed. The HMW
compounds in smoke samples from the burning of plants
from Amazonia indicate the input of directly volatilized natural
products in the original plants during their combustion.
However, the major organic compounds extracted from
smoke consist of a series of lower molecular weight polar
components, which are not natural products but the
result 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
alteration in the smoke and can thus be related directly
to the original plant material.