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SAMPLING ARTIFACT ESTIMATES FOR ALKANES, HOPANES, AND ALIPHATIC CARBOXYLIC ACIDS
Citation:
SIHABUT, T., J. RAY, A. NORTHCROSS, AND S. R. MCDOW. SAMPLING ARTIFACT ESTIMATES FOR ALKANES, HOPANES, AND ALIPHATIC CARBOXYLIC ACIDS. ATMOSPHERIC ENVIRONMENT. Elsevier Science Ltd, New York, NY, 39(37):6948-6956, (2005).
Impact/Purpose:
1) Develop a TOA protocol that meets the basic assumptions of the method and peer review of the method, 2) understand the role of sampling, analysis, and blank subtraction on the differences between the IMPROVE and STN OC and EC results 3) Evaluate the use of light absorbance methods to estimate EC on human exposure samples, 4) develop a sensitive analytical method suitable for analysis of STN and micro-environmental samples for organic molecular markers, and 5) develop an optimum list of organic molecular markers for source apportionment of particulate matter.
Description:
Sampling artifacts for molecular markers from organic speciation of particulate matter were investigated by analyzing forty-one samples collected in Philadelphia as a part of the Northeast Oxidant and Particulate Study (NEOPS). Samples were collected using a high volume sampler with two quartz fiber filters in series. n-Alkanes (C23-C31), hopanes (C27-C31), and n-alkanoic acids (C10-C22) were analyzed by gas chromatography-mass spectrometry (GCMS). The extent of artifact error was dependent on vapor pressure and species concentration. Particulate organic species are classified into the following three categories: 1) the amount collected on the backup filter was often a large fraction of the amount collected on the front filters (n-alkanes C23 and C24, n-carboxylic acids C10 to C14); 2) the amount collected on the backup filter was consistently a small fraction of the amount collected on the front filter (n-alkanes C25 to C28, hopanes C27 to C30, n-carboxylic acids C15 to C18, and dicarboxylic acids C3 to C9); 3) the species was rarely observed on backup filters (n-alkanes C29 to C31, hopanes C31 and C32).