ANYL 156 |
| Chemical analysis of organic aerosol using mass spectrometry and chromatography often involves extraction of filtered aerosol samples into a suitable solvent, commonly, methanol, water and acetonitrile. This study examined potential dissolution artifacts arising from solvent-analyte reactions. Secondary organic aerosol (SOA) resulted from ozonation of d-limonene and alpha-pinene as well as pure organic chemicals with functional groups commonly found in terpene-derived SOA were stored in methanol, d3-methanol, d3-acetonitrile, acetonitrile, and water to investigate the extent of reactions between analyte and solvent molecules. High resolution ESI-MS showed that reactions with methanol occur on a time scale of hours to days, with increased rate of reaction on addition of organic acid. In contrast, acetonitrile solutions show no reactions with analyte molecules regardless of solution acidity, suggesting acetonitrile as the optimal solvent for SOA extraction. Direct comparison between SOA samples in methanol and acetonitrile can be used to quantify the amounts of certain functional groups in SOA chemical constituents. Recommendations for sample preparation, concentration and storage time will be presented and discussed. |
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Environmental Chemistry
8:55 AM-11:55 AM, Tuesday, April 8, 2008 Morial Convention Center -- Rm. 335, Oral
Division of Analytical Chemistry |