Date of Award
Master of Science
Agricultural and Biosystems Engineering
Swine operations are associated with emissions of odor, volatile organic compounds (VOCs) and other gases. One of the major sources of VOCs and odor is the manure. However, relatively little is known about VOCs and gases emitted and their relationship to the malodor. It is critical to characterize swine manure VOCs and malodorous gases to improve the understanding of the environmental impact of swine operations. This knowledge is also needed to develop and evaluate odor and gas emission strategies and technologies. In this research, solid phase microextraction (SPME) and multidimensional gas chromatography-mass spectrometry-olfactometry (MDGC-MS-O) system were used to identify VOCs and other gases emitted from swine manure. This analytical system enabled simultaneous chemical and sensory analyses of air samples. Manure was collected and transferred into individual vials in the laboratory. Gas samples were extracted from vial headspace using Carboxen/Polydimethylsiloxane (PDMS) 85 [Mu]m SPME fibers and were analyzed using the MDGC-MS-0 system. Twenty-four-hour SPME extractions were used to improve the detection limits for semi-volatile organics and compounds with small affinity to SPME fiber coating. The MDGC-MS-0 system was equipped with two columns in series with a system of valves allowing transfer of samples between columns (heartcutting). Thirty-second-wide heartcuts were used to maximize the isolation, separation and identification of compounds emitted from swine manure. The odor impact of separated compounds was evaluated by a trained panelist using the sniff port and Aromatrax odor characterization software. Odor was evaluated for character and intensity. A total of 295 compounds with molecular weights ranging from 34 (H2S) to 260 (1-chloro-hexadecane) were identified using analytical software BenchTop/PBM and MS ChemStation. One hundred and thirteen were positively confirmed with pure standards. Seventy one of the 295 compounds had a distinct odor/aroma and several had a strong impact on the characteristic swine odor. The correlations between compounds emitted from swine manure and their physicochemical properties were studied. Carbon number, boiling point, vapor pressure, water solubility, octanol-water partitioning coefficient (logK[subscript ow]), atmospheric lifetime ([Tau]) based on reactions with OH· radicals, gas-phase molecular diffusion coefficient (D[subscript g]), liquid-phase molecular diffusion coefficient (D1), Henry's law constant (H[subscript c]) and odor characteristics were summarized.
Yin-Cheung Miranda Lo
Lo, Yin-Cheung Miranda, "Simultaneous chemical and sensory characterization of VOCs and semi-VOCs emitted from swine manure using SPME and multidimensional gas chromatography-mass spectrometry-olfactometry system" (2006). Retrospective Theses and Dissertations. 19332.