title: Improved quantification of livestock associated odorous volatile organic compounds in a standard flow-through system using solid-phase microextraction and gas chromatography-mass spectrometry.
abstract: Aerial emissions of odorous volatile organic compounds (VOCs) are an important nuisance factor from livestock production systems. Reliable air sampling and analysis methods are needed to develop and test odor mitigation technologies. Quantification of VOCs responsible for livestock odor remains an analytical challenge due to physicochemical properties of VOCs and the requirement for low detection thresholds. A new air sampling and analysis method was developed for testing of odor/VOCs mitigation in simulated livestock emissions system. A flow-through standard gas generating system simulating odorous VOCs in livestock barn emissions was built on laboratory scale and tested to continuously generate ten odorous VOCs commonly defining livestock odor. Standard VOCs included sulfur VOCs (S-VOCs), volatile fatty acids (VFAs), and p-cresol. Solid-phase microextraction (SPME) was optimized for sampling of diluted odorous gas mixtures in the moving air followed by gas chromatography-mass spectrometry (GC-MS) analysis. CAR/PDMS 85μm fiber was shown to have the best sensitivity for the target odorous VOCs. A practical 5-min sampling time was selected to ensure optimal extraction of VFAs and p-cresol, as well as minimum displacement of S-VOCs. Method detection limits ranged from 0.39 to 2.64ppbv for S-VOCs, 0.23 to 0.77ppbv for VFAs, and 0.31ppbv for p-cresol. The method developed was applied to quantify VOCs and odorous VOC mitigation with UV light treatment. The measured concentrations ranged from 20.1 to 815ppbv for S-VOCs, 10.3 to 315ppbv for VFAs, and 4.73 to 417ppbv for p-cresol. Relative standard deviations between replicates ranged from 0.67% to 12.9%, 0.50% to 11.4%, 0.83% to 5.14% for S-VOCs, VFAs, and p-cresol, respectively. This research shows that a simple manual SPME sampler could be used successfully for quantification of important classes of odorous VOCs at concentrations relevant for real aerial emissions from livestock operations.
authors.affiliation: Department of Agricultural & Biosystems Engineering, Iowa State University, Ames, IA 50011-3080, USA.
authors.forename: Xiuyan
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Agricultural & Biosystems Engineering, Iowa State University, Ames, IA 50011-3080, USA; Interdepartmental Toxicology Program, Iowa State University, Ames, IA, USA.
authors.forename: Wenda
authors.initials: W
authors.lastname: Zhu
authors.affiliation: Department of Agricultural & Biosystems Engineering, Iowa State University, Ames, IA 50011-3080, USA; Department of Civil, Construction & Environmental Engineering, Iowa State University, Ames, IA, USA; Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA. Electronic address: koziel@iastate.edu.
authors.forename: Jacek A
authors.initials: JA
authors.lastname: Koziel
authors.affiliation: Department of Agricultural & Biosystems Engineering, Iowa State University, Ames, IA 50011-3080, USA.
authors.forename: Lingshuang
authors.initials: L
authors.lastname: Cai
authors.affiliation: Department of Chemistry, Iowa State University, Ames, IA, USA.
authors.forename: William S
authors.initials: WS
authors.lastname: Jenks
authors.affiliation: Agricultural Research Organization, Institute of Soil, Water and Environmental Sciences, Newe Ya'ar Research Center, Ramat-Yishay, Israel.
authors.forename: Yael
authors.initials: Y
authors.lastname: Laor
authors.affiliation: Department of Civil, Construction & Environmental Engineering, Iowa State University, Ames, IA, USA; Department of Agricultural & Biosystems Engineering, Iowa State University, Ames, IA 50011-3080, USA; Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA.
authors.forename: J Hans van
authors.initials: JH
authors.lastname: Leeuwen
authors.affiliation: Department of Agricultural & Biosystems Engineering, Iowa State University, Ames, IA 50011-3080, USA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Hoff
mesh_terms: D000818:Animals; D003408:Cresols / Q000032:analysis; D005232:Fatty Acids, Volatile / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D058751:Livestock; D009812:Odorants / Q000032:analysis; D052617:Solid Phase Microextraction / Q000379:methods; D055549:Volatile Organic Compounds / Q000032:analysis*
chemical_list: D003408:Cresols; D005232:Fatty Acids, Volatile; D055549:Volatile Organic Compounds; C032538:4-cresol
keywords: Air sampling; GC–MS; Odor; SPME; Standard gas generation system; VOCs