Characterization of Livestock Odors Using Steel Plates, Solid Phase Microextraction, and Multidimensional-Gas Chromatography-Mass Spectrometry-Olfactometry

Abstract

and Implications Livestock odor characterization is one of the most challenging analytical tasks. This is because odor-causing gases are often present at very low concentrations in a complex matrix of less important or irrelevant gases. The objective of this project was to develop a set of characteristic reference odors from a swine barn in Iowa, and in the process identify compounds causing characteristic swine odor. Odor samples were collected using a novel sampling methodology consisting of clean steel plates exposed inside and around the swine barn for up to one week. Steel plates were then transported to the laboratory and stored in clean jars. Headspace solid phase microextraction (SPME) was used to extract characteristic odorants collected on the plates. All analyses were conducted on a Gas Chromatography-Mass Spectrometry (GC-MS)-Olfactometry system where the human nose is used as a detector simultaneously with chemical analysis via MS. The effects of sampling time, distance from a source, and the presence of particulate matter (PM) on the abundance of specific gases, odor intensity, and odor character were tested. Steel plates were effectively able to collect key volatile compounds and odorants. The abundance of specific gases and odor was amplified when plates collected PM. The results of this research indicate that PM is major carrier of odor and several key swine odorants. Three odor panelists were consistent in identifying p-cresol as closely resembling characteristic swine odor as well as attributing the largest odor response out of the samples to p-cresol. Further research is warranted to determine how the control of PM emissions from swine housing could affect odor emissions.

Evaluation of Biological Air Filters for Livestock Ventilation Air by Membrane Inlet Mass Spectrometry

“…A number of methods based on gas chromatography coupled with mass spectrometric or flame photometric (sulfur‐specific) detection have been tested and applied for measurements of odorants from livestock facilities. These methods include sampling of air in canisters (Trabue et al, 2008a), on adsorption tubes for thermal desorption (Zahn et al, 1997; Hobbs et al, 1998; Schiffman et al, 2001; Adamsen et al, 2006; Kim et al, 2007; Trabue et al, 2008b), or on sorptive fibers for solid‐phase microextraction (Wright et al, 2005; Bulliner et al, 2006; Lo et al, 2008). Although significant progress has been achieved, no single quantitative method has been demonstrated to cover the full range of known odorous compounds present in air from livestock facilities.…”

Analytical Methods for Chemical and Sensory Characterization of Scent-Markings in Large Wild Mammals: A Review

“…A small split flow (∼10%) to the MS detector achieves correct timing to ensure target trapping in the loop which must be sufficiently cool to retain the trapped compounds of the target region [160]. Multidimensional GC-MS was applied to sensory and chemical characterization of odorous gases of swine manure and isolation of trans -resveratrol in red wine [89–91,96]. …”

Odour Detection Methods: Olfactometry and Chemical Sensors

“…Due to the high complexity of real odorous air samples, multidimensional GC is revealing a more powerful tool to allow a better livestock air resolution [42,108–111]. MDGC-O has also been employed to investigate the VOCs-odour-particular matter (PM) interactions, as suspended particulate is an important odour carrier [112].…”