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Submitted to: Proceedings of the Workshop on Agricultural Air Quality: State of the Science
Publication Type: Proceedings Publication Acceptance Date: 6/8/2006 Publication Date: 6/8/2006 Citation: Trabue, S.L., Scoggin, K.D. 2006. Measurement of volatile sulfur compounds associated with animal feeding operations. Proceedings Workshop on Agricultural Air Quality: State of the Science, June 5-8, 2006, Potomac, Maryland. p. 227-232. . Interpretive Summary: Volatile sulfur compounds (VSC) are an important component of odor due to their low odor threshold values. These compounds have been identified as the dominant odorants emitted from both municipal sewage systems and pulp and paper mill facilities, and they are believed to contribute significantly to odor at animal feeding operations (AFO). Hydrogen sulfide is typically thought of as the main offender in terms of odor, but recently this assumption has been challenged by other researchers. We have developed a new method that uses mini-canisters to sample whole air and analyze it on our gas chromatogram (GC) with both a mass spectrometer (MSD) and pulse flame photometric detectors (PFPD). The PFPD is a sulfur specific detector and helps us to locate sulfur compounds in our whole chromatogram, while the MSD allows us to identify the sulfur compounds associated with peaks on the PFPD. This method was used in the field at a swine, poultry, and dairy facilities. This method helped us to not only identfy hydrogen sulfide but enable us to identify and quantify carbonyl sulfide, carbon disulfide, dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, and methanethiol. Development of this method will enable researchers and livestock producers the ability to measure VSC accurately in the ambient air (in and around AFO) and to determine the effect VSC have on air quality. Technical Abstract: Volatile sulfur compounds (VSC) are a major class of chemicals associated with odor from animal feeding operations. Identifying and quantifying VSC in air is challenging due to their volatility, reactivity, and low concentrations. In this study, a canister based method is presented that allowed for the analysis of VSC in ambient air at the sub-part-billion range. This technique used whole air sampling with fused silica lined (FSL) mini-canisters (1.4 L). Canisters were sampled using a heated robotic autosampler which are cryofocused onto the GC column and subsequently analyzed in parallel with a MS (mass spectrometer) and PFPD (pulsed flame photometric detector). The GC column effluent was split 20:1 between the MS and PFPD. The PFPD equimolar sulfur response enhanced quantitation and the location of sulfur peaks for mass spectral identity. However, transfer of VSC in the canister GC system was not uniform as evidenced by magnitude of calibration slopes equimolar responses. Results from air samples taken from dairy, poultry and swine operations allowed for the identification and quantification of hydrogen sulfide, carbonyl sulfide, carbon disulfide, dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide. |
