Evaluation of Sample Recovery of Malodorous Gases from Air Sampling Bags, SPME, and Sampling Canisters

Odorous gases associated with livestock operations are complex mixtures of hundreds if not thousands of compounds. Research is needed to know how best to sample and analyze these compounds. The main objective of this research was to compare recoveries of a standard gas mixture of 11 odorous compounds from the Carboxen/PDMS 75 µm SPME fibers, PVF (Tedlar), FEP (Teflon), foil, and PET (Melinex) air sampling bags, and standard 6 L Stabilizer™ sampling canisters after sample storage at room temperature. A standard mixture consisted of 7 VFAs from acetic to hexanoic, and 4 semi-VOCs including p-cresol, indole, 4-ethylphenol, and 2’-aminoacetopheone with concentrations ranging from 5.1 ppb for indole to 1,270 ppb for acetic acid. On average, SPME had the highest mean recovery for all 11 gases of 106.2%, and 98.3% for 0.5 and 24 hrs sample storage time, respectively. This was followed by the PET bags (71.7% and 47.2%), FEP bags (75.4% and 39.4%), in-house-made Tedlar bags (47.3% and 37.4%), commercial Tedlar bags (67.6% and 22.7%), foil bags (16.4% and 4.3%), and canisters (4.2% and 0.5%), for 0.5 and 24 hrs, respectively. VFAs had higher recoveries than semi-VOCs for all bags and canisters. New FEP bags and new foil bags had the lowest and the highest amounts of chemical impurities, respectively. New commercial Tedlar bags had measurable concentrations of DMAC and phenol. Foil bags had measurable concentrations of acetic, propionic, butyric, valeric and hexanoic acids. Further research is warranted to determine how recoveries from bags affect odor concentrations as measured by olfactometry.