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

Abstract

Odorous gases associated with livestock operations are complex mixtures of hundreds ifnot thousands of compounds. Research is needed to know how best to sample and analyze thesecompounds. The main objective of this research was to compare recoveries of a standard gasmixture of 11 odorous compounds from the Carboxen/PDMS 75 m SPME fibers, PVF (Tedlar), FEP(Teflon), foil, and PET (Melinex) air sampling bags, and standard 6 L Stabilizer sampling canistersafter sample storage at room temperature. A standard mixture consisted of 7 VFAs from acetic tohexanoic, and 4 semi-VOCs including p-cresol, indole, 4-ethylphenol, and 2-aminoacetopheone withconcentrations ranging from 5.1 ppb for indole to 1,270 ppb for acetic acid. On average, SPME hadthe highest mean recovery for all 11 gases of 106.2%, and 98.3% for 0.5 and 24 hrs sample storagetime, respectively. This was followed by the PET bags (71.7% and 47.2%), FEP bags (75.4% and39.4%), in-house-made Tedlar bags (47.3% and 37.4%), commercial Tedlar bags (67.6% and22.7%), 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 foilbags had the lowest and the highest amounts of chemical impurities, respectively. New commercialTedlar bags had measurable concentrations of DMAC and phenol. Foil bags had measurableconcentrations of acetic, propionic, butyric, valeric and hexanoic acids. Further research iswarranted to determine how recoveries from bags affect odor concentrations as measured byolfactometry.