Testing odorants recovery from a novel metallized fluorinated ethylene propylene gas sampling bag

Wenda Zhu,Jacek A Koziel,Lingshuang Cai,Donald Wright,Fred Kuhrt

doi:10.1080/10962247.2015.1100142

Wenda Zhu, Jacek A Koziel + Show 3 more

Open Access

https://doi.org/10.1080/10962247.2015.1100142

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Abstract

Industry-standard Tedlar bags for odor sample collection from confined animal feeding operations (CAFOs) have been challenged by the evidence of volatile organic compound (VOC) losses and background interferences. Novel impermeable aluminum foil with a thin layer of fluorinated ethylene propylene (FEP) film on the surface that is in contact with a gas sample was developed to address this challenge. In this research, Tedlar and metallized FEP bags were compared for (a) recoveries of four characteristic CAFO odorous VOCs (ethyl mercaptan, butyric acid, isovaleric acid and p-cresol) after 30 min and 24 hr sample storage time and for (b) chemical background interferences. All air sampling and analyses were performed with solid-phase microextraction (SPME) followed by gas chromatography–mass spectroscopy (GC-MS). Mean target gas sample recoveries from metallized FEP bags were 25.9% and 28.0% higher than those in Tedlar bags, for 30 min and 24 hr, respectively. Metallized FEP bags demonstrated the highest p-cresol recoveries after 30-min and 24-hr storage, 96.1 ± 44.5% and 44.8 ± 10.2%, respectively, among different types of sampling bags reported in previous studies. However, a higher variability was observed for p-cresol recovery with metallized FEP bags. A 0% recovery of ethyl mercaptan was observed with Tedlar bags after 24-hr storage, whereas an 85.7 ± 7.4% recovery was achieved with metallized FEP bags. Recoveries of butyric and isovaleric acids were similar for both bag types. Two major impurities in Tedlar bags’ background were identified as N,N-dimethylacetamide and phenol, while backgrounds of metallized FEP bags were significantly cleaner. Reusability of metallized FEP bags was tested.Implications: Caution is advised when using polymeric materials for storage of livestock-relevant odorous volatile organic compounds. The odorants loss with storage time confirmed that long-term storage in whole-air form is ill advised. A focused short-term odor sample containment should be biased toward the most inert material available relative to the highest impact target odorant. Metallized FEP was identified as such a material to p-cresol as the highest impact odorant from confined animal feeding operations. Metallized FEP bags have much cleaner background than commercial Tedlar bags do. Significantly higher recoveries of methyl mercaptan and p-cresol were also observed with metallized FEP bags.

Highlights

In recent decades, intensive large-scale livestock production has grown rapidly in the U.S and other parts of the world
Metalized fluorinated ethylene propylene (FEP) bags had a significantly cleaner background than that of Tedlar bags which were contaminated with considerable amounts of DMAC and phenol as well as other interferences containing Si m/z signature ions originating from silicon septum material
The phenol and DMAC identified from Tedlar bag background emissions can potentially cause interference to confined animal feeding operation (CAFO) odorant assessment and olfactory data

Summary

Introduction

Intensive large-scale livestock production has grown rapidly in the U.S and other parts of the world. Increasing number of studies show that only a relatively small subset of VOCs such as p-cresol and selected phenolics/indolics, volatile fatty acids, and sulfur VOCs is responsible for the characteristic livestock odor (Wright et al, 2005; Bulliner et al, 2006; Koziel et al, 2006; Laor et al, 2008). Most of these odorcausing VOCs are polar, reactive, and highly sorptive onto surfaces of sampling media which increases the challenge for their measurement. Air was stored in each bag for either 30 min or 24 hr storage time at room temperature and analyzed

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