Evaluation of storage bags for odour sampling from intensive pig production measured by proton-transfer-reaction mass-spectrometry

摘要

The selection of sampling bags for odour measurement by olfactometry is critical and challenging since the loss of odorants during storage and transportation is usually high. However, there are no recommendations or limitations on the storage time for the standard Triangle odour bag method used in China. In order to optimise the selection of sampling bags, selected types of sampling bags (Fluode, BOPET, FEP and Tedlar) were tested and compared by using selected key odorants (dimethyl sulphide, 2-butanone, 2,3-butanedione, 4-methylphenol, indole, skatole, acetic acid, propanoic acid, butyric acid, valeric acid and hexanoic acid). The concentrations of key odorants were detected by PTR-MS. Firstly, background contamination was tested, with total amount of background pollutants produced by Tedlar being significantly higher than the other three types of sampling bags, while FEP and BOPET had less background contaminants. Secondly, recovery tests showed that the SOAV (sum of odour activity values) recoveries after 24 h of storage of Fluode, Tedlar, FEP and BOPET were 19.5%, 24.2%, 47.7% and 27.7%, respectively. FEP had better recovery than others, especially for the storage of 4-methylphenol (similar to 55% recovery after 48 h), which is one of the key odorants emitted from intensive pig production. Finally, the recovery tests for 2,3-butanedione were performed under various conditions and results indicated that the storage of 2,3-butanedione in sampling bags depends on bag type (e.g. single bags or double bags), initial concentration level (10 ppbv, 100 ppbv or 1000 ppbv), the inner surface area-to-volume ratio and light condition (dark, natural light or LED light). (C) 2019 IAgrE. Published by Elsevier Ltd. All rights reserved.