Characterization of Odorants in an Air Wet Scrubber Using Direct Aqueous Injection-Gas Chromatography-Mass Spectrometry (DAI-GC-MS) and Solid Phase Extraction (SPE-GC)

Abstract

One of the biological methods to reduce odours emission from livestock buildings is bioscrubber. Characterization (identification and quantification) of key odorants from an air wet scrubber in livestock buildings is presented. The key odorants represent five chemical groups, i.e. sulphides, alcohols, volatile fatty acids (VFAs), phenols and indoles. Direct aqueous injection (DAI) and solid phase extraction (SPE) methods were used for sample preparation before injecting the samples into the gas chromatography. Gas chromatography-flame ionization detection (GC-FID) was used for identification and quantification of samples prepared by DAI and SPE. The SPE method had a high recovery (i.e. 89-100%). However, DAI showed a better linearity, a lower limit of detection (LOD) and a lower limit of quantification (LOQ) than the SPE method. The DAI method was preferred for identification and quantification as it is cheaper, easier to handle, without sample preparation and highly applicable. For at least two odorants, i.e. phenol and 1-butanol, LOD and LOQ were below literature values for odorants detection limits in livestock buildings. Gas chromatography-mass spectrometry (GC-MS) was used to verify the identification of odorants, prepared by DAI, according to their m/z values.

Electronic tongue for determining the limit of detection of human pathogenic bacteria

“…The limit of detection (LOD) defines the lowest concentration of a variable in a sample that can be constantly detected by a particular measurement process at a specified level of confidence without the necessity of being quantitated as an exact value [29,30]. This research aims to evaluate and/or determine the limit for early detection (LOD) for both the number of colony-forming units (CFU) and incubation or growing periods of food-borne human pathogenic bacteria using ET and multivariate data analysis.…”

“…The limit of detection (LOD) defines the lowest concentration of a variable in a sample that can be constantly detected by a particular measurement process at a specified level of confidence without the necessity of being quantitated as an exact value [ 29 , 30 ].…”