Fractionation of offensive odorous substances in a Pig’s feces by gel permeation chromatography (GPC)

Abstract

GC-MS was used to detect substances of the offensive odor. And it was very difficult to understand the main substances which contribute the offensive odor in the eluted solution by the analysis of GC-MS peaks, because the offensive odor was constituted from many kinds of odorous substances.

In this research, gel permeation chromatography (GPC) was used to fractionate the extracted solution of pig’s feces at every 10ml, and odor test and GC-MS analysis were conducted for each fraction. The substances having high boiling temperature in the pig’s feces were targeted because those remain much offensive odor compare to the volatile substances. The thresholds of twelve odorous substances were determined, and the converted value of each odorous substance was obtained by dividing the concentration of the odorous substance by the threshold respectively.

The contribution of each odorous substance to offensive odor was evaluated by analyzing the change of characteristic odor and converted values of odorous substances in the GPC eluted fraction. Skatole showed the strongest contribution to the offensive odor and the contribution decreased in the odor of isopentanoic acid, 3-phenylpropanoic acid, p-cresol, n-butyric acid, n-pentanoic acid, indol, propanoic acid, n-hexanoic acid, isobutyric acid, and phenol. Odor strength of phenylacetic acid was thought to be high, but not calculated the converted value of odorous substances because of absence of the standard material.