A study of Analysis and Stability of Odor Compounds in Drinking Water using GC-MS

Abstract

Geosmin, 2-MIB and other 3 types of odor causing materials are naturally caused by soil bacteria which is called actinomyces or cyanobacteria. They are also known as that is able to odorize soil or mold in level of 5~8 ng/L. Even though they are non-maleficent, they need to be controlled because they are the first standard to determine the quality of drinking water. However, these odor compounds are semi-volatile and odor perceiving concentrations are very low. Thus it is difficult to perform the quantitative analysis. In variously extraction methods for the analysis of odor compounds, there are liquid-liquid extraction (LLE), purge & trap (P&T), solid-phase microextraction (SPME), solid-phase extraction (SPE). Among these analytical methods, LLE using pentane is a method in common use for the analysis in drinking water because of the low method detection limit (MDL) and less spending time. Before applying the LLE method to sample analysis the stability evaluation in sampling container was carried out. It shows that the analysis of odor compounds should be done in 15 days from taking samples. Especially, 2,4,5-TCA needs to be done quickly because its detection concentration is decreased dramatically during retention period after sampling.