Purge‐and‐Trap Extraction of Geosmin and 2‐Methylisoborneol from Soil

Abstract

AbstractAlthough a number of techniques are available for estimating the biomass of filamentous microorganisms in soil, determination of their activity is much more difficult. We report on preliminary studies evaluating the potential use of the volatile microbial secondary metabolites geosmin and methylisoborneol as indicators of activity of filamentous microorganisms. The purge‐and‐trap technique for analysis of low concentrations of volatile organic compounds in air and water was tested for extracting the earthy‐musty odor compounds geosmin and 2‐methylisoborneol from soil. Two variations of this method were tried, one in which soil samples were placed in water for purging and another in which samples were purged with no added water. Volatile organic compounds purged from soil were collected on a porous polymer sorbent, Tenax TA. Naturally occurring geosmin and 2‐methylisoborneol and added standards were successfully extracted from soil by both methods. Recovery efficiencies, however, were low. Results indicated that wet purging was the most efficacious extraction method yielding maximum recovery rates of added geosmin and 2‐methylisoborneol standards of 15 and 24%, respectively.