J. Swearingen, Jr. and T. G. Chasteen

Department of Chemistry
Sam Houston State University
Huntsville, Texas 77341-2117

Presented at the 58^th ACS Southwest Regional Meeting in Austin, Texas USA November 3-6, 2002.

Two methods for the analysis of the headspace of bacteria which release volatile organo-sulfur and organo-metalloidal compounds, Solid Phase Micro Extraction (SPME) and manual headspace extraction, were compared by the sensitivity of the method and the amount of time for analysis.  SPME analysis was carried out by using a 75 mm Carboxen-polydimethylsiloxane (CAR-PDMS) fiber.  Manual headspace gas extraction was carried out using a 1 mL gas syringe with locking valve. Gas chromatography/sulfur chemiluminescence detection was used to analyze organo-sulfur and organo-selenium compounds found in the bacterial headspace using the SPME fiber or syringe.  Fiber adsorption times and de-sorption times were tested with the SPME fiber in order to determine the most sensitive and quickest method for the analysis of headspace.  All syringe injections were held at a 1 mL volume. SPME was more sensitive in detection of bacterially produced organo-sulfur compounds under the conditions used.  The dominant sulfur compound detected by SPME after 24 and 48 hour bacterial growth periods was dimethyl disulfide, with some traces of dimethyl trisulfide in some cultures.  The quickest method in the analysis of bacterial headspace was manual headspace extraction, while the most sensitive method was SPME.