Field-portable solid-phase microextraction/fast GC system for trace analysis†

Abstract

A commercially available SRI gas chromatograph (model 9300B) has been adapted to enable the use of solid phase microextraction (SPME) as the sample preparation and introduction technique for fast GC separations in the field. SPME utilizes a small-diameter fused silica fiber coated with a polymeric stationary phase for extraction of organic analytes from aqueous or gaseous matrices. The analytes extracted are thermally desorbed in the injector of a gas chromatograph. Modifications to the instrument included a new injector and modifications to the PID detector. The injector enables very fast fiber heating rates (∼4000 °C/s), which produce narrow injection bands suitable for fast GC. Separation of BTEX (100 ppb each compound) within 15 s has been demonstrated with FID and PID detection. The precision of the results was very good. Separation of purgeables (trichlorofluoromethane, 1,1-dichloroethene, dichloromethane, 1,1-dichloroethane, trichloromethane, tetrachloromethane, trichloroethene, 1,2-dichloropropane, 2-chloroethyl vinyl ether, 1,1,2-trichloroethane, tetrachloroethene, dibromochloromethane, chlorobenzene; 200 ppb each compound) was accomplished in 2 min with good precision with the use of a dry electrolytic conductivity detector (DELCD). The instrument was tested in the field in the analysis of trichloroethylene in soil extracts. PID was used for detection because its dynamic range is better as compared to DELCD. Almost 500 samples were analyzed in 10 days without major problems. © 1997 John Wiley & Sons, Inc. Field Analyt Chem Technol 1: 277–284, 1997