CHARACTERISTICS OF ONLINE MEMBRANE EXTRACTION MICROTRAP GC SYSTEM AS APPLIED TO AIR AND WATER MONITORING

A method referred to as on-line membrane extraction microtrap gas chro matography (OLMEM) is presented for sampling organic pollutants direct ly into a gas chromatograph. This system is applicable for both air an d water matrices. The sampling of the volatile organic compounds (VOCs ) was achieved by passing water or air samples through a silicone holl ow fiber membrane. An on-line microtrap was used to concentrate and in ject the isolated organics into a GC. The extraction characteristics a nd optimum operating conditions for the membrane extraction of VOCs fr om air and water matrices were compared. Parameters such as response p rofile, extraction efficiency, analytical response at different flow r ates, and effect of temperature variation were studied. Reynold's numb er was successfully used to normalize the viscosity and density differ ences between water and air. (C) 1996 John Wiley & Sons, Inc.