Characteristics of On-Line Membrane Extraction Microtrap GC System as Applied to Air and Water Monitoring

A method referred to as on-line membrane extraction microtrap gas chromatography (OLMEM) is presented for sampling organic pollutants directly into a gas chromatograph. This system is applicable for both air and water matrices. The sampling of the volatile organic compounds (VOCs) was achieved by passing water or air samples through a silicone hollow fiber membrane. An on-line microtrap was used to concentrate and inject the isolated organics into a GC. The extraction characteristics and optimum operating conditions for the membrane extraction of VOCs from air and water matrices were compared. Parameters such as response profile, extraction efficiency, analytical response at different flow rates, and effect of temperature variation were studied. Reynold's number was successfully used to normalize the viscosity and density differences between water and air.