User`s guide

Sampling Techniques
334
Purge and Trap
One of the variations of vapor phase sampling is the purge and trap
technique. In this method, an inert gas is used to sweep volatile
components from solid or liquid matrices into the vapor phase. The
components are then concentrated on the sampling tube or tubes.
Figure 101 Open Loop Purging Apparatus with Removable
Adsorbent Tube
More information on purge and trap sampling is provided in The
Analysis of Volatile Organic Pollutants in Water and Sediment Using
Purge and Trap and Thermal Desorption, PerkinElmer Thermal
Desorption Applications Note 28 (TDA-28).
Soil Probes
Vapor phase monitoring can also be used for soil probes. An
example developed at British Petroleum Research is shown in
Figure 91. The probes are inserted into the ground and used to test
for leakage from landfill sites and fuel storage tanks, etc.
Adsorbent Tube
Optional
Line Heater
Water
Bath
Ultrapure Purge
Gas Supply
Sample
Sparger