The SRI Method TO-14 air concentrator is identical to the Method 5030 style Purge & Trap, but without the liquid purge vessel.  The purge vessel is replaced with a vacuum pump interface so an external vacuum pump may be attached to the downstream side of the traps to automatically load a gas sample under control of the PeakSimple data system.  Gas samples may be contained in tedlar bags, canisters or may be sampled directly from the source. 

The vacuum pump is operated for several minutes or more to pass 100-200 ml/minute of gas through the traps where the organics are retained. Several liters or more may be concentrated depending on the ultimate detection limit required. 

An optional off-line tube desorber may be added to the concentrator for applications where the sample is already trapped off-line on charcoal, Tenax or molesieve sampling tubes. The off-line tube is connected to a heater block and purge gas fittings mounted on the top of the concentrator.  Under control of the PeakSimple data system ( for reproducibility ) the tube is heated and its contents flushed into the traps of the concentrator.  This process can take several minutes depending on the trapping material in the tube.  The re-trapped organic analytes are then efficiently desorbed onto the GC column for separation and quantitation.