Instrument: 3100 Purge and Trap Sample Concentrator
Fundamentals of Purge and Trap
Purge and Trap has been used for decades to extract volatile organic compounds (VOCs) from a solid or liquid matrix for introduction into a Gas Chromatograph (GC) for separation and identification. The VOCs are concentrated onto an absorbent trap, followed by thermal desorption into a GC. Sample matrices can range from soil, plastics, foods, flavor, fragrance, emulsions and water.
From its early body fluids' applications in the 1960's, Purge and Trap has evolved to the standardized protocol for analyzing environmental samples (i.e., soil, water). Several regulatory agencies including the United States Environmental Protection Agency (USEPA), the United States Department of Energy (USDOE), and the United States Department of Defense (USDOD) has instituted methodologies based on Purge and Trap.
The Tekmar 3000 purge and trap concentrator has been designed to perform these functions. The Purge and Trap concentrator is interfaced to a GC through its injection port or directly to the column based on the configuration desired. The purge gas is supplied directly on the concentrator and is flow regulated before purging the sample. The desorption gas is supplied and controlled by the GC or a separate regulator. These gas flows are routed through the concentrator by solenoids and a six port switching valve.
The Purge and Trap primarily performs three functions: Purge, Desorb, and Trap Bake. A detail description of the operation of the system is outlined below.
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