Headspace sampling techniques sorbent trapping

This is an alternative technique to headspace analysis for the identification and determination of volatile organic compounds in water. The sample is purged with an inert gas for a fixed period of time. Volatile compounds are sparged from the sample and collected on a solid sorbent trap—usually activated carbon. The trap is then rapidly heated and the compounds collected and transferred as a plug under a reversed flow of inert gas to an external gas chromatograph. Chromatographic techniques are then used to quantify and identify sample components. 

The static and dynamic headspace techniques are the most common techniques for determination of volatile analytes from aqueous samples. In the latter, also called purge-and-trap, a gas is passed over the sample or through the sample as small bubbles and the volatile compounds in the sample are transported by the gas to a cryogenic or a sorbent trap, before subsequent GC separation. In the more common static headspace technique, the sample vial is thermostated (Figure 2.5) until... 

Purge and trap (P T), so called d)mamic headspace, could be defined as a headspace gas analysis in which volatiles are stripped from the sample with an inert gas, trapped into a solid sorbent, and thermally desorbed into a gas chromatograph (for applications see Table 23.2). Since the first attempts by Swinnerton and Linnebom in 1967 and the development of the popular system pioneered by Bellar and Lichtenberg [98], P T has been widely used in environmental analysis for volatile organic pollutants in water [70,98-113] and has been extended to foods [114], clinical applications [115], and other matrices [116-117]. P T is the most widely used technique for the routine quality control of organic volatiles in any kind of water and is the official method required in many coimtries. 

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