Headspace Analysis - Mass Spectroscopy

Headspace analysis is a method of choice for the determination of volatile compoimds in polymers. The principle of the analysis is quite simple. The sample is placed in a container leaving a large headspace, which is filled with an inert gas (sometimes under pressure) that also serves as the gas chromatography (GC) carrier gas. Under the prevailing equilibrium conditions a proportion of the volatiles in the sample transfers to the gas-filled headspace, which is then withdrawn and analysed by GC. [Pg.165]

A glass ignition tube is supported as shown in a 0.8 cm diameter brass coupling unit. [Pg.165]

The sample tube is then heated in the copper block under the required conditions of time and temperature. A sample of the headspace gas is withdrawn from the ignition tube into a Hamilton gas-tight hypodermic syringe via the septum and injected into aGC. [Pg.165]

Purge and trap analysis is an alternative technique to headspace analysis for the identification and determination of volatile organic compoimds in polymers. The sample is swept with an inert gas for a fixed period of time. Volatile compounds from the sample are collected on a solid sorbent trap - usually activated carbon. Tbe trap is then rapidly heated and the compounds collected and transferred as a ping nnder a reversed flow of inert gas to an external GC. Chromatographic techniqnes are then used to quantify and identify sample components. [Pg.165]

In instances where the chemical identity of some or all of the volatiles present in a polymer are not known it is possible to obtain the required information by the application of this technique. Thus, workers at Hewlett Packard [3] used headspace analysis mass spectroscopy (MS) to identify six volatiles in styrene-acrylonitrile-maleic anhydride teropolymer (benzene, toluene, ethylbenzene, styrene, aromatics, and maleic anhydride). [Pg.165]

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