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Gas chromatography (GC) is a common type of chromatography used in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition. Typical uses of GC include testing the purity of a particular substance, or separating the different components of a mixture. [ 1 ]
Pyrolysis–gas chromatography–mass spectrometry is a method of chemical analysis in which the sample is heated to decomposition to produce smaller molecules that are separated by gas chromatography and detected using mass spectrometry. Pyrolysis is the thermal decomposition of materials in an inert atmosphere or a vacuum.
Gas chromatograms of mature oils have prominent n-alkane peaks which distract attention from the underlying unresolved complex mixture (UCM) of hydrocarbons often referred to as the ‘hump’. Processes such as weathering and biodegradation result in a relative enrichment of the UCM component by removal of resolved components and the creation ...
The target analytes are extracted by mixing the sample with water and purge with inert gas (e.g. Nitrogen gas) into an airtight chamber, this is known as purging or sparging. The volatile compounds move into the headspace above the water and are drawn along a pressure gradient (caused by the introduction of the purge gas) out of the chamber.
Others introduced mass spectrometers to gas chromatography in the late 1950s. [29] The work of Martin and Synge also set the stage for high performance liquid chromatography, suggesting that small sorbent particles and pressure could produce fast liquid chromatography techniques. This became widely practical by the late 1960s (and the method ...
John Knox was an early leader in the field of gas chromatography. As a PhD student in at Pembroke College, Cambridge, [3] in 1953 Knox, together with his fellow student Howard Purnell, constructed a self-designed gas chromatographer in their lab and used this to pioneer early research in the field. In later experiments Knox was the first to use ...
In other types of chromatography with a solid stationary phase, such as thin-layer chromatography the analyte is selectively adsorbed onto the solid. In gas–liquid chromatography (GLC) the stationary phase is a liquid such as polydimethylsiloxane, coated on a glass tube. Separation is achieved because the various components in the gas have ...
Chromatography columns of different types are used in both gas and liquid chromatography: Liquid chromatography: Traditional chromatography columns were made of glass. Modern columns are mostly made of borosilicate glass, acrylic glass or stainless steel. To prevent the stationary phase from leaking out of the column interior a polymer ...