Authors / CoAuthors
Sandison, C.M. | Alexander, R. | Kagi, R.I.
Abstract
The technique of Reaction Gas Chromatography-Mass Spectrometry (R-GCMS) has been applied to the analysis of the polar extracts from a Heartbreak Ridge lignite (Bremer Basin, Western Australia; Eocene age) and a Monterey Formation shale (Naples Beach, USA; Miocene age). A catalyst, palladium black, is packed into glass liners for split vaporising injection. The liners are then placed into the injection port to catalyse the gas phase reaction of volatile polar mixtures. Hydrogen gas is used both as the reactant for hydrogenation/hydrogenolysis, and as the carrier gas for the subsequent separation. The reaction products are mostly hydrocarbons, and are swept on to the column where they are chromatographically resolved by the non-polar stationary phase. The products are then identified by mass spectrometry. The fully active catalyst is effective in hydrogenating and isomerising alkenes as well as partially hydrogenating aromatic moieties. Desulphurisation of thiols, sulphides, and thiophenes readily occurs also. Oxygenated compounds such as primary alcohols, acids, esters and ethers undergo a decarbonylation/decarboxylation, while secondary alcohols are reduced to the parent hydrocarbon. Polar fractions react to produce compound distributions that are characteristic of the organic matter source, namely angiosperm-derived triterpenoids and bacterially-derived hopanoids. The reaction of the polar fraction from the Monterey Formation shale results in the formation of high relative amounts of pristane and phytane. A suite of steroids and triterpenoids, typical of marine organic matter, is also observed. R-GCMS provides less detailed information on the exact nature of the functionalised lipids partitioned within the polar fraction compared to more conventional wet chemical analyses. However, this technique requires only a GCMS instrument fitted with a vaporising injector, which acts as a chemical reactor at the inlet of the column. The main advantages of R-GCMS are its speed, low sample requirement, and production of easily resolved and identified products.
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nonGeographicDataset
eCat Id
38353
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
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2601
Australia
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- External PublicationAbstract
- ( Theme )
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- organic geochemistry
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2002-01-01T00:00:00
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