Headspace analysis pyrolysis

Special injection techniques are employed for headspace analysis, pyrolysis gas chromatography and thermal desorption to concentrate samples (Topic D5). 

See also Activation Analysis Neutron Activation. Atomic Absorption Spectrometry Principles and Instrumentation. Atomic Emission Spectrometry Principles and Instrumentation. Chromatography Overview Principles. Gas Chromatography Pyrolysis Mass Spectrometry. Headspace Analysis Static Purge and Trap. Infrared Spectroscopy Near-Infrared Industrial Applications. Liquid Chromatography Normal Phase Reversed Phase Size-Exclusion. Microscopy Techniques Scanning Electron Microscopy. Polymers Natural Rubber Synthetic. Process Analysis Chromatography. Sample Dissolution for Elemental Analysis Dry... 

Heat extraction techniques for solid sample preparation in GC are static and dynamic headspace analysis (SHS, DHS, HS-SPME and HSSE), thermal desorption (TD-GC, TD-GC-MS), pyrolysis and thermochromatography. Nomenclature is not unambiguous as to DHS, TD and PT. The terminology purge-and-trap is usually preferred for the simplest dynamic technique in which it is not necessary to subject the sample to either solvents or elevated temperatures. Scheme 2.7 shows the family of headspace sampling techniques. Headspace sorptive extraction (HSSE) and HS-SPME represent high capacity static headspace. 

Implementation The GC-MS of the sample headspace finds no perfume compounds. The cream is found to be greater than 80-wt% organic matter. Pyrolysis-GC-MS identified significant levels of glucose polymers, which were confirmed by FTIR to be either cellulose or starch. The iodine test revealed that the glucose polymer was starch. Further GC-MS analysis did not find cholesterol, but did find trace levels of a cholesterol degradation product. 

EXMAT - A Linked Network of Expert Systems for Materials Analysis. Seven individual expert systems comprise EXMAT (1) problem definition and analytical strategy (2) instrumental configuration and conditions (3) data generation (4) chemometric/search algorithms (5) results (6) interpretation (7) analytical goals. Dynamic headspace (DHS)/GC and pyrolysis GC (PGC)/concentrators... 

Inks and prints are analysed in order to ensure safety. This includes testing for harmful substances with potential to migrate into food. Environmental pressure may result in a demand for testing, for example, vegetable oils versus petroleum distillates. There might also be a need to determine the content of aromatic compounds in the ink in order to avoid odour and taint problems. For chemical analysis of prints and determination of ink components a number of methods are available, such as pyrolysis, infra-red spectrometry, gas chromatography and mass spectrometry. Volatile compounds are usually analysed by a headspace technique. The progress in chemical analysis is so rapid that any method may be considered obsolete after a limited number of... 

The first preliminary work in which vapor examination of headspace samples was used for the analysis of traces of accelerants was reported by Midkiff and Washington in 1972 (180). Since then many studies have been performed in regard to heating conditions, container size, sample size, the effect of water, the degree of interference from pyrolysis products, and the chromatographic conditions, including the type and dimension of column. 

Thermal evolution analysis is an excellent tool for polymer studies complementary to other thermal techniques such as DTA, TG and pyrolysis. Its applications include thermal degradation studies, determination of additives and contaminants, polymer composition and structure identifications. With small variations, the apparatus can also be used for vapour pressure measurements, and for determination of odorous materials in polymer systems. Coupling of TEA to GC for the identification of effluents is practicable and useful. TEA-CT-GC was used for the analysis of volatiles from ABS 10 ppb of styrene but negligible acrylonitrile was detected in the headspace of a typical ABS resin [42]. 

Chances for successful identification and quantification are considerably enhanced when analytes are separated. For solutions, chromatography is the supreme tool, whereas for solids some form of thermal treatment may achieve fractionation of matter according to volatility. Vapour evolution from polymers may be controlled and studied by various means, such as sublimation, thermal distillation, vacuum TG-MS, thermal evolution analysis (TEA) including TVA, headspace techniques or thermal desorption. It is obviously desirable that evaporation of the additives takes place below the decomposition temperature of the polymer. In principle, this can also be realised in thermal-programmed pyrolysis (dry distillation in vacuum). Desorption processes are controlled by diffusion. 

Mass spectrometry and chemometric methods cover very diverse fields Different origin of enzymes can be disclosed with LC-MS and multivariate analysis [45], Pyrolysis mass spectrometry and chemometrics have been applied for quality control of paints [46] and food analysis [47], Olive oils can be classified by analyzing volatile organic hydrocarbons (of benzene type) with headspace-mass spectrometry and CA as well as PC A [48], Differentiation and classification of wines can similarly be solved with headspace-mass spectrometry using unsupervised and supervised principal component analyses (SIMCA = soft independent modeling of class analogy) [49], Early prediction of wheat quality is possible using mass spectrometry and multivariate data analysis [50],... 

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