Pyrolysis analysis

Concentration techniques in GC are used mainly for trace analysis. Pyrolysis commonly generates enough material for a GC analysis even when a very small amount of sample is taken for analysis. For this reason, concentration techniques are not frequently associated with Py-GC. However, in some instances it is necessary to analyze both the volatile compounds that are generated at mild heating of the polymer (sometimes below 100° C) and also the typical pyrolysis products. Several two-step (or multi-step) experiments were reported [40c] that allow this type of analysis. 

Figure 6.6.2. Result fora off-line pyrolysis of a poly(4-vinylphenol) M = 8000 followed by silylation and GC/MS analysis. Pyrolysis done at BOCP C in He, with the separation on a 5% phenyl methylsilicone column.

Ultraviolet (UV) and visible light absorption 0.2 < X(p.m) < 0.8 Functional group analysis Pyrolysis/ozonolysis... 

A suitable method for monitoring remaining impurities is gel permeation chromatography. The chemical structure of the macromolecule can then be elucidated by the usual methods (nuclear magnetic resonance, infrared and ultraviolet spectroscopy, elemental analysis, pyrolysis coupled with gas chromatography, etc.). 

In combination with IR analysis, pyrolysis GC is particularly useful in the following areas ... 

Thermal volatilization analysis (pyrolysis analysis, TVA) n. Ramp heating of a plastic with passage of the evolved volatiles through one or more chemical detectors, sometimes with intervening, controlled-temperature, vapor-condensing traps. TVA is a powerful technique when coupled with thermogravimetric analysis. 

When solid samples (such as soil, rock, or ice) are to be analyzed with MS, sample extraction techniques play a crucial role in both introducing the samples into the mass spectrometer and the subsequent analysis. Pyrolysis is... 

Apparatus and experimental techniques have been discussed in several papers. The techniques include thermal volatilization analysis," pyrolysis-gas chromatography, pyrolysis-molecular weight chromatography-i.r. spectrophotometry, and pyrolysis-mass spectrometry. Methods have also been described for collecting and separating pyrolysis products. - ... 

Some operational PyGC-MS variants are available (i) thermally assisted alkylation (ii) oxidative pyrolysis and (in) temperature-resolved PyGC-MS (cfr. Chp. 2.2.7). In situ thermally assisted methyla-tion GC-MS with tetramethylammonium hydroxyde (TMAH) (Py-TMAH-GC-MS) has been reported as a useful analysis technique for analysis of polar analytes [636]. In case of normal PyGC analysis, pyrolysis is performed in inert gas (N2, He or H2) as a carrier gas. Oguri et at. [584] have recently described a combustion gas analyser composed of a... 

As an alternative to wet ehemical routes of analysis, this monograph deals mainly with the direct deformulation of solid polymer/additive compounds. In Chapter 1 in-polymer spectroscopic analysis of additives by means of UV/VIS, FTIR, near-IR, Raman, fluorescence spectroseopy, high-resolution solid-state NMR, ESR, Mossbauer and dielectrie resonance spectroscopy is considered with a wide coverage of experimental data. Chapter 2 deals mainly with thermal extraction (as opposed to solvent extraction) of additives and volatiles from polymerie material by means of (hyphenated) thermal analysis, pyrolysis and thermal desorption techniques. Use and applieations of various laser-based techniques (ablation, spectroscopy, desorption/ionisation and pyrolysis) to polymer/additive analysis are described in Chapter 3 and are critically evaluated. Chapter 4 gives particular emphasis to the determination of additives on polymeric surfaces. The classical methods of... 

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

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