Analytical pyrolysis ionization mass spectrometry

Analytical pyrolysis with field ionization mass spectrometry (online Py-FIMS) or in combination with GC/MS (Curie point Py-GC/MS) led to a significant increased number of identified subunits (e.g., Bracewell et al., 1989 Schulten et al., 2002). In addition, the application of tetramethylammonium hydroxide (TMAH) methylation, followed by GC/MS, was successfully applied. The most abundant pyrolysis products identified are benzene, phenol and furan derivatives, aliphatic and carboxylic compounds, and indene derivatives (Schulten et al.,2002). New approaches have been used for the quantification of n-alkyl fatty acids of DOM and isolated fractions in the form of individual compounds after solvent extraction followed by derivatiza-tion with TMAH. 

ANALYTICAL PYROLYSIS AND SOFT-IONIZATION MASS SPECTROMETRY... 

Analytical pyrolysis is defined as the characterization of a material or a chemical process by the instrumental analysis of its pyrolysis products (Ericsson and Lattimer, 1989). The most important analytical pyrolysis methods widely applied to environmental samples are Curie-point (flash) pyrolysis combined with electron impact (El) ionization gas chromatography/mass spectrometry (Cp Py-GC/MS) and pyrolysis-field ionization mass spectrometry (Py-FIMS). In contrast to the fragmenting El ionization, soft ionization methods, such as field ionization (FI) and field desorption (FD) each in combination with MS, result in the formation of molecule ions either without, or with only very low, fragmentation (Lehmann and Schulten, 1976 Schulten, 1987 Schulten and Leinweber, 1996 Schulten et al., 1998). The molecule ions are potentially similar to the original sample, which makes these methods particularly suitable to the investigation of complex environmental samples of unknown composition. 

Schulten H.-R. (1987) Pyrolysis and soft ionization mass spectrometry of aquatic/terrestrial humic substances and soils. J. Analyt. Appl. Pyrol. 12, 149—186. 

Numerous studies have been performed on polyethylene pyrolysis [22-41]. These studies include flash pyrolysis in He, in air, in the presence of various catalysts, in the presence of steam, under pressure, etc. Also, besides analytical pyrolysis, some of the studies were performed at slow heating rates that better simulate pyrolysis in industrial incinerators. Most frequently, the analysis of polyethylene pyrolysates has been done using GC/MS. However, other techniques also were applied, such as pyrolysis field ionization mass spectrometry [42]. 

Figure 5 Schematic drawing of the experimental setup for pyrolysis field ionization mass spectrometry. Reproduced by permission of the American Chemical Society from Schulten H-R, Simmleit N and Muller R (1987). Analytical Chemistry 6S 2903-2908.

A variety of volatilization/ionization methods have been applied to polymers a recent review or key paper is cited here for each. Extensive reviews that include mass spectrometry of pol5mrers can be found in Analytical Chemistry Other to )ical reviews are field desorption, laser desorption, plasma desorption, fast-atom bombardment, pyrolysis, and electrospray ionization. The present review will focus on polymer characterization using secondary-ion mass spectrometry (SIMS) in the high mass range comparison with other methods will be presented where appropriate. 

Barshick SA, Wolf DA, and Vass AA (1999) Differentiation of microorganisms based on pyrolysis ion trap mass spectrometry using chemical ionization. Analytical Chemistry 71 633-641. 

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