Pyrolysis spectrometry

Laser desorption is commonly used for pyrolysis/mass spectrometry, in which small samples are heated very rapidly to high temperatures to vaporize them before they are ionized. In this application of lasers, very small samples are used, and the intention is not simply to vaporize intact molecules but also to cause characteristic degradation. 

Py/GC/MS. pyrolysis, gas chromatography, and mass spectrometry used as a combined technique Py/MS. pyrolysis and mass spectrometry used as a combined technique oa-TOF. orthogonally accelerated time of flight Q. quadrupole field or instrument... 

Journal of Analysis and Applied Pyrolysis Journal of Chromatographic Science Journal of Chromatography Journal of Environmental Monitoring Journal of Liquid Chromatography Journal of Mass Spectrometry... 

Mass spectrometry has been used to determine the amount of H2 in complex gas mixtures (247), including those resulting from hydrocarbon pyrolysis (68). Mass spectrometry can also be used to measure hydrogen as water from hydrocarbon combustion (224,248). Moreover, this technique is also excellent for determining the deuterium hydrogen ratio in a sample (249,250). 

Pyrolysis mass spectrometry, which does not require a volatile derivative, has been applied to various penicillins (78MI51100). These spectra contained fragments arising from the bicyclic ring system (4,5-dihydro-5,5-dimethylthiazole at mje 115, 1- and 2-methylpyrrole at mje 81 and unidentified peaks at m/e 100 and 125) as well as a series of fragments characteristic of the C(6) side chain. 

The combination of the flash vacuum pyrolysis (FVP) technique169 with mass spectrometry proved to be particularly useful in identification and characterization of both the fragmentation/rearrangement patterns, intermediates and/or final products formed (see Section IV.E.l). Usually, no structures are indicated in the mass spectra, although ionization and appearance potential can, in principle, provide structural information. 

The carbon number distribution of technical secondary alkanesulfonates determined by pyrolysis gas chromatography and mass spectrometry (GC-MS) is shown in Fig. 13 together with the corresponding carbon number pattern of the raw material paraffins obtained by GC [16]. Pyrolysis was performed in a crucible-modified SGE pyrojector after covering the mixture with quartz wool. The presence of up to 10 wt % of disulfonates in technical alkanesulfonates is demonstrated by fast atom bombardment and mass spectrometry (FAB-MS) (Fig. 14) [24],... 

FIG. 13 Carbon number distribution of alkanemonosulfonates by pyrolysis gas chromatography (GC)/mass spectrometry (paraffin raw material by GC). 

The application of a selective pyrolysis process to the recovery of chemicals from waste PU foam is described. The reaction conditions are controlled so that target products can be collected directly from the waste stream in high yields. Molecular beam mass spectrometry is used in small-scale experiments to analyse the reaction products in real time, enabling the effects of process parameters such as temperature, catalysts and co-reagents to be quickly screened. Fixed bed and fluidised bed reactors are used to provide products for conventional chemical analysis to determine material balances and to test the concept under larger scale conditions. Results are presented for the recycling of PU foams from vehicle seats and refrigerators. 12 refs. 

Starting from 27, cyclo-Cig was prepared in the gas phase by laser flash heating and the neutral product, formed by stepwise elimination of three anthracene molecules in retro-Diels-Alder reactions, was detected by resonant two-photon-ionization time-of-flight mass spectrometry [23]. However, all attempts to prepare macroscopic quantities of the cyclocarbon by flash vacuum pyrolysis using solvent-assisted sublimation [50] only afforded anthracene and polymeric material. 

Perfluoroallyl radical, C3F5, was obtained by vacuum pyrolysis (850-950°C, 10 Torr) of 1,5-perfluorohexadiene or of 3-iodopentafluoro-propylene (14) and was studied by pyrolytic mass spectrometry (Kagrama-nov et al., 1983b) and by IR spectroscopy in an argon matrix (Mal tsev et al., 1986). 

R. Goodacre, D.B. Kell and G. Bianchi, Rapid identification of species using pyrolysis mass spectrometry and artificial neural networks of propionibacterium acnes isolated from dogs. J. Appl. Bacteriol., 76 (1994) 124-134. 

R. Goodacre, J. Pygall and D.B. Kell, Plant seed classification using pyrolysis mass spectrometry with unsupervised learning the application of auto-associative and Kohonen artificial neural networks. Chemom. Intell. Lab. Syst., 33 (1996) 69-83. 

Radovic, B. S., Goodacre, R., and Anklam, E. (2001b). Contribution of p)uolysis-mass spectrometry (Py-MS) to authenticity testing of honey. /. Anal. Pyrolysis. 60, 79-87. 

R. Goodacre, Characterisation and quantification of microbial systems using pyrolysis mass spectrometry introducing neural networks to analytical pyrolysis, Microbiol. (Europe), 2 19 (1994). 

Mie Scattering Particle Sizing -Pyrolysis-Gas Chromatography-Ion Mobility Spectrometry (FemtoScan, ECBC)... 

Figure 6.17 Temperature-resolved in-source pyrolysis FTICR-MS of flame-retarded polystyrene (56 spectra with a sampling interval of 1.1 s) from 300 K to 1200K. After Heeren and Boon [224], Reprinted from International Journal of Mass Spectrometry and Ion Processes, 157/158, R.M.A. Heeren and J.J. Boon, 391-403, Copyright (1996), with permission from Elsevier...

Various methods of analysis exert different thermal stress on a material (Table 6.39). Direct heating in the inlet of a mass spectrometer in order to obtain a mass spectrum of the total pyrolysate is an example of thermochemical analysis. Mass spectrometry has been used quite extensively as a means of obtaining accurate information regarding breakdown products produced upon pyrolysis of polymers. Low residence times allow detection of high masses. 

T-MS). The main direct mass-spectral methods are thermal desorption and pyrolysis mass spectrometry. Several factors favour the efficiency at which volatiles can be removed from a polymeric matrix ... 

Thermolysis-mass spectrometry is ideal for examining the amount of residual monomer and processing solvents present in polymers. In thermolysis, the polymer is heated from room temperature to 200-300 °C, and is then often held isothermally in order to drive off volatile components. Low-temperature pyrolysis (350-400 °C) of PP compounds in direct mass-spectral analysis has shown volatiles from PP at every carbon number to masses well above 1000 Da [37]. 

Apart from the aforementioned sample preparation techniques (SFE, SPE and SPME), other sample collection modes are coupled directly to spectroscopy (e.g. fast pyrolysis and fast thermolysis-FTIR) and spectrometry (e.g. LD-ITMS). 

PyMS Pyrolysis mass spectrometry SALS Small-angle light scattering... 

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