Abbreviations used amu Atomic mass units
CI Chemical ionisation
CID Collision-induced dissociation
EI Electron impact ionisation
Egi Energy of ionising electrons
FD Field desorption
FI Field ionisation
GC/MS Gas chromatography in tandem with mass spectrometry
HRMS High resolution mass spectrometry
MS Mass spectrometry
MS/MS Mass spectrometry in tandem with mass spectrometry
MW Molecular weight m/z The mass of the ion divided by its charge (usually unity)
Py-GC Pyrolysis-gas chromatography
Py-MS Pyrolysis-mass spectrometry
Py-TRMS Time-resolved pyrolysis-mass spectrometry
Tc Curie-point temperature
Teq Equilibrium temperature t Total heating time t-j- Temperature rise time
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In recent years pyrolysis mass spectrometry (Py-MS) has played an increasingly important role in analytical pyrolysis, which is traditionally dominated by pyrolysis gas chromatographic methods. This tendency first became evident during the Illrd International Symposium on Analytical Pyrolysis held in July 1976 in Amsterdam, and has continued to manifest itself during the 1978 conferences in Budapest (IVth International Symposium on Applied and Analytical Pyrolysis) and Plymouth, New Hampshire (Gordon Conference on Analytical Pyrolysis), and also at international mass spectrometry conferences and in the recently established Journal of Analytical and Applied Pyrolysis.
Whereas specially designed Py-MS systems using galvanically heated filament or direct probe pyrolysers have been quite successful in structural investigations and kinetic studies involving synthetic polymers and model compounds, Curie-point Py-MS systems have proved to be uniquely advantageous in applications that require maximum reproducibility in fingerprinting and also in applications that require routine analysis of hundreds or thousands of samples. This has made the Curie-point approach especially valuable for extremely complex samples, such as are encountered among materials of biological origin, ranging from biopolymers, cells, microorganisms and tissues to humic substances, sediments, peats, coals and shales.
Probably the most extensively used Py-MS system is the fully automated Curie-point Py-MS system at the F.O.M. Institute for Atomic and Molecular Physics in Amsterdam. From January 1977 to January 1980 this system produced about 18,000 pyrolysis mass spectra for over 100 different users. One visitor to this facility, Dr. F. W. McLafferty, described his impressions as follows: "For biopolymers and other high molecular weight substances, automated pyrolysis-MS, developed by H.L.C. Meuzelaar, P. G. Kistemaker, W. Eshuis, M. A. Posthumus and A. J. U. Boerboom of the FOM Institute in Amsterdam, is now an impressive routine analytical tool running literally thousands of samples per year, such as geo- and synthetic polymers, coal, sewage, and urine without sample workup. The capability to characterise bacteria is particularly impressive and could revolutionize the classical methods which have been used by clinical laboratories since Pasteur."
In the course of their own involvement with the Py-MS facility at the F.O.M. Institute, the authors* have sensed an increasing need for a compendium describing the
* H.L.C. Meuzelaar was founder and Director of the F.O.M. Pyrolysis Centre from 1970 to 1978; J. Haverkamp is the present Director of the F.O.M. Pyrolysis Centre; and F. Hileman was a guest scientist at the Centre in 1978.
basic principles, techniques and applications of Curie-point Py-MS aimed at past, present and future users of the method. The authors further felt that this compendium should focus on recent and fossil biomaterials rather than on synthetic compounds because of the above-mentioned unique advantages of Curie-point Py-MS for the analysis of extremely complex samples.
The need for a compendium became even more urgent with the'advent of commercially available Curie-point Py-MS systems from at least two different manufacturers* in 1979. This prompted the authors to include a small Atlas of reference spectra of carefully selected biomaterials which should help new users of Curie-point Py-MS systems to "tune" their instruments to the existing systems and to evaluate unknown spectra.
A few compounds of non-biological origin, e.g. synthetic polymers, are included in the Atlas to demonstrate the applicability of the technique to these classes of compounds and to provide some relatively simple spectra for "tuning" purposes. Moreover, synthetic compounds are often encountered as constituents or contaminants in biomaterials offered for analysis.
In order to avoid confusions and disappointment it should be stressed that the Atlas part of this book will primarily assist in the qualitative interpretation of pyrolysis mass spectra. In general, the peak assignments given are tentative and have not yet been confirmed by high resolution MS or US/MS. Although a definite level of interlaboratory reproducibility can be shown to exist between Curie-point Py-MS systems of the same basic design, as discussed in Chapter 5, the establishment of a library for quantitative comparison between spectra from different instruments, e.g. for fine differentiation between bacterial patterns, is still beyond the present state of the art.
Although many applications of this technique deal with the classification and identification of microorganisms, fungi and cells, model spectra of such materials have not been included in the Atlas as their "fingerprints" depend strongly on experimental conditions such as cultivation and preparation methods.
Finally, an important category of readers to whom this Compendium and Atlas should prove helpful are those considering the application of Py-MS techniques to their own specific problems in the analysis of biomaterials of widely different types. The authors hope that the broad range of applications and spectra presented will enable a fair assessment of the present capabilities and limitations of Curie-point Py-MS in the analysis of complex biomaterials, with regard both to known applications and to more or less closely related new applications not specifically covered in this text.
* Extranuclear Laboratories Inc., Pittsburgh, U.S.A., and V.G. Micromass Ltd., Winsford, U.K.
The authors gratefully acknowledge the gift of samples by the National Bureau of Standards (Wash ington, U.S.A.), Drs. E. C. Beuvery (Rijksinstituut voor de Volks-gezondheid (R.I.V.), Bilthoven, The Netherlands; polysaccharide antigens), Dr. J. Borst (R.I.V., Bilthoven, The Netherlands; Neisseria gonnorrhoea strains), Dr. H.W.B. Engel (R.I.V., Bilthoven, The Netherlands; Mycobacterium strains), Dr. H.M. Greven (Organon, Oss, The Netherlands; synthetic oligopeptides), Dr. K. Haider and Dr. C. Saiz-Jimenez (Forschungsanstalt "fur Landwirtschaft, Braunschweig, W. Germany; humic materials), Dr. S.M. Kunen (University of Utah, U.S.A.; air particulates) Dr. S. R. Larter (Union Oil Company, U.S.A.; kerogens), Dr. J. W. de Leeuw and Prof. P.A. Schenck (Technical University of Delft, The Netherlands; oil shales, coals and lignite), Dr. T. Meindersma (Academisch Ziekenhuis Dijkzigt, Rotterdam, The Netherlands; Klebsiella strains), Dr. J. H. Petajan (University of Utah, U.S.A.; muscle samples), Dr. G. Schutgens (Binnengasthuis, Amsterdam, The Netherlands; urine samples), Dr. G. Sposito (University of California, Riverside, U.S.A.; sludge samples) and Ir. A. L. van Wezel (R.I.V., Bilthoven, The Netherlands; poliomyelitis virus preparations).
Further, the authors are indebted for unpublished data to Dr. P. G. Kistemaker (F.O.M. Institute for Atomic and Molecular Physics, Amsterdam, The Netherlands; laser Py-MS of DNA), Dr. M. A. Posthumus (Agricultural University, Wageningen, The Netherlands; Py-MS of nucleic acids), Dr. H. -R. Schulten (University of Bonn, W. Germany; scheme of pyrolytic degradation of glycogen), and Dr. W. Windig (F.O.M. Institute; factor analysis with rotation). Finally, the authors thank Ms. A. Tom and Ms. B. Brandt (F.O.M. Institute for Atomic and Molecular Physics, Amsterdam) for preparing most of the analyses, Dr. W. Eshuis for computer analysis of the data, Dr. P. G. Kistemaker, Dr. M. A. Posthumus and Dr. J. W. de Leeuw for critical reading of the manuscript and Mrs. M. Van for typing and editing the manuscript. The research reported in this book was supported by the Foundation for Fundamental Research on Matter (F.O.M.) and the Ministry of Health and Environmental Hygiene in The Netherlands, and by the United States Department of Energy.
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