regarding the extent of applicability. ACKNOWLEDGMENTThe authors express their gratitude to D. R. Ells for his invaluable assistance with the apparatus, to N. E. Ballou for his help with the manuscript, and to J. A. Holcombe for valuable suggestions concerning this work.BeO, 1304-56-9; Mg, 7439-95-4; graphite, Registry No.7782-42-5. LITERATURE CITED(1) Maessen, F. J. M. J.; Balke, J.; Massee, R.An Improved experknental setup for tlmaresolved In-source pyrolysls (Py) field lonlzatlon ( F I ) mass spectrometry (MS)

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Abstract. Spruce needles of different age, litter materials and soil samples from the L-, Oand A-horizons of a mor profile were analysed by temperature-programmed pyrolysis (Py) in combination with field ionization mass spectrometry (FIMS). The integrated Py-n mass spectra give characteristic fingerprints of the biomaterials investigated. The application of principal component analysis to the mass spectral data results in a clear discrimination and classification of the samples reflecting the chemical modifications and transformations of organic matter by biochemical and biogeochemical processes. The chemical compositions are determined by processes such as enrichment and/or translocation of plant constituents (e.g. carbohydrates, lignin, lipids, suberin, and aliphatic poiymers) during maturation and senescence of needles; amendment of new components; decomposition; selective preservation and humification processes in the soil environment.During needle maturation, major chemical changes include the decrease of carbohydrate content, condensation of lignin, and crosslinking of wazes. Senescent needles are characterized by lower contents of carbohydrates and lower yields of monomeric pyrolysis products from lignin. The contribution of different litter materials to the humus layer can be estimated by differences in chemical composition. During litter decomposition and humification on the forest floor, carbohydrate content decreases rapidly. The lignin content remains almost constant but some subunits are continuously oxidized. Wax material accumulates until the me&r&al disintegration of the needle occurs. In the O-horizons polymeric aliphatic materials are enriched in humified plant remains. A constant increase of aryl-alkyl esters from suberin in the O-horizons is due to both root input and selective preservation. In general, mainly aliphatic polymers and aryl-alkyl esters accumulate during the genesis of mor profiles under conifers.

Three different vacuum pyrolysis mass spectrometry techniques, viz., pyrolysis-field ionization mass spectrometry, thermogravimetry/low voltage electron ionization mass spectrometry, and Curie-point pyrolysis-low voltage electron ionization mass spectrometry, were used to analyze samples of Pittsburgh No. 8 coal obtained from the Argonne National Laboratory Premium Coal Sample Program. The primary objective was to assess the effects of differences in experimental techniques and conditions, e.g., with regard to heating rates, pyrolysis methods, and soft ionization procedures (FI vs low voltage EI) on the mass spectral patterns. A second objective was to further characterize and study the pyrolysis behavior of Pittsburgh No. 8 coal. The results indicate that the distribution and the type of the primary pyrolysis products are largely independent of marked differences in heating rate (10-2-104 K/s range) and sample size (2.5 X g range) as well as overall vacuum pyrolysis MS configurations and conditions used. All three vacuum pyrolysis MS techniques produce remarkably similar mass spectral patterns when analyzing Pittsburgh No. 8 coal. The results show that Pittsburgh No. 8 coal contains a significant amount of low temperature (<380 " C ) evolving "bitumen" consisting primarily of alkyl-substituted aromatic components. The bitumen evolution step is followed by partially overlapping "bulk pyrolysis" step characterized by the evolution of abundant hydroxy-and dihydroxy-substituted aromatic compounds, thought to be primarily derived from vitrinitic components. During the bitumen evolution step the average MW of the compounds increases with temperature while maintaining a relatively narrow distribution. By contrast, during the bulk pyrolysis step, the average MW tends to decrease while exhibiting a much broader distribution.to 5.0 X