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Charred organic remains are ubiquitous in the archaeological and fossil record and are often used to interpret past environments and climate. This study focuses on the physical and chemical alteration that takes place during heating (i.e. charring). Modifications to the internal and external morphology were noted alongside the change in molecular and stable carbon isotope signature. Molecular analyses were undertaken using direct temperature resolved mass spectrometry and the stable carbon isotopes determined using isotope ratio mass spectrometry. The results of this study document a general enrichment in 13 C/ 12 C composition of charred material which could reflect the changes observed in both the molecular composition and the relative proportions of the molecules formed. These results indicate that spurious results might be inferred when comparing the stable carbon isotope signature of charred/charcoalified material with uncharred organic matter

The remarkable physical and chemical resistance of the organic cell walls enclosing resting cysts formed by several species of dinoflagellates has long invited questions regarding their composition. Traditionally, this resistance was thought to derive from the presence of “sporopollenin”, a term originally coined to describe the highly refractory substance found in the walls of pollen and spores of higher plants. The lack of detailed chemical analyses of dinoflagellate materials, however, has left this practice open to question. Here we report the results of the first rigorous chemical characterization of resting cyst walls produced by a dinoflagellate, the extant marine species Lingulodinium polyedrum (formerly Gonyaulax polyedra). Resistant cell walls were isolated by sequentially treating cyst-producing laboratory cultures by solvent extraction, saponification, and acid hydrolysis. At each stage of processing, residues were characterized by light microscopy, FTIR microspectroscopy, elemental analysis, and direct (“in source”) temperature–resolved mass spectrometry (DT–MS). Initial materials and final residues were further analyzed by Curie-point pyrolysis–gas chromatography–mass spectrometry (Py–GC/MS) and cupric oxide (CuO) oxidation. Overall, our results indicate an absence of extended n-hydrocarbon chains which typify aliphatic macromolecules (“algaenans”) dominating the resistant fractions of other algae studied to date. In contrast the data suggest that the cell wall contains relatively condensed, predominantly aromatic structures, possibly cross-linked via carbon–carbon or ether bonds. The presence of prist-1-ene among the most prominent pyrolysis products also suggests that bound tocopherols function as additional structural elements in the wall material(s). The L. polyedrum resting cyst cell wall thus appears to contain a biomacromolecular substance that is distinct from both sporopollenin and aliphatic algaenans. These findings help to further establish a chemical basis for the preservation potential of organic biomacromolecules, and illuminate possible chemical/functional relationships among highly refractory substances from diverse biological sources.

In this study the morphological and chemical heterogeneity of particulate organic matter (POM) in the surface ocean was investigated by the application of flow cytometry, direct temperature-resolved mass spectrometry (DT-MS), and multivariate statistics. In order to obtain a diverse collection of surface-ocean POM samples, POM was collected from a station in Great Harbor, Woods Hole, MA, U.S.A. (on a monthly basis) and on transects across the Mid-Atlantic Bight (in March 1996). Small-particle ( μ m) POM was separated from large-particle (>53 μ m) POM by filtration through a nylon screen. Aliquots of the small-particle POM were then further separated, via flow cytometric sorting, into phytoplankton and detrital pools. Broad-band molecular-level characteristics of these POM subclasses were obtained through DT-MS (16 eV, EI + ) and were explored via principal component and discriminant analyses. For both the Woods Hole (WHTS) and the Mid-Atlantic Bight (MAB) data sets, the statistical treatments separated POM samples primarily according to their class and subclass distinctions; therefore, this paper focuses on the molecular-level differences among large-particle and small-particle POM, phytoplankton and detritus. Small-particle POM is found to be more enriched in protein, phytosterols, diglycerides and chlorophyll than large-particle POM, which is more enriched in pentose polysaccharide fragments, C 16:0 fatty acid, and cholesterol. At the WHTS site, large-particle POM is also enriched in chitin and appears to contain a significant grazer biomass component. In the MAB, the corresponding POM fraction appears more phytodetrital. Phytoplankton particles are enriched in protein, chlorophyll and lipids relative to detritus. Detritus is enriched in selected polysaccharides and appears to be composed of phytodetritus and/or fecal material.

Marine colloidal organic matter in coastal waters off the coast of the eastern United States (from Georges Bank and the Mid-Atlantic Bight) is characterized by means of direct temperature-resolved mass spectrometry (DT-MS). Chemical ionization (NH 3 ) appears to be a very appropriate ionization method for this material. The analytical data confirm the presence of a significant polysaccharide fraction consisting of neutral sugars (normal-, deoxy- and methylated aldoses), N -acetyl aminosugars and, possibly, acidic sugars. The methylated and N -acetyl aminosugars are considered as markers for a bacterial contribution. No evidence is found for polysaccharides with large homopolymeric domains, suggesting an origin distinct from the common structural polysaccharides that comprise major polymers in algae and higher plants. The TIC profiles, which express the number of ions produced as a function of the temperature, often show a bimodal distribution. This indicates that the colloidal matter consists of two fractions with different thermal stabilities and probably also different chemical stabilities. Multivariate “mapping” of the DT-MS spectra reveals that the chemical differences between these two fractions show remarkable conformity amongst samples collected at widespread locations. The relative abundance of the two fractions appears to depend on both depth and location. The more thermally stable fraction is relatively abundant in deep water samples and some surface waters of the Mid-Atlantic Bight.

In order to determine terrestrial contributions to the organic matter pool in the marine environment, a reliable chemical tracer is required. Lignin, an abundant component of vascular plant tissue is often used as such. In this study the lignin moiety of both fresh and degraded tissue of the model halophyte Spartina anglica was purified and chemically characterized to investigate its suitability as tracer. The study can be split into three parts. In the first part several enzymatic lignin purifications of fresh S. anglica tissue were compared with each other. In the second part pyrolysis gas chromatography mass spectrometry was applied to analyse untreated and on-line methylated milled wood lignin preparations. The previous characterizations of the lignin moiety of S. anglica were used in the third part to monitor modifications in the chemical composition induced by natural aerobic decomposition in the field. The temperature at which lipids were extracted from the original tissue was not critical, although low temperatures improved the purification to some extent. For enzymatic purification of lignin the use of a polysaccharidase turned out to be the most important prerequisite. The use of a protease did not have much influence on the lignin residue. After 2 yr of aerobic decomposition, the lignin character of untreated S. anglica tissue was no longer identifiable with direct temperature-resolved mass spectrometry, but it still could be retrieved in the residue obtained after enzyme treatment. With continuing decomposition the chemical structure of the lignin moieties became partly modified. The very complicated spectra obtained after longer decomposition periods suggest the formation of a heterogeneous organic fraction, probably representing "humic substances". The gradual loss of lignin characteristics in the litter makes its suitability as tracer for terrestrial material in a complex mixture of substances doubtful, at least with the analytical technique applied in this study. [KEYWORDS: lignin; Spartina anglica; halophyte; litterbag decomposition; pyrolosis; mass spectrometry; TMAH Salt-marsh sediments; discriminant-analysis; organic-matter; early diagenesis; flash pyrolysis; alterniflora;biodegradation; lignocellulose; polymers; wood]

Siegburgite, an unusual Tertiary aromatic resin found near Bitterfeld (Germany), has been characterised earlier by FTIR spectrometry as polystyrene-like material. Here the molecular weight distribution of the soluble part is determined by size-exclusion chromatography (SEC) to be bomodal with maxima at 400 and 30,000 Da. Using combined gas chromatographic-mass spectrometric techniques (GC–MS) traces of oleanonic and 3-epi-oleanolic acid are found in the low MW fraction of Siegburgite. 3-Phenylpropanylcinnamate is detected in the high MW fraction by pyrolysis (Py)–GC–MS. Although also present in the soluble part of the high MW fraction, this compound is present especially in the insoluble residue, indicating that the ester is incorporated in the polymer chain. Oleanonic acid, 3-epi-oleanolic acid and 3-phenylpropanylcinnamate are constituents of commercially available Gum Storax from modern Liquidambar orientalis Mills. The proposed paleobotanical origin of Siegburgite from the Hammamelidacae family is thus chemically confirmed. In addition, a comparable polystyrene-like resin originating from North America (Squankum New Jersey) was compared to Siegburgite. The polystyrene matrix of this resin is comparable to that of Siegburgite, but no molecular markers confirming its origin could be found.

The geochemical and petrographic character of the matrix of the Oligocene, angiospermous Brandon lignite, Vermont, is examined and compared to samples of a common fossilized angiosperm wood and fruit endocarp contained within the lignite. The lignite matrix is composed primarily of humodetrinite and liptodetrinite while the megafossils are overwhelmingly humotelinitic (textinite and ulminite). Curie-point Py-MS, in-source Py-EI-MS, in-source Py-CI-MS, and CPMAS 13C NMR reveal that the polymers comprising the matrix include a highly aliphatic polymer(s) and polymer(s) derived from the significantly modified remains of angiosperm lignin(s). Very few polysaccharides are preserved in the matrix. The polymer(s) in each megafossil contain(s) significant proportions of polysaccharides and lignins which are, however, significantly altered from their Recent equivalents. The results suggest that anatomical preservation and physical integrity of discrete megafossils within peats and lignites are directly related to the degree to which the original ligno-cellulosic framework is preserved. This implies that the humotelinitic macerals comprising the megafossils contain ligno-cellulose-derived polymers that are less modified than those comprising the humodetrinite within the matrix. The liptodetrinite within the matrix is probably comprised of highly aliphatic polymers derived from cutans and/or alginans. Upon further coalification the vitrinite within the vitrain bands derived from the megafossils and vitrinite within the clarain bands derived from the matrix would be distinct.

Infrared and CP-MAS 13 C-NMR Spectroscopy, Py-GC-MS and Py-MS techniques have been applied to samples of the five main lithotypes occurring in the Latrobe Valley brown coal deposits in Victoria, Australia. The analyses are compared with data from samples of fossilized and gelified wood from the coal deposit. The lithotypes fall into two groupings, viz. Dark (D), Medium Dark (MD) and Pale (P), Light (L), Medium Light (ML) on the basis if depositional inputs. The Dark lithotype is more closely related to gelified wood whilst the Medium Dark lithotype relates to fossilized wood. The three lighter lithotypes show similarities one to another but are not strongly related to wood precursors.

Melanoidins of glucose or galactose and the amino acids tyrosine, methionine and lysine were analysed by Curie point pyrolysis-mass spectrometry and pyrolysis-gas chromatography-mass spectrometry. Specific chain characteristics of the reactant amino acids were visible in the pyrolysis data, whereas pyrolysis products of carbohydrates related structural elements in the melanoidins were found to be more sensitive to the nature of the amino acids and the sugar amino acid ratio. The influence of the pyrolysis temperature was tested on galactose-lysine melanoidins by comparison of pyrolysis-mass spectra obtained at 510, 610 and 770°C using multivariate data analysis techniques. The effect of the end temperature on the spectra of this melanoidin was found to be small.

Suspended matter from surface microlayers and various water depths, plankton and surface sediments have been collected at various Mediterranean sites and have been subjected to flash pyrolysis techniques to study the scope of pyrolysis methods in the analysis of the chemical composition of suspended organic matter in the ocean. Samples have been analysed by both pyrolysis-mass spectrometry (Py-MS) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). Discriminant analysis of the Py-MS spectra of 26 samples indicated the amplitude and nature of the variance between the samples. By means of Py-MS fingerprints, the samples are separated into well-defined clusters, reflecting the nature, the geographic origin and the sampling depth. The differences observed are due to varying amounts of peptides, polysaccharides and lipids. The plankton samples are clearly separated due to their high content in recently biosynthesized material, such as proteins. Other samples collected in coastal areas, especially in the Northern Adriatic Sea, are characterized by relatively high contents of polysaccharides probably due to high riverine nutrient inputs and consequently a high plankton productivity. The chemical interpretations of the Py-MS data are based on Py-GC-MS data of a few selected samples. Py-GC-MS traces allow the detailed identification of pyrolysis products derived from peptides, polysaccharides, lipids, lignin and others. Flash pyrolysis techniques appear to be a useful tool to study the chemical nature of suspended matter, allowing the determination of major building blocks of complex mixtures of biopolymers, degraded biopolymers and condensation products, present in the suspended matter of the ocean.