Lignin Decomposition Products Research Articles

Accelerated and Natural Aging of Cellulose-Based Paper: Py-GC/MS Method

Samples of papers artificially (2 to 60 days) and naturally (10, 45, and 56 years) aged were studied by the Py-GC/MS method to identify decomposition products. Possible reaction scenarios for cellulose degradation were developed. One of the degradation products is acetic acid, which can (auto)catalyze the cleavage of cellulose β(1→4)-glycosidic bonds of cellulose polymer chains. However, during 20 s of Py-GC/MS analysis, temperatures of up to 300 °C did not significantly increase or modify the formation of decomposition products of paper components. At 300 °C, the amount of several cellulose decomposition products increased regularly depending on the number of days of artificial aging and natural aging, demonstrated mainly by the generation of 2-furancarboxaldehyde, 5-hydroxymethylfurfural, and levoglucosan and its consecutive dehydration products. No correlation between the amount of lignin decomposition products and the time of aging was found when the pyrolysis was performed at 300 °C and 500 °C. Compounds present in the products of decomposition at 500 °C bear the imprint of the chemical composition of the sampled paper. Pyrograms taken at 300 °C using the Py-GC/MS method can give additional information on the changes in the chemical structure of paper during natural or artificial aging, mainly about the cleavage of β(1→4)-glycosidic bonds during aging.

Selection of bacteria capable of biodegradation of organic nitrogen-containing compounds and metagenomic analysis of their living environment

Samples of karst lakes, rivers, industrial effluents, and natural soil were studied for selection of bacteria for biodegradation. A metagenomic analysis of the used natural and man-modified media was carried out. It has been established that the most unique are the compositions of the metagenomes of natural karst reservoirs, as well as microcenoses of industrial effluents. Most of the detected bacteria belong to Proteobacteria. As a result of selection, strains of microorganisms with high activity of nitrocellulose biodegradation, aromatic nitrates, quinoline derivatives and amides were obtained. In particular, Pseudomonas strains and R. erythropolis, effectively utilizing nitrobenzenes, nitrocellulose, quinolines, which were isolated from industrial effluents. At the same time, Pseudomonas strains were isolated from the natural karst lake, which quickly utilized the nitrocellulose. It was also found that natural soils contain a large number of prokaryotes that can utilize organic nitrates. The results confirm the view that natural environments, due to high metabolic diversity, are the richest source of producers of a wide variety of enzymes. An obvious reason for the proliferation of the metabolic systems of technogenic pollutants in natural environments is the presence in natural environments of some quantities of their structural analogues - nitrogen-containing plant metabolites and soil microflora, as well as lignin decomposition products.

Enrichment of Lignin-Derived Carbon in Mineral-Associated Soil Organic Matter.

A modern paradigm of soil organic matter proposes that persistent carbon (C) derives primarily from microbial residues interacting with minerals, challenging older ideas that lignin moieties contribute to soil C because of inherent recalcitrance. We proposed that aspects of these old and new paradigms can be partially reconciled by considering interactions between lignin decomposition products and redox-sensitive iron (Fe) minerals. An Fe-rich tropical soil (with C4 litter and either 13C-labeled or unlabeled lignin) was pretreated with different durations of anaerobiosis (0-12 days) and incubated aerobically for 317 days. Only 5.7 ± 0.2% of lignin 13C was mineralized to CO2 versus 51.2 ± 0.4% of litter C. More added lignin-derived C (48.2 ± 0.9%) than bulk litter-derived C (30.6 ± 0.7%) was retained in mineral-associated organic matter (MAOM; density >1.8 g cm-3), and 12.2 ± 0.3% of lignin-derived C vs 6.4 ± 0.1% of litter C accrued in clay-sized (<2 μm) MAOM. Longer anaerobic pretreatments increased added lignin-derived C associated with Fe, according to extractions and nanoscale secondary ion mass spectrometry (NanoSIMS). Microbial residues are important, but lignin-derived C may also contribute disproportionately to MAOM relative to bulk litter-derived C, especially following redox-sensitive biogeochemical interactions.

Monolignol lithium cation basicity estimates and lithium adduct ion optimized geometries

Mass spectrometric analysis of lignin for developing biomaterials requires advances of characterization techniques. Positive ion mass spectrometry of lignin model compounds using lithium has recently been explored as a viable alternative to current negative mode techniques. To date, little is known about the impact of lithium adduct ion formation on relative response factors of lignin and lignin decomposition products. In this contribution, we report estimates of lithium cation basicity for synthetic monolignols H, G and S using Cooks’ kinetic method on a linear quadrupole ion trap mass spectrometer. Optimized geometries and interaction energies have also been calculated by DFT methods to quantify the electrostatic cation coordination. Based on a combination of experimental and computational evidence, lithium appears to preferentially bind to the phenol and methoxy substituents on the aromatic ring of monolignols. The strength of this interaction increases with the number of methoxy substituents (S > G > H). This work serves as a basis of understanding for future work in developing lithium adducted lignin mass spectrometric analytical methods.

Fabrication and environmental applications of multifunctional mixed metal-biochar composites (MMBC) from red mud and lignin wastes.

This study fabricated a new and multifunctional mixed metal-biochar composites (MMBC) using the mixture of two abundant industrial wastes, red mud (RM) and lignin, via pyrolysis under N2 atmosphere, and its ability to treat wastewater containing various contaminants was comprehensively evaluated. A porous structure (BET surface area = 100.8 m2 g-1) was created and metallic Fe was formed in the MMBC owing to reduction of Fe oxides present in RM by lignin decomposition products during pyrolysis at 700 °C, which was closely associated with the transformation of liquid to gaseous pyrogenic products. The potential application of the MMBC was investigated for the removal of heavy metals (Pb(II) and Ni(II)), oxyanions (As(V) and Cr(VI)), dye (methylene blue), and pharmaceutical/personal care products (para-nitrophenol and pCBA). The aluminosilicate mineral, metallic Fe, and porous carbon matrix derived from the incorporation of RM and lignin contributed to the multifunctionality (i.e., adsorption, chemical reduction, and catalytic reaction) of the MMBC. Thus, engineered biochar composites synthesized from selected industrial wastes can be a potential candidate for environmental applications.

Lignin recovery from spent alkaline pulping liquors using acidification, membrane separation, and related processing steps: A Review

The separation of lignin from the black liquor generated during alkaline pulping is reviewed in this article with an emphasis on chemistry. Based on published accounts, the precipitation of lignin from spent pulping liquor by addition of acids can be understood based on dissociation equilibria of weak acid groups, which affects the solubility behavior of lignin-related chemical species. Solubility issues also govern lignin separation technologies based on ultrafiltration membranes; reduction in membrane permeability is often affected by conditions leading to decreased solubility of lignin decomposition products and the presence of colloidal matter. Advances in understanding of such phenomena have potential to enable higher-value uses of black liquor components, including biorefinery options, alternative ways to recover the chemicals used to cook pulp, and debottlenecking of kraft recovery processes.

Methanogenic fermentation of lignite with carbon-bearing additives, inferred from stable carbon and hydrogen isotopes

Lignite from the Konin area (Poland) was used as a substrate for incubation experiments to evaluate its potential for simulation of biogenic methane production. Lignite was incubated with a bacterial inoculum enriched from lake sediments, mineral media, and various supplemental components for microbial life. Additives, such as acetate, methanol, glucose, nutrient broth, and yeast extract, can significantly increase methane production. At the same time, biodegradation of these additional carbon sources leads to overestimation of methane yield. In this paper, selected geochemical properties (total organic carbon content; stable isotopic composition of carbon δ13C) were analyzed in order to evaluate changes in the organic matter of fermented lignite. Stable isotope analysis of carbon and hydrogen was applied in order to identify sources of methane and carbon dioxide formation. TOC decreased in range from 1.4 to 9.6% in lignite after fermentation. The δ13C value of lignite used in the experiments (−25.2‰) decreased after incubation to values in range from −27.1 to −26.2‰. Methane yield per g of TOC (lignite + organic carbon in nutrients) ranged from 0.47 to 2.60mM/g. Glucose, acetate, and methanol significantly increased biogas production. Nutrient broth and yeast extract were not a source of organic carbon for methane formation, but their presence enhanced biogas production. Values of δ13C(CH4) and δ2H(CH4) across incubation conditions ranged from −70.2 to −24.2‰ and from −396.6 to −290.5‰, respectively. Values of δ13C(CO2) ranged from –55.2 to 45.0‰. The high level of variation of δ13C(CH4) and δ13C(CO2) suggests mixing of gases from different carbon sources during incubation, but can also be caused by mixing of metabolic modes by the microbial community. Understanding the δ2H(CH4) variation is even more difficult than the δ13C(CH4) and δ13C(CO2), since many substrates often contain exchangeable hydrogen (e.g. in water, lignite, and elements of nutrients). The combined values of δ13C(CH4) and δ13C(CO2) suggests that the dominant methanogenesis pathway in our experiments may be acetate fermentation. In biodegraded lignite, high relative concentrations of p-cresol (one of the most abundant in the sample) and n-(2-acetylphenyl)formamide were identified. These compounds are most probably lignin decomposition products, or, in the case of the latter, bacterial by-products or remnants. Organic compounds with low molecular weights, n-alkanes, and biomolecules including ferruginol, sugiol, and 6,7-dehydroferruginol, as well as amyrins and tocopherols, were preferentially degraded. The potential for methane production from lignite spiked with carbon-bearing additives is at least one magnitude lower than that from agricultural wastes. The lignite utilization as the single substrate for methanogenic fermentation is economically unprofitable. Mixing of lignite with the external substrate as biomass may be an alternative for consideration and future research.

Development and characterization of a thermophilic, lignin degrading microbiota

Microbial communities and associated enzymes that hydrolyze lignocellulose in the presence of lignin decomposition products are important for industrial and environmental bioconversion processes. The aims of this study were to identify microorganisms capable of decomposing lignocellulose and tolerating lignin decomposition products under high-solids and thermophilic conditions, and to elucidate potential mechanisms of tolerance. High-solids incubations were conducted to enrich for thermophilic communities that decompose Douglas fir. Bacterial and fungal communities were determined using 16S rRNA and ITS region gene sequencing, and PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) was applied to predict genes involved in lignocellulose degradation and tolerance to lignin decomposition products. Lignin decomposition increased with enrichment of specific microorganisms. The dominant bacterium identified with enrichment was from the genus Rubrobacter while the dominant fungus was from the genus Talaromyces. Bacteria containing predicted genes associated with lignin degradation and tolerance to breakdown products were identified. These included organisms from the genus Rubrobacter, and families Beijerinckiaceae and Xanthomonadaceae. The dominant bacteria and fungi identified may be promising sources of enzymes that degrade lignocellulose and genes that confer tolerance to lignin decomposition products.

Molecular tracers preserved in Lower Jurassic “Blanowice brown coals” from southern Poland at the onset of coalification: Organic geochemical and petrological characteristics

The petrographic and molecular characteristics of the Pliensbachian–Toarcian “Blanowice brown coals” and associated sediments are described. These coals are generally dominated by vitrain macerals, although in one sample the inertinite is>60%. This is interpreted as a result of wildfire or peat fire activity which was confirmed by the co-occurrence of charcoal fragments and elevated relative concentrations of unsubstituted PAHs in the samples. Vitrinite reflectance values are in the range of 0.49–0.56%Ro and the C content varies from 30.3–61.9%, placing the coals within the sub-bituminous coal group. However, detailed characterization of coal extracts revealed their highly immature character, based on the occurrence of phenolic abietanes such as ferruginol, sugiol and 7-oxototarol, as well as other biomolecules including labdanoic acid, cholesterol and sitosterol. This is one of the first descriptions of natural product compounds in Jurassic sedimentary rocks. Moreover, in addition to typical lignin decomposition products, dicarboxylic acids with a preponderance of succinic acid were identified. To the best of our knowledge free dicarboxylic acids have not been reported previously from coal extracts. These acids are characteristic resin constituents. We speculate that a low (ca. 40–50°C), but long-term, temperature influence led to an increased vitrinite reflectance values ca. 0.55%Ro, with only minor changes to the composition of unstable biomarkers and biomolecules. Moreover, the resin matrix could protect unstable compounds against geochemical structural alteration. Vitrinite reflectance values may also be elevated due to oxidation which caused paler in colour reaction rims. The presence of phenolic abietanes and the absence of abietic and dehydroabietic acids suggest that the Cupressaceae and/or Podocarpaceae families were the most likely peat-forming plant species.

Pyrolysis reaction characteristics of Korean pine (Pinus Koraiensis) nut shell

This paper elucidates the pyrolysis characteristics of waste Korean pine, Pinus Koraiensis, nut shell (KPNS). Thermogravimetric analysis was performed for kinetic analysis. Pyrolyzer–gas chromatography/mass spectrometry (Py–GC/MS) was used to analysis the product distributions. In line with the kinetic analysis results, the evolved gas analysis–MS (EGA–MS) results clearly showed that the pyrolysis reaction of waste KPNS can be characterized by three independent reactions of hemicellulose, cellulose and lignin followed by a stabilization reaction of solid intermediates formed by a pyrolysis reaction of the three major components. The multi shot-GC/MS results showed that there are specific compounds from the pyrolytic decomposition of the three major components. Acetic acid, levoglucosan, and phenol compounds were the specific decomposition products of hemicellulose, cellulose, and lignin, respectively. The extract ion thermograms suggested that the lignin of waste KPNS is likely to decompose first to yield lignin monomer and intermediates. The monomer appears to have been converted to guaiacols (eugenol and 4-vinylguaiacol), which are decomposed further to produce pyrocatechols, cresols and phenols. The intermediates were also decomposed to pyrocatechols, cresols, and phenols. At the higher temperature region (>600°C), aromatics were released due to the stabilization process of the solid intermediate to yield char.

Conversion of phenyl methyl ethers byDesulfitobacteriumspp. and screening for the genes involved

Microbial growth coupled to O-demethylation of phenyl methyl ethers, which are lignin decomposition products, was described for acetogenic bacteria and recently also for two species belonging to the nonacetogenic genus Desulfitobacterium. To elucidate the potential role of desulfitobacteria in the O-demethylation of phenyl methyl ethers in the environment, we cultivated Desulfitobacterium chlororespirans, D. dehalogenans, D. metallireducens, and different strains of D. hafniense with phenyl methyl ethers as sole electron donors. With the exception of D. metallireducens, all species and strains tested were able to demethylate at least three of the four phenyl methyl ethers applied with fumarate, nitrate, or thiosulfate as electron acceptor. Furthermore, a high number of operons putatively encoding demethylase systems were identified in the genomes of Desulfitobacterium spp., although discrimination between O-, S-, N- and, Cl-demethylases was not possible. These findings provide evidence for the importance of the methylotrophic metabolism for desulfitobacteria and point to their involvement in the O-demethylation of phenyl methyl ethers in the environment.

Possibilities of the Formation of Enol-Ethers in Lignin by Soda Pulping

In the alkaline decomposition of a β-O-4 type lignin model compound (erythro-guaiacylglycerol-β-guaiacyl ether, compound 1), an isomeric pair of C6C2 enol-ether (2-methoxy-4-[2-(2-methoxyphenoxy)-vinyl]-phenol, compound 2) was detected as the main decomposition product with no trace of C6C3 enol-ether (4-[3-hydroxy-1-(2-methoxyphenoxy)-propenyl]-2-methoxy-phenol, compound 3) or other dimers. In contrast, compound 2 was not detected in the alkaline decomposition products of compound 3. Under alkaline conditions, the γ-hydroxymethyl group of compound 3 was reduced to form 2-methoxy-4-[1-(2-methoxyphenoxy)-propenyl]-phenol (compound 4). In the HSQC analysis of soda lignin, the formation of substructures of C6C2 type enol-ether (related to compound 2) was confirmed. However, no substructures related to compound 4, which could be formed if a substructure of C6C3 type enol-ether was formed under alkaline conditions, were detected. Therefore, it could be concluded that C6C3 type enol-ethers could not be intermediates of alkaline decomposition products of lignin.

Hydrothermal decomposition of alkali lignin in sub- and supercritical water

Alkali lignin as an example of waste plant biomass was subjected in a batch reactor to decomposition in sub- and supercritical water. Hydrothermolysis of alkali lignin with relatively highmolecular-weight led to the production of phenolic compounds such as guaiacol and catechol, as well as phenol, m-cresol, p-cresols and o-cresol. Both an increase growth in conversion time and an increase in reaction temperature promoted secondary reactions: degradation of alkali lignin decomposition products, leading to, their repolymerization and carbonization. The components of the liquid fractions of products were examined by GC–MS and HPLC, whereas the solid charred post-reaction residues were analyzed by elemental analysis and FTIR.

Thermal analysis/mass spectrometry using soft photo-ionisation for the investigation of biomass and mineral oils

Abstract The combined analytical methods of thermal analysis and mass spectrometry have been applied in form of a newly developed prototype of a thermogravimetry — single photon ionisation time-of-flight mass spectrometer coupling (TG-SPI-TOFMS) to investigate the molecular patterns of evolved gases from several biomass samples as well as a crude oil sample. Single photon ionization (SPI) was conducted by means of a novel electron beam pumped argon excimer lamp (EBEL) as photon source. With SPI-TOFMS various lignin decomposition products such as guaiacol, syringol and coniferyl alcohol could be monitored. Furthermore, SPI allows the detection of aliphatic hydrocarbons, mainly alkenes, carbonylic compounds such as acetone, and furan derivatives such as furfuryl alcohol and hydroxymethylfurfural. More alkaline biomass such as coarse colza meal show intense signals from nitrogen containing substances such as (iso-)propylamine and pyrrole. Thermal degradation of crude oil takes place in two steps, evaporatio...

Influence of particle size on the analytical and chemical properties of two energy crops

Two energy crops (switchgrass and reed canary grass) have been processed using ball mills and divided into two size fractions (<90 μm and 90–600 μm) and analysed using an array of analytical techniques including proximate and ultimate analysis, metal analysis, calorific value determination, and plant component analysis (cellulose, lignin and hemicellulose contents). The results indicate that smaller particles of the two grasses have a significantly higher concentration of inorganic matter and moisture content than larger particles. In contrast the larger size fractions had a higher carbon content, and lower nitrogen content, with a resulting higher calorific value. The volatile content was also higher in the larger size fraction. The composition of the organic content varied between the two size fractions, most noticeable was the difference in cellulose concentration which was approximately 50% higher in the >90 μm sample. Two laboratory scale techniques, thermogravimetric analysis (TGA) and pyrolysis–GC–MS (py–GC–MS), were used to study the significance of these differences in thermal conversion. In py–GC–MS of reed canary grass, and switchgrass to a lesser extent, the amounts of cellulose and lignin decomposition products were higher for the larger particle size fraction. The differences in cellulose contents were also apparent from the TGA studies, where different mass losses were seen in the cellulose decomposition region of the two size fractions. From the results of these two techniques it was concluded that the differences in ash, and therefore catalytic metal contents, between the two size fractions, resulted in lower pyrolysis temperatures, lower char combustion temperatures, and higher yields of catalytic pyrolysis decomposition products for the smaller size fractions. The implications of the results are discussed in terms of the bio-oil quality in fast pyrolysis and the predicted behaviour of the ash in combustion. It is suggested that pre-treatment by milling is one route that might be used routinely as a feedstock quality improvement strategy in integrated biomass conversion processes.

Lignin turnover kinetics in an agricultural soil is monomer specific

Lignin transformation and decomposition products are generally considered a major source of stable soil organic matter (SOM). Nevertheless this process remains poorly understood in part because lignin is a heterogeneous biopolymer composed of several types of phenol monomers, which potentially display specific and contrasting decomposition kinetics in soils. Here, we compared the specific in situ turnover kinetics of individual lignin monomers in a Paris-basin loamy soil through natural 13C labeling of SOM generated in a series of 1–9-year chronosequences of maize monoculture (C4, δ 13C −12‰) replacing wheat (C3, −27‰). Lignin monomers were released by CuO oxidation, quantified by gas chromatography (GC)/flame ionization detection (FID) and their 13C content was determined by GC coupled via a combustion interface to isotope ratio mass spectrometry (GC/C-IRMS). We calculated the proportion of C4-derived OC in lignin monomer pools by applying the isotopic mass balance equation to each lignin monomer. Individual C4-derived phenols displayed contrasting accumulation rates in soils over time, confirming the monomer-specific nature of their transformation kinetics. In proportion to total lignin phenols in soils, syringyl (S) and cinnamyl (C) phenols from maize accumulated faster than their vanillyl (V) counterparts. Consequently, the turnover kinetics of lignin-derived V-moieties may be slower than those of S and C ones. Incorporation of maize-derived carbon was faster in the aldehyde than in the acid pool for V-type units, while the opposite was observed for S-units. These in situ trends for phenol monomers and V-, S- and C-moieties were remarkably similar to the trends described in the literature with laboratory incubation or litterbag studies. None of the observed kinetics had a linear shape. Using only the extreme points of the chronosequence to calculate the kinetic parameters would result, for all the lignin monomers, in underestimating the turnover kinetics at the beginning of the kinetics and overestimating it for longer times. This observation underlines the importance of comprehensive 13C time-sequence labelling experiments such as provided at the Closeaux site, to accurately compute the kinetic parameters of SOM for the 1st years after the vegetation change.

Influence of coarse wood and fine litter on forest organic matter composition

Forest soil organic matter (SOM) is affected by inputs from coarse wood (CW) and fine litter (FL, e.g., leaves, twigs, cones, and needles). The influence of these materials on forest SOM was studied in a lodgepole pine (Pinus contorta) forest in southeastern Wyoming. Organic materials in CW sites were significantly (P &lt; 0.05) more acidic, but contained half the total N of FL sites. Forest floor materials and SOM C contents were significantly greater in CW samples. Lignin decomposition products (CuO analysis) accumulated primarily in organic horizons of both sites, with significantly higher (60–70%) contents in CW materials. Vanillyl compounds were the primary lignin products from both sites, with cinnamyl compounds also important in SOM from FL sites. Vanillic acid to vanillin ratios were significantly higher in mineral soils under CW. 13C-NMR spectra indicated CW materials were enriched in lignin, and that humic acids from both site types were very similar and unusually high in alkyl C. Fulvic acids were also high in O-alkyl and carboxyl C, particularly in the CW sites. Results suggest there are differences in forest C constituents and that removal of CW could possibly alter forest soil dynamics that would impact forest productivity and biodiversity. Key words: Forest, coarse wood, litter, carbon, soil organic matter, humic substances

Sorption of sulfonamide pharmaceutical antibiotics on whole soils and particle-size fractions.

Residues of pharmaceutical antibiotics are found in the environment, whose fate and effects are governed by sorption. Thus, the extent and mechanisms of the soil sorption of p-aminobenzoic acid and five sulfonamide antibiotics (sulfanilamide, sulfadimidine, sulfadiazine, sulfadimethoxine, and sulfapyridine) were investigated using topsoils of fertilized and unfertilized Chernozem and their organic-mineral particle-size fractions. Freundlich adsorption coefficients (K(f)) ranged from 0.5 to 6.5. Adsorption increased with aromaticity and electronegativity of functional groups attached to the sulfonyl-phenylamine core. Adsorption to soil and particle-size fractions increased in the sequence: coarse silt < whole soil < medium silt < sand < clay < fine silt and was influenced by pH. Sorption nonlinearity (1/n </= 0.76) indicated specific interactions with functional groups of soil organic matter (SOM). Phenolic and carboxylic groups, N-heterocyclic compounds, and lignin decomposition products were tentatively assigned as preferred binding sites using statistical analysis of pyrolysis-mass spectra and adsorption coefficients. Adsorption of sulfonamides to mineral soil colloids was weaker and resulted in a stronger desorption from clay-size fractions. Moreover, steric accessibility of organic-mineral complexes in clay-size fractions was significantly reduced. With a quantitative structure-property relationship (QSPR) model, combining the organic carbon concentration, the sulfonamides' chromatographic capacity factor (k'), and nondissociated species concentration (CF(a)), distribution coefficients (K(d)) were estimated with a cross-validated regression coefficient Q(2) = 0.71. Modeling and molecular mechanics calculations of antibiotic-SOM complexes showed preferred site-specific sorption via hydrogen bonds and van der Waals interactions. Distinct chemical structural properties, such as aromaticity and van der Waals volumes, correlated with the sorption data.

Sources of Fine Organic Aerosol. 9. Pine, Oak, and Synthetic Log Combustion in Residential Fireplaces

Combustion of wood in residential fireplaces contributes approximately 14% on an annual average of the total primary fine particle organic carbon (OC) emissions to the Los Angeles urban atmosphere and up to 30% of the fine particulate OC emissions on winter days. This paper presents comprehensive organic compound source profiles for smoke from burning pine, oak, and synthetic logs in residential fireplaces. Mass emission rates are determined for approximately 200 organic compounds including suites of the n-alkanes, n-alkenes, cyclohexylalkanes, n-alkanals, n-alkanoic acids, alkenoic acids, dicarboxylic acids, resin acids, hydroxylated/methyoxylated phenols, lignans, substituted benzenes/benzaldehydes, phytosterols, polycyclic aromatic hydrocarbons (PAHs), and oxy-PAHs. Wood smoke constituents reflect to a great extent the underlying composition of the wood burned: pine and oak logs produce smoke that is enriched in lignin decomposition products, pine smoke is enriched in resin acids and their thermal alteration products, while smoke from the synthetic log burned here bears the major signature of the petroleum products combined with traces of the sawdust components from which it is made. Resin acids are discussed as potential wood smoke tracers in the environment, and it is shown that the time series of resin acids concentrations in the Los Angeles atmosphere follows the extreme seasonal variation in wood use reported in previous emissions inventories for the Los Angeles urban area.

Organic Matter Composition in Organic-Mineral Soil Particles

The intimate association of organic and mineral soil constituents to form organic-mineral complexes is one of the most important soil characteristics as it affects almost all physical, chemical and biological, soil properties. Therefore, the composition and functions of soil organic matter (SOM) in organic-mineral soil particles are subject to intensive research. According to pre-treatment and isolation techniques we can distinguish investigations of (1) particle-size, (2) density and (3) aggregate fractions. Methodical approaches applied were (1) wet-chemical analyses (contents of carbohydrates, lignin decomposition products, N-containing compounds, lipids), (2) noninvasive spectroscopy (solid-state ~3C-NMR), and (3) combinations of pyrolysis with gas-chromatography/ mass spectrometry (GC/MS) and field-ionization mass spectrometry (FI-MS). This contribution gives the state of knowledge about organic matter composition in soil fractions of different size, density and spatial arrangement (aggregates).