Gerald Jandl

Quantification of long-chain fatty acids in dissolved organic matter and soils

The objective was to develop and adapt a versatile analytical method for the quantification of solvent extractable, saturated long-chain fatty acids in aquatic and terrestrial environments. Fulvic (FA) and humic (HA) acids, dissolved organic matter (DOM) in water, as well as organic matter in whole soils (SOM) of different horizons were investigated. The proposed methodology comprised extraction by dichloromethane/acetone and derivatization with tetramethylammonium hydroxide (TMAH) followed by gas chromatography/mass spectrometry (GC/MS) and library searches. The C10:0 to C34:0 methyl esters of n-alkyl fatty acids were used as external standards for calibration. The total concentrations of C14:0 to C28:0n-alkyl fatty acids were determined in DOM obtained by reverse-osmosis of Suwannee river water (309.3 μg g—1), in freeze-dried brown lake water (180.6 μg g—1), its DOM concentrate (93.0 μg g—1), humic acid (43.1 μg g—1), and fulvic acid (42.5 μg g—1). The concentrations of the methylated fatty acids (n-C16:0 to n-C28:0) were significantly (r2 = 0.9999) correlated with the proportions of marker signals (% total ion intensity (TII), m/z 256 to m/z 508) in the corresponding pyrolysis-field ionization (FI) mass spectra. The concentrations of terrestrial C10:0 to C34:0n-alkyl fatty acids from four soil samples ranged from 0.02 μg g—1 to 11 μg g—1. The total concentrations of the extractable fatty acids were quantified from a Podzol Bh horizon (26.2 μg g—1), Phaeozem Ap unfertilized (48.1 μg g—1), Phaeozem Ap fertilized (57.7 μg g—1), and Gleysol Ap (66.7 μg g—1). Our results demonstrate that the method is well suited to investigate the role of long-chain fatty acids in humic fractions, whole soils and their particle-size fractions and can be serve for the differentiation of plant growth and soil management. Quantifizierung von langkettigen Fettsauren in gelostem organischen Material und in Boden Das Ziel der Arbeit war es, eine vielseitige analytische Methode zur Quantifizierung von extrahierbaren langkettigen Fettsauren in der aquatischen und terrestrischen Umwelt zu entwickeln und anzupassen. Dazu wurden Fulvo- (FA) und Huminsauren (HA), geloste organische Substanzen (DOM) aquatischer Proben sowie organische Bodensubstanzen (OBS) von Feinboden-Proben verschiedener Horizonte untersucht. Die vorgeschlagene Methodik besteht aus der Extraktion der Proben mit Dichlormethan/Aceton, Derivatisierung mit Tetramethylammoniumhydroxid (TMAH) sowie Gaschromatographie/Massenspektrometrie (GC/MS) und Bibliothekssuche. Als externer Standard wurden die Methylester der C10:0 bis C34:0n-Alkylfettsauren verwendet. Die Gesamt-Kon-zentrationen der C14:0 bis C28:0 n-Alkylfettsauren wurden in DOM aus dem Suwannee River nach Umkehr-Osmose (309,3 μg g—1) sowie in unterschiedlich behandelten Proben aus einem Hochmoorsee, wie DOM nach Gefriergetrocknung (180,6 μg g—1), DOM-Konzentrat nach Umkehr-Osmose (93,0 μg g—1) sowie Huminsaure (43,1 μg g—1) und Fulvosaure (42,5 μg g—1) ermittelt. Die Konzen-trationen der methylierten Fettsauren (n-C16:0 bis n-C28:0) mit den Anteilen der Marker-Signale (% Totalionenintensitat (TII), m/z 256 bis m/z 508) der korrespondierenden Pyrolyse-Feldionisation (FI) Massenspektren korrelieren mit einem Koeffizienten (r2) von 0,9999. Die Konzentrationen der einzelnen C10:0 bis C34:0n-Al-kylfettsauren von vier Bodenproben lagen zwischen 0,02 μg g—1 und 11 μg g—1. Die Gesamt-Konzentrationen der extrahierbaren Fett-sauren wurden bestimmt in einem Podsol-Bh (26,2 μg g—1), Braunerde-Tschernosem-Ap, ungedungt (48,1 μg g—1), Braunerde-Tschernosem-Ap, gedungt (57,7 μg g—1) und Gley-Ap (66,7 μg g—1). Unsere Resultate zeigen, dass die vorgeschlagene Methodik gut geeignet ist, die Gehalte von langkettigen Fettsauren in Huminstoff-Fraktionen, Gesamtboden und deren Partikelgrosen-Fraktionen zu bestimmen und somit ihre Bedeutung fur Bodenqualitat und Pflanzenwachstum zu erforschen.

The conversion of chicken manure to biooil by fast pyrolysis II. Analysis of chicken manure, biooils, and char by curie-point pyrolysis-gas chromatography/mass spectrometry (Cp Py-GC/MS)

The initial chicken manure and the three fractions derived from it by fast pyrolysis, that is, the two biooils Fractions I and II as well as the residual char were analyzed by Curie-point pyrolysis-gas chromatography/mass spectrometry (Cp Py-GC/MS). The individual compounds identified were grouped into the following six compound classes: (a) N-heterocyclics; (b) substituted furans; (c) phenol and substituted phenols; (d) benzene and substituted benzenes; (e) carbocyclics; and (f) aliphatics. Of special interest were the relatively high concentrations of N-heterocyclics in biooil Fraction II which was obtained in the highest yield and had the highest calorific value. Prominent N-heterocyclics in biooil Fraction II were methyl-and ethyl-substituted pyrroles, pyridines, pyrimidine, pyrazines, and pteridine. Also noteworthy was the high abundance of aliphatics in biooil Fraction I and the char. The alkanes and alkenes in biooil Fraction I ranged from n-C7 to n-C18 and C7:1 to C18:1, respectively, and those in the char from n-C7 to n-C19 and C7:1 to C19:1, respectively. The N-heterocyclics in the two biooil Fractions came from the chicken manure, from proteinaceous materials during fast pyrolysis or were formed during the fast pyrolysis manure conversion by the Maillard reaction which involved the formation of N-heterocyclics by amino acids interacting with sugars.

Origin and fate of soil lipids in a Phaeozem under rye and maize monoculture in Central Germany

Although soil lipids are an important class of soil organic substances, which is involved in numerous soil processes, their origin and fate in soils is insufficiently known. Therefore, this study aimed at investigating the free lipid fraction in crop residues and farmyard manure (FYM), and soils which received these materials for long time. We sampled rye and maize stubble and roots, FYM, and Ap horizon soils from the ‘Unfertilized’ and ‘FYM’ plots of ‘Eternal Rye Cultivation’ experiment at Halle, Saxony-Anhalt, Germany. Free lipids were extracted by dichloromethane/acetone and analyzed by gas chromatography/mass spectrometry. Aliphatics were most abundant in all extracts, accounting for 61 to 77% of the total extractable lipids. By comparing the lipid composition of the added organic materials with that of the corresponding treated soil, the long-chain members of n-alkanols, n-alkanes, α,ω-alkanedioic acids, and unsaturated alkanoic acids from C16 to C19 did not disappear in soil whereas ω-hydroxyalkanoic acids and long-chain branched alkanoic acids were not extracted from soil probably because they were bound to nonextractable forms. It is suggested that the methodological approach can give information on decomposition and retention of free extractable lipids in soil. More information is needed to trace the fate of all lipids in the plant–soil system by the determination of bound molecules, which are nonextractable by organic solvents.

Advances in Understanding Organic Nitrogen Chemistry in Soils Using State-of-the-art Analytical Techniques

Abstract During the past decade, soil and geochemists have adopted a variety of novel chemical–analytical methods to explore the chemistry of soil organic N (N org ). This chapter summarizes some of the more recent developments in the use of wet-chemical and instrumental methods to determine total N org concentrations as well as to speciate the N org in soils. A critical evaluation of 15 N nuclear magnetic resonance (NMR) spectroscopy found the technique to be wanting, in terms of its sensitivity and ability to identify classes of N org compounds in soils. Complementary mass spectrometric techniques are described briefly, and improved data evaluations based on broad applications of high-resolution pyrolysis-field ionization mass spectrometry are presented and discussed. A reassessment of older data sets using the new spectral evaluation algorithms provides strong evidence of fire- and management-induced changes in N org speciation. Isotope-ratio mass spectrometry, Fourier transform ion cyclotron resonance mass spectrometry, and nanoscale secondary ion mass spectrometry (Nano-SIMS) also are discussed, with the latter two techniques having potential to (1) identify N org compounds and (2) provide spatially resolved information on the molecular, elemental and isotopic composition of soil N org . The use of 15 N labeling techniques is discussed both from a methodological standpoint and in terms of tracking the fate of plant-derived (residue or rhizodeposit) N in the soil. Indeed, coupling 15 N labeling with analytical techniques such as 15 N NMR, Nano-SIMS and high- or ultrahigh-resolution mass spectrometry can provide information on how N is incorporated into soil organic matter. Analytical and instrumental innovations have resulted in new insights into the chemistry of N org —together with a revised summary of the relative amounts of the different N org compound classes present in soils (e.g. aliphatic amine and amide N, aromatic heterocyclic N), as well as their ecophysiological functions. Particular emphasis is given to the use of multitechnique analyses and the outstanding molecular–chemical diversity of biogenic heterocyclic N org compounds. Examples are given of the new insights obtained using multi-analytical research approaches to explore microbial utilization of heterocyclic N and organic–mineral interactions, as well as the ability of human and environmental intervention to alter the composition of soil N org . Finally, we examine future challenges and propose analytical approaches to tackle open questions regarding the basic chemistry and cycling of N org in soils, as well as the agronomic and environmental consequences associated with N transformations in agro-ecosystems.

Hydrothermal carbonization of biomass residues: mass spectrometric characterization for ecological effects in the soil-plant system

Hydrochars, technically manufactured by hydrothermal carbonization (HTC) of biomass residues, are recently tested in high numbers for their suitability as feedstock for bioenergy production, the bioproduct industry, and as long-term carbon storage in soil, but ecological effects in the soil-plant system are not sufficiently known. Therefore, we investigated the influence of different biomass residues and process duration on the molecular composition of hydrochars, and how hydrochar addition to soils affected the germination of spring barley ( L.) seeds. Samples from biomass residues and the corresponding hydrochars were analyzed by pyrolysis-field ionization mass spectrometry (Py-FIMS) and gaseous emissions from the germination experiments with different soil-hydrochar mixtures by gas chromatography/mass spectrometry (GC/MS). The molecular-level characterization of various hydrochars by Py-FIMS clearly showed that the kind of biomass residue influenced the chemical composition of the corresponding hydrochars more strongly than the process duration. In addition to various detected possible toxic substances, two independent mass spectrometric methods (Py-FIMS and GC/MS) indicated long C-chain aliphatic compounds which are typically degraded to the C-unit ethylene that can evoke phytotoxic effects in high concentrations. This showed for the first time possible chemical compounds to explain toxic effects of hydrochars on plant growth. It is concluded that the HTC process did not result in a consistent product with defined chemical composition. Furthermore, possible toxic effects urgently need to be investigated for each individual hydrochar to assess effects on the soil organic matter composition and the soil biota before hydrochar applications as an amendment on agricultural soils.

The conversion of chicken manure to bio-oil by fast pyrolysis. III. Analyses of chicken manure, bio-oils and char by Py-FIMS and Py-FDMS

Fast pyrolysis of chicken manure produced the following three fractions: bio-oil Fraction I, bio-oil Fraction II, and a char. In a previous investigation we analyzed each of the four materials by curie-point pyrolysis-gas chromatography/mass spectrometry (CpPy-FDMS). The objective of this article is to report on the analyses of the same chicken manure and the three fractions derived from it by fast pyrolysis. We now used pyrolysis-field ionization mass spectrometry (Py-FIMS) to characterize the three fractions. In addition, the two bio-oil materials were analyzed by pyrolysis-field desorption mass spectrometry (Py-FDMS). The use of both Py-FIMS and Py-FDMS produced signals over significantly wider mass ranges than did CpPy-GC/MS, and so allowed us to identify considerably larger numbers of constituents in each material. Individual compounds identified in the mass spectra were classified into the following twelve compound classes: (a) low molecular weight compounds (< m/z 62); (b) carbohydrates; (c) phenols + lignin monomers; (d) lignin dimers; (e) n-alkylbenzenes; (f) N-heterocyclics; (g) n-fatty acids; (h) n-alkanes; (i) alkenes; (j) sterols; (k) n-diols and (l) high molecular weight compounds (> m/z 562). Of special interest were the high abundances of low-molecular weight compounds in the two bio-oils which constituted close to one half of the two bio-oils. Prominent among these compounds were water, ammonia, acetic acid, acetamide, propyl radical, formamide and hydrogen cyanide. The main quantitative differences between the two bio-oils was that bio-oil Fraction I, as analyzed by the two mass spectrometric methods, contained lower concentrations of low-molecular weight compounds, carbohydrates, and N-heterocyclics than bio-oil Fraction II but was richer in lignin dimers, n-alkylbenzenes and aliphatics (n-fatty acids, n-alkanes, alkenes, and n-diols). Of special interest were the N-heterocyclics in the two bio-oils such as pyrazole, pyrazoline, substituted pyrroles, pyridine and substituted pyridines, substituted methoxazole, substituted pyrazines, indole and substituted indoles. Fatty acids in all four materials ranged from n-C9 to n-C33, alkanes from n-C9 to n-C40, alkenes from C10:1 to C40:1 and diols from n-C7 to n-C29. The chicken manure, bio-oil Fraction I, and char each contained about 4% sterols with cholesterol, ethylcholestriene, ergosterol, ethylcholestene, ethylcholesterol and β -sitosterol as major components. Semi-quantitative estimates of the total materials identified by Py-FIMS were: chicken manure: 61.1%; bio-oil Fraction I: 81.3%; bio-oil Fraction II: 78.6%; char: 61.3%; and by Py-FDMS were: bio-oil Fraction I: 65.4%; bio-oil Fraction II: 70.0%.

Nitrogen speciation in fine and coarse clay fractions of a Cryoboroll - new evidence from pyrolysis-mass spectrometry and nitrogen K-edge XANES

Soil clay fractions are usually enriched in nitrogen (N), but the chemical identity of this N is largely unknown. Therefore, we investigated organic N in fine and coarse clay of a clay-rich Cryoboroll by Curie-point pyrolysis-gas chromatography/mass spectrometry (Cp Py-GC/MS), Pyrolysis-field ionization mass spectroscopy (Py-FIMS) and synchrotron-based nitrogen K-edge X-ray absorption near edge structure (N-XANES) spectroscopy. The Cp Py-GC-MS revealed 30 structurally different N-containing compounds, such as substituted pyridines, pyrroles; pyrazines, pyrazoles, imidazoles, quinolines, side-chain N-containing benzenes, and single compounds of substituted benzotriazole, purine and indole. These accounted for about 10% of peak area in the Py-GC chromatograms. The Py-FIMS and N-XANES spectra indicated interlayer-NH4+ and revealed pyridinic and nitrilic N compounds, but disagreed in the proportions of pyrroles. All three complementary methods confirmed to different extents previous wet-chemical data on N-fra...

The impact of short rotation coppice on the concentrations of aliphatic soil lipids

The aim was to investigate how short rotation coppice (SRC) on arable soil in Northern Germany altered the concentrations of soil lipids, and thus, soil organic matter (SOM) quality. The concentrations of organic C and aliphatic lipids were determined in the litter and underlying soil layers under two willow (Salix caprea × viminalis clone 6, S. viminalis clone 78–183) and two poplar (Populus trichocarpa × deltoides cv. Beaupré, P. nigra × maximowiczii cv. Max 4) clones at a 14-year-old SRC and a permanent arable reference site. High organic C concentrations in the topsoil under S. viminalis and P. trichocarpa × deltoides agreed with high concentrations of long C-chain saturated n-alkanoic acids, n-alkanols and n-alkanes. These disproportionally higher concentrations of long C-chain saturated n-alkanoic acids (factor 3.6) and n-alkanols (factor 3.8) under S. viminalis and of n-alkanols (factor 3.9) under P. trichocarpa × deltoides than in an arable reference treatment indicated a lower microbial decomposability and, thus, a clone-specific accumulation of these SOM constituents. The clone-specific enrichments in long C-chain saturated n-alkanoic acids, n-alkanols and n-alkanes indicate that clone selection may be an approach to additional long-term storage of atmosphere CO2 in the form of stable SOM under SRC.

Compost Changed Soil Organic Matter Molecular Composition: A Py-GC/MS and Py-FIMS Study

Changes in the molecular composition of soil organic matter (SOM) resulting from compost application are not sufficiently known at the molecular scale even though this is a major issue for soil fertility and soil carbon sequestration. Therefore, the present study investigated effects of long-term compost application in comparison to mineral fertilizer on the molecular composition of SOM in a 34-year-old experiment. Soil samples were taken after 19 and 34 years of constant management and analyzed by Curie point Pyrolysis-Gas Chromatography/Mass Spectrometry (Cp Py-GC/MS) and Pyrolysis-Field Ionization Mass Spectrometry (Py-FIMS). In general, compost application increased the organic carbon (C) content. The Cp PyGC/MS revealed larger relative intensities of alkylphenols/lignin monomers at the expense of carbohydrates in the compost treatments. Py-FIMS indicated higher proportions of labile n-fatty acids, lipids and sterols in the compost than in the mineral fertilizer treatment. Permanent cropping of grass between years 19 and 34 revealed similar signal patterns, which is also maintained after conversion of soil from permanent grass to arable use. Thermograms of volatilization indicated enrichments of stable (compounds volatilized in between 370°C and 570°C) phenols/lignin monomers, lipids and alkylaromatics between years 19 and 34 in compost fertilized soils. This was a result of enhanced losses of compounds that are considered easily metabolized by microorganisms (e.g. carbohydrates) after compost addition as derived from Py-GC/MS and Py-FIMS. In summary, long-term application of mature compost was shown to have a positive, long lasting effect on the organic carbon sequestration in agricultural soils.

Crop-specific differences in the concentrations of lipids in leachates from the root zone

Although lipids are involved in diverse soil processes and affect various soil properties, the contribution of rhizodeposits and the root zone to lipid concentrations and distributions in soils is unknown. For the first time, we determined the concentrations of alkanoic acids, n-alkanes and n-alkenes in root zone leachates and roots of maize and potato using gas chromatography/mass spectrometry (GC/MS). In total, the lipid concentrations of leachates were 100 μg g−1 (maize) and 17 μg g−1 (potato). The saturated n-alkanoic acids, ranging from n-C14 to n-C28 and having the maximum at n-C22 (maize) and at n-C16 (potato), were more abundant than the other compounds. Maize leachates had more alkanes (20 μg g−1) than potato leachates (3.1 μg g−1), but the members of the homologues were nearly the same. Comparison of these distributions with data for roots, microorganisms and soil indicated that the lipids in the leachates from the root zone mainly originated from abrasion of fine roots, rhizodeposits and rhizosphere microorganisms.