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A specific, highly sensitive and quantitative pyrolysis-gas chromatography/mass spectrometry-single ion monitoring (Py-GC/MS-SIM) procedure has been developed for dissolved high molecular weight (MW>1000) chlorolignosulfonic acids in sulfite pulp mill effluents, river water, and drinking water. Satisfying reproducibility (average RSD 5%) was obtained using polystyrene as an internal standard. Maximum accuracy was obtained using a standard addition quantification procedure. The detection limit is 16-32 μg/L chlorolignosulfonic acids, corresponding to 0.1-0.2 μg/L adsorbable organic halogen (AOX) and to 10-20 ng/L chloroguaiacyl substructures

Temperature-resolved in-source pyrolysis—mass spectrometry (Py—MS) and complementary Curie-point pyrolysis—gas chromatography/mass spectrometry (Py—GCIMS) were used to characterize a set of lignin polymers. No sample pretreatment was required and over 100 thermal degradation products were identified in the pyrolysates. Results were compared with whole biomass reference materials. Coniferyl alcohol and sinapyl alcohol, which were formed upon pyrolysis of lignin, could be selectively ionized by ammonia chemical ionization (Cl). Curie-point Py—GC with flame ionization detection was applied to classify the lignin polymers according to syringyl/guaiacyl ratios, the number of preserved phenylpropane structural units and functional group content. Multivariate analysis of the in-source Py—MS data was employed to classify the lignin polymers according to the origin and degree of modification. Combined results showed that enzyme-treated cottonwood-milled wood lignin is a relatively homogeneous polymer with a large fraction of preserved alkyl-aryl ether linkages. Technical lignins, isolated by the steam-explosion, organosolv and Kraft pulping processes, were found to be modified depending on the severity of the isolation procedure employed, and contained large amounts of β — 1-linked stilbene and β — β-linked resinol types of structures. Bagasse lignin shows the most condensed polymer structure with a large proportion of ether bonded p -coumaric acid and ferulic acid.

As a model for polysaccharide char formation in archaeological food residues, bulk samples of microcrystalline cellulose were charred under anoxic conditions at atmospheric pressure and at temperatures ranging from 190 to 310°C. The resulting chars were characterised by pyrolysis—mass spectrometry (Py—MS) and Curie-point pyrolysis—gas chromatography-mass spectrometry (Cu-Py—GC/MS). Although very few polysaccharide moieties were preserved in the experimental chars after heating above 270°C, a characteristic distribution of pyrolysis products representing the condensed char is shown. A selected charred archaeological food residue was analysed using the same analytical techniques. In this way, polysaccharide input can be detected in archaeological residues after approximately 1800 years of burial.

Primary pyrolysis mechanisms for native cellulose are more universally applicable, which is illustrated by the analyses of the characteristic pyrolysis product distributions of O-(2-hydroxyethyl)celluloses (HECs) measured by in-source pyrolysis-ammonia chemical ionisation mass spectrometry (Py-CIMS). The extent of the thermal degradation via transglycosidation, reverse aldolisation and Ei-elimination mechanisms in these cellulose derivatives is strongly influenced by the presence of substituents and by their substitution positions. The transglycosidation mechanism, which is the main thermal degradation pathway of cellulose, is blocked if the 6-O-positions in the cellulose backbone are substituted. The formation of a series of polyethylene glycolaldehydes and polyethylene glycols is explained by the reverse aldolisation and Ei-elimination mechanisms, respectively. The pyrolysis products of HECs have been identified by the determination of the number of hydroxyl groups in the mass peaks, which was done by the comparison of NH3 and ND3 Py-CI mass spectra. The correlation between the pyrolysis product distribution and substituents in HECs is illustrated by a multivariate analysis of the Py-CI mass spectra of 11 HECs, revealing structural information concerning the cellulose character and the average chain length of the substituents in the samples.

Attempts to forge amber inclusions have been known from ancient times, when natural materials such as melted amber or copal were used. At the very beginning of the Twentieth Century these natural materials were mostly replaced by Bakelite and similar synthetic polymers. These materials are not transparent and so can readily imitate certain kinds of milky amber but are useless in terms of transparent ambers with inclusions. In the 1940s two new classes of organic materials became available for amber imitation, i.e. polyester resins and epoxy resins. Both are transparent, able to dissolve organic dyes and can achieve an appropriate degree of hardness, depending on the addition of fillers (e.g. fiberglass), the structure of the original monomers, and the degree of crosslinking. With easy commercial availability and sophisticated “artwork” one can prepare convincing imitations of large transparent amber pieces with a wide variety of “inclusion” (ants, bees, lizards, mosquitos, etc.). Py-GC provides a simple test for the unmasking of such fakes, and Py-GC/MS can identify quite precisely the structures of the materials used for these purposes. A growing number of fossil forgeries produced in the Dominican Republic, and sold there and in New York, have been documented. The results reported are based largely on forgeries acquired by D. Grimaldi specifically for this study and kept at the American Museum of Natural History in New York; and from the Conservation Center's collection of forged artifacts and jewelry made available by New York galleries and private collectors.

Methylation analysis complete with GLC-MS of three O -(2-dhydroxyethyl)celluloses with degrees of molar substitution (ms) of 1.73, 2.44, and 3.56, determined by hydrolysis with hydriodic acid, revealed at least 35 new monomeric compounds. Except for S 33333 , all of the isomers up to the monomers with ms 5 have been identified and quantified by GLC. The ms, degree of substitution (ds), positional, ds and the ms and ds distribution of the monomers have been derived. The resulting ms values were 1.89,2.30, and 3.39, and the ds values were 1.21, 1.34. and 2.06, respectively. The relative reaction constants for HO-2,3,6 have been computed and that for HO-2 appears not to vary. These calculated constants have been used to determine the homogeneity of the substituent distribution.

The 17- to 20-million-year-old locality at Clarkia, northern Idaho, is renowned for yielding amplifiable DNA from a magnolia leaf fossil. In-source pyrolysis-mass spectrometry and pyrolysis-gas chromatography/mass spectrometry now reveal that molecular preservation of biomacromolecules is highly selective; structural polysaccharides, cutin polyesters, and proteins were not preserved in detectable quantity in the leaf tissues, whereas both lignin and an aliphatic biopolymer were detected. This study points up the need for improved understanding of the precise modes and extent of preservation of biomacromolecules in fossil materials and sediments.

An aqueous high-performance size-exclusion chromatographic (HPASEC) method for lignosulphonates was developed and optimized using a TSK G3000SW column. Curie-point pyrolysis—gas chromatography—mass spectrometry (Py—GC—MS) was used to characterize the lignosulphonates on the molecular level. Combined HPASEC and Py—GC—MS results showed that a sodium lignosulphonate standard, prepared under mild conditions, was a relatively polydisperse polymer that still contained features of a natural lignin polymer. Lignosulphonates discharged by pulp mills are more monodisperse macromoles of a relatively low molecular mass and are structurally modified to a greater extent than the sodium lignosulphonate standard. A relationship was established between the molecular mass distributions of the various lignosulphonate macromolecules and the fraction of preserved phenylpropane structural units.

Dissolved chlorolignosulfonic acids and lignosulfonic acids in pulp mill effluents and the river Rhine can be iolated effectively by XAD-8 adsorption chromatography combined with ultrafiltration. Satifying XAD-8 recoveries (55-78% of UV 280 absorbance) of pulp mill effluent, chlorolignosulfonic acid, and lignosulfonic acid are obtained using a sample pH of 1. A 0.1 M NaOH/methanol (50/50 v/v) mixture is recommended as a standard eluent for XAD-8 chromatography because of its quantitative, reproducible, and rapid desorption properties.

Analysis of sections of the seventh internode of a maize stalk by light microscopy revealed phenolic compounds in primary and secondary cell walls. Secondary cell walls were degraded in in vitro digestion experiments. After permanganate oxidation a positive staining with phloroglucinol of the middle lamella-primary wall was observed whereas the secondary cell wall remained colourless. The anatomical structure of the cell wall residue after 192 h in vitro digestion was similar to that of the positively stained part of the delignified cell walls. Pyrolysis mass spectrometry of the sections after delignification showed that virtually all mass information of lignin compounds and part of the sugar polymers had disappeared. Permanganate oxidation removes carbohydrates and phenolics from in situ degradable cell walls.

Analytical pyrolysis mass spectrometry (PYMS) is introduced and its applications to the analysis of synthetic polymers, biopolymers, biomacromolecular systems and geomacromolecules are critically reviewed. Analytical pyrolysis inside the ionisation chamber of a mass spectrometer, i.e. in-source PYMS, gives a complete inventory of the pyrolysis products evolved from a solid sample. The temperature-resolved nature of the experiment gives a good insight into the temperature dependence of the volatilisation and pyrolytic dissociation processes. Chemical ionisation techniques appear to be especially suitable for the analysis of oligomeric fragments released in early stages of the pyrolysis of polymer systems. Large oligomeric fragments were observed for linear polymers such as cellulose (pentadecamer), polyhydroxyoctanoic acid (tridecamer) and polyhydroxybutyric acid (heneicosamer). New in-source PYMS data are presented on artists' paints, the plant polysaccharides cellulose and xyloglucan, several microbial polyhydroxyalkanoates, wood and enzyme-digested wood, biodegraded roots and a fossil cuticle of Miocene age. On-line and off-line pyrolysis chromatography mass spectrometric approaches are also discussed. New data presented on high temperature gas chromatography—mass spectrometry of deuterio-reduced permethylated pyrolysates of cellulose lead to a better understanding of polysaccharide dissociation mechanisms. Pyrolysis as an on-line sample pretreatment method for organic macromolecules in combination with MS techniques is a very challenging field of mass spectrometry. Pyrolytic dissociation and desorption is not at all a chaotic process but proceeds according to very specific mechanisms.

Phenolic acids in complex biological matrices are easily decarboxylated under pyrolysis electron impact (EI) conditions depending on their binding to other plant cell wall compounds. Pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) of phenolic acids reveals only the decarboxylated compound but this product may also be derived from the alcoholic lignin monomers. Discrimination between the acidic and alcoholic phenol can be obtained by stabilization of the molecular ion of the two compounds. Samples of p-coumaric acid, of sporopollenin from Pinus pollen wings, of bamboo milled wood lignin (MWL) and of tobacco leaf nerve MWL were analysed by analytical Py-EIMS. Mass peaks for the molecular ion of p-coumaric acid and of the decarboxylated product may be observed. Results are compared with Py-MS data of samples treated with tetramethylammonium hydroxide (TMAH), a compound used to methylate the phenolic hydroxyl group and the carboxyl group of the phenolic acid in the ion source of the mass spectrometer. Mass spectra of samples treated with this agent show a high content of double methylated p-coumaric acid (m/z 192). TMAH treatment allows discrimination between phenolic acids and alcohols under Py-MS and Py-GC/MS conditions by producing more stable molecular ions.

It has been suggested that marine humic and fulvic acids are formed by a condensation of sugars with amino acids or proteins via Maillard reaction. In order to investigate this hypothesis a series of melanoidins were synthesised under laboratory conditions and their structure compared with natural humic acids. An extensive collaborative research programme on the chemical and physical properties of natural and synthetic humic substances has been undertaken using spectroscopic (IR, UV, 13C-CP/MAS NMR, ESR), chromatographic (GC and GC/MS), thermogravimetric (TG, DTG, TG-EGD-MS), pyrolytic (stepwise, Rock Eval, Curie point) oxidative (KMnO4) and isotopic methods. The results indicate that various heterocyclic moieties are the main building blocks of humic substances rather than aromatic benzenoid structures. It seems possible that significant portions of humics of Lake Haruna (Japan) as well as of Lake Hula (Israel) are composed of melanoidins and/or pseudomelanoidins. The extent of this contribution has not yet been determined.

This study describes the analysis of sulphur-containing products from Curie-point pyrolysis (Py) of eighty-five samples (kerogens, bitumen, and petroleum asphaltenes and coals) using gas chromatography (GC) in combination with sulphur-selective detection. Peak areas of approximately forty individual organic sulphur pyrolysis products (OSPP) were measured, and the results analysed with the aid of multivariate data reduction techniques (principal components analysis, (PCA)). The structural relationships proposed in an earlier publication ( Sinninghe Damste et al., 1989a) in which OSPP can be grouped according to common “carbon skeletons” are supported by PCA. The distribution of OSPP varies both as a function of kerogen type (as defined by elemental composition) and maturity, reflecting differences in the relative abundance of the various carbon skeleton types. Sulphur-containing products from Type I, Type II, and, to some extent, Type II-S kerogens are dominated by OSPP derived from “moieties” (i.e., discrete structural components within the macromolecule) possessing linear carbon skeletons, while coals and Type III kerogens give rise to higher relative abundances of OSPP with branched carbon skeletons. Type I kerogens are distinguished from Type II kerogens due to the type of linear carbon skeleton, the former yielding higher relative amounts of 2-n-alkylthiophenes and thiolanes and the latter 2,5-di-substituted sulphur-containing products. Products from sulphur-rich (Type II-S) kerogens differ by higher relative abundances of OSPP derived from precursors with isoprenoid and/or steroidal side-chain carbon skeletons, and by higher absolute abundances of all OSPP. Petroleum and, to a lesser extent, bitumen asphaltenes give rise to OSPP with longer carbon skeletons than do kerogens or coals. This observation supports the models proposed by Sinninghe Damste et al. (1990a) in which sulphur-containing moieties in asphaltenes are bound by fewer intermolecular bridges (i.e., are less extensively cross-linked) and, consequently, more readily yield longer chain products on pyrolysis. From these observations, we suggest that Py-GC in combination with PCA provides useful information concerning the chemical nature of organically bound sulphur in geomacromolecules. This information can be rationalised based on carbon skeleton relationships established for low molecular weight organic sulphur compounds, and in terms of kerogen type and overall sulphur content

Two milled wood lignins (MWLs) were isolated from tobacco leaves (laminae) and midrib material according to the Bjorkman procedure. Prior to MWL isolation, the material was extracted with cyclohexane/ethanol and hot water to remove extractives which could interfere with this isolation. MWLs were obtained with a yield of 0.03% (leaves) and 0.06% (midribs) based on dry pre-extracted material. FT-IR spectroscopy was used for quality control and classification of the isolates. Both preparations fulfilled the spectroscopic lignin criteria of a GS lignin with low syringyl content, although the isolates were not pure. Besides carbohydrate impurities, the lamina material, especially, was contaminated with nitrogen and fatty acid-containing substances. Proteins and cutin are discussed as probable contaminants. Both MWLs were characterized with quantitative pyrolysis—gas chromatography using a resistant heating instrument. Curie-point pyrolysis—gas chromatography/mass spectrometry and pyrolysis—mass spectrometry were used for additional characterization of yboth MWL samples. The results show that the tobacco MWL contains up to 22% carbohydrate-type impurities. Small amounts of alkaloids, proteins and lipids were also detected as contamination. Results of previous studies on mineral acid residues could be corroborated: tobacco lignin contains approximately 10% 4-hydroxyphenylpropane, 78–82% guaiacylpropane and 10–13% syringylpropane moieties.

Synchrotron based X-ray microtomography is a novel way to examine paint samples. The three dimensional distribution of pigment particles, binding media and their deterioration products as well as other features such as voids, are made visible in their original context through a computing environment without the need of physical sectioning. This avoids manipulation related artefacts. Experiments on paint chips (approximately 500 micron wide) were done on the TOMCAT beam line (TOmographic Microscopy and Coherent rAdiology experimenTs) at the Paul Scherrer Institute in Villigen, CH, using an x-ray energy of up to 40 keV. The x-ray absorption images are obtained at a resolution of 350 nm. The 3D dataset was analysed using the commercial 3D imaging software Avizo 5.1. Through this process, virtual sections of the paint sample can be obtained in any orientation. One of the topics currently under research are the ground layers of paintings by Cuno Amiet (1868- 1961), one of the most important Swiss painters of classical modernism, whose early work is currently the focus of research at the Swiss Institute for Art Research (SIK-ISEA). This technique gives access to information such as sample surface morphology, porosity, particle size distribution and even particle identification. In the case of calcium carbonate grounds for example, features like microfossils present in natural chalks, can be reconstructed and their species identified, thus potentially providing information towards the mineral origin. One further elegant feature of this technique is that a target section can be selected within the 3D data set, before exposing it to obtain chemical data. Virtual sections can then be compared with cross sections of the same samples made in the traditional way.

The performance of a newly developed photoionization source in combination with a high resolution mass spectrometer is tested. The total ion currents for several linear alkanes ( n -pentane to n -decane) and for some thiophenes (2-methylthiophene, 2,5-dimethylthiophene and 2-ethylthiophene) are measured at three fixed wavelengths: the Kr I (10.03 eV and 10.64 eV), Ar I (11.62 eV and 11.83 eV) and Ne I (16.67 eV and 16.85 eV) resonance lines. These total ion currents are compared with the data for the alkanes and thiophenes obtained with low energy (10.6 eV, 11.8 eV and 16.7eV) electron impact ionization on the same mass spectrometer. The loss in ion intensity at several positions throughout this instrument is determined for the photo-ionization source and for the electron impact ionization source. One out of every 1500 ions created in the photoionization source is measured by the detector. For the electron impact ionization source, one out of 180 ions is measured. The introduction of a five-element “Heddle” lens for the transfer of the ions from the photoion source to the mass analyser resulted in an approximately 1.5 fold loss in ion current. From the measured total ion intensities, the photoionization and electron impact ionization cross-sections at energies of 10.6 eV, 11.8 eV and 16.7 eV are calculated. The photoionization cross-section values of the linear alkanes are found to be in the range of 2.5 Mbarn to 355 Mbarn, and the electron impact ionization cross-section values are between 40 Mbarn and 735 Mbarn. The photoionization cross-section values of the thiophenes range from 4 Mbarn to 31 Mbarn, and the electron impact ionization cross-section values from 81 Mbarn to 760 Mbarn.

Introduction Pyrolysis has many similarities to the fragmentation processes used in mass spectrometry: in both large molecules are broken down into smaller pieces, more amenable to clear identification, by the transfer of sufficient energy to the target molecule to break chemical bonds. In pyrolysis this energy is in the form of heat whereas in mass spectrometry (m.s.) a wide range of ionization mechanisms are used which give very different levels and distributions of energy deposition, and thus allow some control of fragmentation. A major difference is that pyrolysis works on the original material while mass fragmentography usually utilizes a previously ionized precursor. The line between the two techniques becomes blurred when the m.s. ionization procedure could easily be seen as a form of pyrolysis, as is the case with direct chemical ionization (DCI) under many conditions and with laser desorption ionization (LDI). Pyrolytic processes are important factors in combustion: by supplying flammable volatile compounds some distance from the initial site they help to spread the fire and contribute a substantial proportion of the energy output. This is particularly true of polysaccharide-based materials which produce large amounts of flammable gas on heating (pyrolysis). Polysaccharide-based materials are dominating features of our built environment. Wood is a major component of our buildings and

The combination of laser desorption followed by multiphoton ionization (MPI) with time of flight mass spectrometry (TOF/MS) produces a versatile method of high sensitivity and selectivity. The first step is laser desorption in which molecules are desorbed from the sample intact or with little degradation. Laser ionization is employed as the second step to produce the ions and also induce fragmentation. Soft ionization, which yields primarily the parent ion, and hard ionization, which yields primarily the fragments, are both possible. Instrumental details are described and preliminary results from recent laser desorption MPI-TOF/MS experiments on a perbenzoylated sugar and on a porphyrin are presented. Examples from single photon ionization (SPI) experiments on two alkanes are also shown.

The addition of synthetic polymer standards to geological samples in order to provide quantitative data on pyrolysis product yields of the latter has been shown to be a valuable tool in pyrolysis-gas chromatography (Py-GC). The applicability of this approach for pyrolysis-mass spectrometry (Py-MS) is the focus of the present study. In general, good agreement was found in comparisons of yields of different compound classes determined by Py-MS with data from Py-GC and elemental analysis. Whilst no response factors were determined semi-quantitative data could readily be obtained for the compounds of interest. Examples are given of how different kerogen types can be distinguished not only on the basis of the relative abundance of different compounds, but also their yields. A practical example of the utility of this approach is provided in a study of compositional variations in petroleum asphaltenes. Here, differences were observed not only between petroleum asphaltenes generated from different source rocks, but also within a single oil reservoir (Ula Field, Norwegian North Sea). Whilst Py-MS suffers from several limitations (lack of information on carbon number distribution, compound-specific response factors, multiple contributions to nominal masses) the method has the advantage over Py-GC of being more rapid and providing data in a more readily analysable form. An example of the manner in which to overcome the problem of multiple contribution to nominal masses is shown through the application of higher resolution mass spectrometry.

The suitability of analytical pyrolysis techniques for the chemical characterisation of amorphous (charred) organic residues obtained from prehistoric pottery was studied. No chemical preparation of the sample was needed and the analysis was performed on very small samples (20–30 μg). Curie-point pyrolysis mass spectrometry and Curie-point pyrolysis gas chromatography were used for rapid characterisation of 33 residue-samples obtained from the outside (5) and inside (28) of different types of pottery from the native Roman settlement at Uitgeest-Groot Dorregeest (Netherlands). Discriminant analysis of the data shows several groups of residues of different chemical composition. Four representative residue samples were selected for more detailed analysis by Curie-point pyrolysis—gas chromatography/mass spectrometry. Many bio-organic moieties were detected in the residues situated on the inside of pots including fatty acids and characteristic markers for proteins and polysaccharides. Since no indications could be found to assume severe post-depositional changes in chemical composition, it is clear that the composition of the residues is a reflection of the original use in prehistoric times. The refractory nature of the charred (food) residues causes the preservation of the bio-organic characteristics. Other classes of compounds, such as polycyclic aromatic hydrocarbons, were detected in residues from the outside and were interpreted as smoke condensates from open cooking fires. A regular alkane/alkene pattern found in many residues and in the ceramic material of the pot sherd is interpreted as the pyrolysis product of an aliphatic network that has been formed from foodstuffs under high temperature conditions during cooking.

The condensate from Curie-point pyrolysis of cellulose has been examined as the permethylated derivative and as the borodeuteride-reduced permethylated derivative. The main complete sugar peaks were identified as levoglucosan and cellobiosan. Fragments were also identified which were derived from reverse aldolisation cleavage of a sugar ring to leave acetaldehyde fragments on the reducing and non-reducing ends of intact sugar units. No peaks of significant intensity could be identified as anhydrosugar units with attached ring cleavage fragments.

Macromolecular chlorolignins and lignosulphonates have been analysed in effluents from five pulp mills discharging on the river Rhine. Analytical techniques used were ultrafiltration, pyrolysis—mass spectrometry and pyrolysis—gas chromatography / mass spectrometry. The average organically bound chlorine content was 19 mg/l, with a maximum value of 68 mg/l for the pulp mill Cellulose de Strasburg. The annual discharge of organically bound chlorine (AOX) and of dissolved organic carbon (DOC) of these five mills was calculated to be 2100 tonnes AOX and 33 000 tonnes DOC, respectively. This would account for 90% of the AOX load and 10% of the DOC load of the river Rhine. Evidence for the existence of two chlorolignin classes, aromatic chlorolignins and aliphatic chlorolignins, was obtained. Monochloroguaiacol is the most abundant structural specific aromatic chlorolignin pyrolysis product. Methyl chloride is a major chlorine containing pyrolysis product, probably originating from aliphatic chlorolignins. Sulphur dioxide is a major pyrolysis product of lignosulphonates, and possibly can be used for the specific quantitative determination of lignosulphonates in river water. Radical recombination reactions of methyl radicals and other primary pyrolysis radicals play an important role in these samples, leading to several secondary pyrolysis products. The presence of lignosulphonates in the salt or acid form has an important effect on the pyrolysis process. Methyl chloride can probably be quantified with the reference compound tetramethylammonium chloride. The macromolecular compositions of these effluents show many similarities, but also significant differences, presumably reflecting the use of different wood types, pulping and bleaching conditions at the time of sampling.

The decay of Eucryphia cordifolia wood by white-rot and brown-rot fungi was studied with pyrolysis electron impact mass spectrometry (Py(EI)MS) and pyrolysis ammonia chemical ionization mass spectrometry (Py(CI)MS). Py(EI)MS spectra of the wood after decay by the white-rot fungus Ganoderma australe no longer show mass peaks indicative for lignin. The relative abundance of syringyl (dimethoxy) compounds decreases faster than the coniferyl (monomethoxy) compounds. In the same spectra the relative abundance of hexosans increases whereas the relative amount of pentosans remains constant. The presence of oligomeric sugars in the Py(CI)MS spectrum points to a preservation of some polysaccharides. Brown-rot fungal degradation of similar wood samples analysed with Py(EI)MS reveals no mass peaks for polysaccharides, resulting in a spectrum with mass peaks specific for lignin. The Py(EI)MS, revealing lignin dimers, and the Py(CI)MS spectra suggest that the lignin was not modified by the brown-rot fungus. However, the pyrolysis gas chromatography mass spectrometry (PyGCMS) data show an increase in oxygenated lignin pyrolysis products suggesting a molecular change in the lignin due to brown-rotting. In the brown-rotted wood one sugar pyrolysis product (levoglucosan) was observed by Py(CI)MS and PyGCMS suggesting that part of the cellulose polymer system is inaccessible to fungal degradation. Comparing data obtained from 13C cross polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR) with data obtained from PyMS reveals that the latter method provides much more structural information.

An isolation procedure is presented for enrichment of lignin in lamina and midrib of tobacco by digestion with the enzymes pronase (protease) and cellulase (polysaccharidase). Digestion by cellulase was successful only after mechanical fracturing of the wall matrix, extensive removal of cytosolic and extraneous wall components, and after the chemical disclosure of the wall by pronase digestion. The purity of the enzyme digested residues and controls was checked by pyrolysis—mass spectrometry (Py-MS) and Curie-point pyrolysis—gas chromatography / mass spectrometry (CuPy-GC/MS). CuPy-GC/MS showed exclusively markers for lignin and carbohydrates in the pyrolysates of the enzyme digested tobacco samples. Lignin was clearly enriched in the enzyme digested residues. The relative distribution of monomeric and dimeric lignin pyrolysis products in the pyrolysis-mass spectra was comparable in lamina and midrib material. The lignin in both tobacco lamina and midrib material can be classified as a GS lignin with low amounts of coumaryl and syringyl units. Substantial amounts of carbohydrates were shown to be remaining in the residues. Cellulase digestion resulted in a reduction of 60% of the hexose markers in the pyrolysate of the lamina material and of 40% in the midrib material. The MS data on the lignin in enzyme digested cell walls of tobacco lamina material were compared with those from the Bjorkman lignin of the same tobacco sample. The Bjorkman tobacco lignin was a highly purified soluble lignin isolate contaminated with minor amounts of carbohydrates. CuPy-GC/MS indicated a higher abundance of syringyl units in the Bjorkman lignin compared to enzyme digested residues of the lamina material. This difference is presumably caused by a selective (Bjorkman) extraction of lignin from the secondary cell wall. The enzyme prepared lignin not only uses a milder preparation method but also gives a more complete view into the cell wall lignin of tobacco.

The thermal stability and the thermal degradation products of high impact polystyrene / decabromodiphenylether / antimony oxide (HIPS FR) have been studied in situ with derivative thermogravimetry (DTG), temperature resolved pyrolysis—mass spectrometry (Py-MS) and pyrolysis—gas chromatography / mass spectrometry (Py-GC /MS). With in-source temperature resolved Py-MS (negative ions) the thermal degradation processes of HIPS FR have been studied dynamically and antimony (oxy)bromides and brominated higher styrene oligomers upto n = 15 have been detected. During degradation of the HIPS FR polymer matrix several processes take place, such as debromination of the flame retardant decabromodiphenylether to form less brominated diphenylethers, bromination of polystyrene and formation of antimony bromides and antimony oxybromides. The formation of toxic polybrominated dibenzofurans (PBDFs) has been shown to occur in the temperature range in which the HIPS FR polymer matrix degrades (350–400°C). This is explained by debromination of decabromodiphenylether to form less brominated diphenylethers which are much more reactive towards formation of PBDFs.

Minute samples of xylem from healthy and Fusarium oxysporum f.sp. dianthi -infected stems of carnation cultivars differing in degree of resistance to F. oxysporum were investigated by in-source pyrolysis low voltage EI mass spectrometry and by pyrolysis under ammonia CI conditions. Healthy xylem of both cultivars showed PY-MS spectra with markers for cellulose, hemicelluloses, phenolic acids, and a mixed guaiacyl-syringyl lignin. At different stages of infection visibly infected, brown coloured, xylem was separated under the microscope from healthy-looking parts. The PY-MS spectra of the diseased xylem of susceptible ‘Lena’ were entirely different from those of healthy(-looking) areas, showing a drastic change in lignin pyrolysis product distributions. In most cases practically all syringyl constituents, both mono- and dimeric, had disappeared. In some cases also an overall decrease in relative intensity of the lignin pyrolysis products was observed. Invasion of the fungus thus induced a major change of cell wall composition as a result of lignin degradation along different pathways: demethoxylation of syringyl units, the major pathway in ‘Lena’, and propenyl side chain oxidation. The PY-MS spectra of infected ‘Novada’ generally showed the overall oxidation of lignin and less demethoxylation. The ‘Novada’ spectrum also showed m/z 239, 287, and an increase of 257 and 271, which are molecular ions indicative of the phytoalexins dianthalexin and the dianthramides methoxydianthramide S, hydroxydianthramide B and methoxydianthramide B. The compounds appeared comparatively volatile and therefore could be desorbed as a thermal extract before other pyrolysis fragments appear. The compounds were practically absent in adjacent, healthy looking, xylem. Low voltage EI MS of methanol extracts of about 2 mm 3 of infected ‘Novada’ xylem confirmed these data and in a single case also showed evidence for hydroxyanthranilic acid ( m/z 153) which is attributed to degradation of dianthramine. Spectra of thermal and methanolic extracts were quite similar.

The relative distribution of phytoalexins induced by Fusarium oxysporum fsp. dianthi in carnation and localized by pyrolysis-mass spectrometry in the xylem differs from that found by HPLC in acetone extracts. In situ , in the xylem, there is a predominance of 2-aryl-1,3-benzoxazin-4 H -ones over the more fungitoxic N -aroylanthranilates. At least part of the dianthramides in the extracts has to be ascribed to artifacts apparently due to hydrolysis of benzoxazinones.

Cell walls from coastal Bermudagrass (Cynodon dactylon (L.) Pers.) (CBG) and ‘Kentucky-31’ tall fescue (Festuca arundinacea Schreb.) (K-31) were treated with ozone and the resulting residue with sodium hydroxide. The aromatics and polysaccharides of the treated cell walls and the residues from ozone and ozone/base treatments were studied by pyrolysis mass spectrometry. Ozone effectively removed lignin from the cell walls of both grass species. The residue from ozone-treated CBG cell walls showed mass markers characteristic of condensed lignin whereas the base-treated residue from ozone-treated K-31 cell walls showed no lignin remaining in the sample and principally polysaccharides being left. This difference may be due to the type of lignin present in the two grasses which, in turn, may relate to CBG cell walls being less digestible by rumen microorganisms.

During micro-pyrolysis of polybrominated diphenylethers (PBDPOs), which are used as flame retardants in synthetic polymer blends, PBDDs and PBDFs are formed. The yield decreases from Br 5 DPO→Br 8 DPO→Br 10 DPO due to the energetically favourable elimination of HBr. The influence of the high impact polystyrene (HIPS) polymer matrix on the formation consists of a selectivity towards formation of PBDFs, a shift in the optimal PBDF formation temperature from T =600°C to the HIPS depolymerisation temperature T=350–400°C and an enhancement of the total yield of PBDFs with a factor 7. The key towards understanding of the low PBDF formation temperature lies in the fact that PBDPOs are incorporated in a polymer matrix. During radical depolymerisation of the HIPS polymer matrix PBDFs are formed by the exchange of hydrogen and bromine which is followed by a ring closure reaction. The thermal degradation processes of HIPS Br 10 DPO Sb 2 O 3 were studied dynamically with in-source temperature resolved Py-MS (negative ions). Several processes taking place during degradation of the HIPS Br 10 DPO Sb 2 O 3 polymer matrix, like debromination of the flame retardant Br 10 DPO to form less brominated diphenylethers, formation of PBDFs, bromination of polystyrene and formation of antimony (oxy)bromides, were elucidated with this technique.

The responses of four carnation cultivars to infection with races 1 or 2 of Fusarium oxysporum f.sp. dianthi and with Phialophora cinerescens were investigated. Four and nine days after stem inoculation with the different wilt pathogens, 5 cm stem segments were extracted and analysed for the accumulation of dianthalexins and dianthramides by HPLC, and approximately 1 mm3 blocks of xylem tissue were sampled and analysed by pyrolysis-mass spectrometry. Analysis of wilt development over a two-month period confirmed the differential responses of the cultivars to the pathogen isolates. The level of accumulation of the dianthramides was determined partly by the cultivar and partly by the invading pathogen and was not related to the level of symptoms developed. P. cinerescens induced the highest dianthramide concentrations, followed by F. oxysporum f.sp. dianthi, race 2. Race 1 elicited slight dianthramide accumulation and was less inhibited by them in vitro than was P. cinerescens. Pyrolysis-mass spectrometry indicated lignin degradation by all fungi and confirmed, in increasing order, induction of dianthramide phytoalexin accumulation in plants infected with F. oxysporum f.sp. dianthi race 1, race 2 and P. cinerescens. Irrespective of the pathogen, each inoculated cultivar showed a unique pattern of demethylation and degradation of pectin, degradation of lignin and hemicellulose, and changes in polysaccharide-bound phenolic acids.

The organic matter present in coarse- and fine-grained sample preparations of a peat core from Minnie's Lake, Okefenokee Swamp (Georgia, USA) was analysed on a molecular level by gas chromatography-mass spectrometry of alditol acetates obtained from polysaccharides after acid hydrolysis and derivatization and by flash pyrolysis-mass spectrometry. We found that the coarse-grained fraction is dominated by neutral monosaccharides derived from vascular plants whilst the fine-grained fraction is dominated by neutral monosaccharides derived from microorganisms. Relatively high contributions of xylose discriminate the Taxodium derived peat from the underlying peats derived from Carex and Nymphaea which show relatively low contributions of this sugar. Factor-discriminant analysis of the Py-MS data indicates that most carbohydrate degradation is restricted to the upper peat levels and that guaiacyl and syringyl type lignins are better preserved than carbohydrates. Resinous organic matter - presumably derived from Taxodium — is selectively preserved in the fine-grained fraction. Deviant monosaccharide concentrations and Py-MS results observed for the top sample of the Carex peat were explained by oxygenation of the peat, a concomitantly high microbial activity and subsequent preservation of the organic material due to the action of phytotoxins derived from Taxodium.

Acid hydrolysates of fractionated red mangrove peat samples and handpicked roots and rootlets of Rhizophora mangle (red mangrove) from Jewfish Key in the Florida Everglades were analysed for neutral monosaccharides. In the peat samples two major sources of carbohydrates could be determined: 1. (1) vascular plant carbohydrates derived from Rhizophora mangle and 2. (2) microbially derived carbohydrates. Significant correlations exist between the relative contributions of most neutral monosaccharides and the total carbohydrate concentration. The fine-grained peat fractions yielded low total neutral monosaccharides whose distributions indicate contributions of microbial carbohydrates. The coarse-grained peat samples yielded high total neutral monosaccharides with distributions indicating major contributions of vascular plant carbohydrates. It is estimated that a substantial part of the sugars analysed in the finegrained samples originates from microorganisms ([cyano] bacteria, algae).The absence of a trend in total neutral monosaccharide concentrations with depth suggests that microbial degradation is limited to the upper levels of the peat and that the microbial sugars determined at lower peat levels are derived from nonviable or dormant microorganisms. Results from factor analysis may suggest differences in microbial populations in the various peat samples.

Small pieces of different tissues from stems of young and old carnation plants were analyzed for lignification (lignin/cellulose ratios) and lignin composition by means of pyrolysis-(gas chromatography)-mass spectrometry. The epidermis and phloem of young and old stems were essentially non-lignified. Pith parenchyma was only lignified in mature and senescing tissues. The type of lignin in sclerenchyma differed from that in xylem and pith. Lignification in the xylem of very young tissues was a mainly guaiacyl-type lignin, which gradually changed into a mixed guaiacyl-syringyl lignin in older tissues. In mature tissues, the sclerenchyma was more highly lignified than the xylem.All tissues yielded comparatively large amounts of dihydroferulic acid, a compound which may be specific for carnation.

A study was made of decomposition ofCeratophyllum demersum litter over a 17-day period under controlled conditions of temperature and oxygen (5, 10 and 18 °C; aerobic and anaerobic) and over a 169-day period in the field (Lake Vechten, The Netherlands). Litter, water and sediment were sampled on the 0, 2, 4, 7 and 17th day under controlled conditions and on the 0, 17, 49, 127 and 169th day in the field. The litter was analyzed quantitatively for dry mass, ash, carbon, nitrogen, phosphorus and qualitatively of organic composition by pyrolysis mass spectrometry. The water was analyzed for the elemental concentrations of organic carbon (total and dissolved), nitrogen (total, ammonia and particulate) and phosphorus (total and orthophosphate) and for the concentrations of photosynthetic pigments and bacteria. The sediment was analyzed for the elemental concentrations of nitrogen, carbon and phosphorus, and for bacterial numbers. The pattern of litter mass loss fitted an exponential model fairly well. Mass decreased faster under controlled aerobic than under anaerobic conditions and the decrease was stimulated by increasing temperature, relatively more in the range of 5 to 10 °C (by 20%) than in the range of 10 of 18 °C (by 2%). The residual mass ranged from 73 to 43% of initial under controlled aerobic conditions and from 84 to 65% under anaerobic conditions after 17 days. It decreased far less in the field, to 38% of initial mass in the field after 169 days. The litter initially lost a carbohydrate fraction by leaching in all treatments. The protein content decreased initially as well but increased subsequently at increasing temperature stimulated under anaerobic conditions. The changes in organic composition were correlated with those in nitrogen but not with those in carbon and phosphorus contents. The organic composition of litter incubated in the field differed from that of litter incubated in the laboratory. The field residues contained less proteinaceous material than the laboratory residues. The changes in carbon, nitrogen and phosphorus concentrations in the litter showed different patterns. The carbon concentration generally increased, the nitrogen concentration initially dropped and increased subsequently, and the phosphorus concentration initially dropped and remained relatively constant subsequently. Chemical immobilization of the decomposition process may have occurred in the laboratory, but was unlikely in the field. Carbon, nitrogen and phosphorus left the litter initially largely in particulate form and were recovered in the water. The ratio dissolved: total nutrient concentration was lower under controlled aerobic than under anaerobic conditions. Increasing temperature stimulated bacterial use of dissolved organic carbon and nitrogen. A rapid nutrient flow occurred from macrophyte litter, via water to sediment. The phytoplankton biomass in the water was greatly stimulated by substances freed from the decomposing litter. Diatoms increased generally relatively more than green algae, predominating alternatively with green algae under aerobic conditions and continuously under anaerobic conditions. Bacterial numbers in the water initially increased, partly due to transgression of bacteria from the sediment-water interface to the water and partly due to an actual increase in community biomass. The bacteria returned largely to the sediment-water interface, stimulated by increasing temperature, as most of the substrate readily usable by them had left the litter in the litter-bag and was associated with the upper sediment layers. It is feasible that the annual die-off of theC. demersum population of Lake Vechten barely affects nutrient cycling in the lake, because the contribution to the nutrient pools of the lake when fully mixed is only small. However, small particles originating from decomposingC. demersum litter may influence the lake considerably by decreasing water transparency and serving as a food source for filter-feeders and detritivorous macrofauna.

Beech wood samples (stem, root and biodegraded wood) as well as beech milled wood lignin, beech polysaccharide fractions (holocellulose, xylan and technical xylan) and microcrystalline cellulose were analysed by pyrolysis-mass spectrometry (Py-MS), i.e. Curie-point pyrolysis low voltage electron impact (EI) MS, as well as by in-ion source platinum filament pyrolysis MS under both ammonia chemical ionisation (CI) and low voltage EI conditions. The mass spectra reveal the presence of monomeric, submonomeric as well as di- and oligomeric pyrolysis products from polysaccharides and/or lignin. The difference in pyrolytic behavior of polysaccharides in the complex wood matrix and of the purified polysaccharides may find its cause in chemical and physical interactions between polysaccharides and lignins in the wood, or may be due to the presence of considerable amounts of inorganic cations in the sample. The pyrolytic behavior of lignin is not significantly influenced by the presence of inorganic cations. The holocellulose and xylan data also exhibit chlorinated lignin marker compounds, which point to the presence of partly chlorinated lignin in the sample. This is probably an artefact due to the isolation procedure of these fractions, which involves treatment with sodium hypochlorite solution. The CI data of the technical xylan fraction indicate the presence of di- and oligomeric pentoses, hexoses and pentose/hexose sugars. These are probably formed during the isolation procedure (which involves extraction of wood chips at 170°C) by partial depolymerisation of the polysaccharide moiety.

Investigations on the effluent of a German pulp mill on the river Rhine using ultrafiltration and pyrolysis gas chromatography mass spectrometry have shown the presence of several chlorinated 2-methoxyphenols, which probably originate from chlorinated lignin or lignosulfic acid. Chlorinated phenolic pyrolysis products identified were 2-methoxy-6-chlorophenol, 2-methoxy-4-methyl-6-chlorophenol, 2-methoxy-dichlorophenol, 2-methoxy-4-vinyl-6-chlorophenol, 2-methoxy-4-(chloropropyl)phenol, 2-methoxy-4-(prop-2-enyl)-6-chlorophenol, 2-methoxy-4-(propan-2-one)-6-chlorophenol, 2-methoxy-3, 5, 6-trichlorophenol, 2-methoxy-4-vinyl-3, 5, 6-trichlorophenol. Monochlorinated 2-methoxyphenols were the dominant chlorinated pyrolysis products, smaller amounts of di- and trichloromethoxyphenols were also detected. 2-Methoxyphenols (guaiacols) were the dominant lignin pyrolysis products, only small amounts of 2, 6-dimethoxyphenols (syringols) were detected. This indicates the origin from soft wood. A Py-(GC)-(MS)-T...

The depth-profiles of accelerated aged triterpenoid dammar and mastic varnishes, which had been uncovered by optimized KrF excimer laser ablation (248 nm, 25 ns), were examined by ultraviolet–visible (UV/VIS) spectrophotometry and attenuated total reflection (ATR) Fourier transform infrared (FT-IR) spectroscopy. The results reflect both the optical properties at the bulk (UV/VIS) and the surface (ATR/FT-IR) and establish the presence of degradation gradients across the depth of the degraded natural resin films. It is demonstrated that the UV part of the ambient radiation is absorbed by the deteriorated surface and that the optical densities of the aged varnish decrease as a function of depth. The absorbed UV wavelengths at the surface and the depth-wise reduction of light intensity result in a depth-dependent decrease in carbonyl absorbance and an increase in C–H bending vibration modes of methylene species pointing to structural modification in the triterpenoid mixture across depth.

This paper discusses findings that establish the ageing-induced compositional and crosslinking gradients across the depth-profiles of two accelerated aged natural resin varnishes: dammar and mastic, which are commonly applied to paintings. Profile measurements of laser-processed films using a KrF excimer laser, as well as online measurements of the C2 emission by laser-induced breakdown spectroscopy (LIBS), showed a significant reduction of the ablation step and ablation yield with depth, respectively. Direct temperature mass spectrometry (DTMS) showed that the oxidation products formed upon ageing were gradually eliminated across depth, which affected the depth-wise optical properties of the films studied by UV/VIS spectrophotometry. The total ion currents of the DTMS in the electron ionisation mode (EI, 16 eV) demonstrated also a gradual reduction of the pyrolysis yield which corresponded to a gradual depth-wise elimination of the high MW fractions that was confirmed by size exclusion chromatography (SEC). The gradients were established also by surface analyses, such as matrix-assisted laser desorption/ionisation-time-offlight-MS (MALDI-TOF-MS) and attenuated total reflection-Fourier transformed infrared spectroscopy (ATR-FTIR), which indicated that the action of the KrF excimer laser is non-destructive to the varnish when optimal fluences are used for the laser cleaning process. The extracted data enabled the quantification of the compositional gradients and unraveled a significant feature of natural resins, which would not have been possible without the use of KrF excimer lasers.

Hierarchical structures appear often in life and materials sciences, and their characterization profits greatly from imaging methods that allow seamless probing of various length scales without sacrificing image quality. X-ray tomography is particularly adept at probing 3D structures; however, zooming in on a region of interest results in a loss of quantitativeness of image contrast and suffers from artifacts unless a priori knowledge or assumptions about the sample are used. Here, we demonstrate a hybrid technique that exploits a micrometer-resolution overview to realize ab initio nanoscale interior tomography with quantitative contrast. In a study of avian eggshell, a model for bionanoporous materials, our approach reveals a complex arrangement of vesicles with sizes ranging from hundred nanometers to a few micrometers. We anticipate that such an approach can be widely adopted and benefited from at synchrotron and laboratory sources, for instance, where such zooming capabilities are already present or can be readily realized.

KrF excimer laser ablation of two artificially aged triterpenoid films was studied. Ablation rate variations across film thicknesses implied compositional change with depth. Deviations between calculated and measured depths-steps at deeper ablated layers verified previously determined gradients. The findings were confirmed with DTMS, which demonstrated that excimer laser ablation with optimum fluences does not induce oxidation.

Different oil processing methods were performed, which included washing with water and treatment with lead-based driers, with and without heating to different temperatures, giving a set of 7 oils to be investigated. The effects of the traditional processing methods of linseed oil on its triacylglycerol (TAG) composition were studied, using the following analytical methods: high performance size exclusion chromatography (HPSEC), Fourier transform infrared spectroscopy (FTIR), high-performance liquid chromatography-atmospheric pressure chemical ionisation-mass spectrometry (HPLC-APCI-MS), direct temperature resolved mass spectrometry (DTMS), matrix assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS), and electrospray ionisation Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS). A decrease of the initial cis-double bonds and the formation of trans-double bonds upon heating of the oils was observed. Heating a lead and oil mixture to 150 degrees C, or heating the oil alone to 300 degrees C led to the highest degree of oxidation. A difference was observed for the oxidation patterns for oils with and without the addition of lead. Furthermore, levels of oxygen incorporation were higher when lead was added to the oil. High temperature treatment of the oils resulted in an increased average molecular weight. The changes in the initial conformation of the double bond systems observed with FTIR were supported by HPLC-APCI-MS measurements that showed the formation of a number of new isomeric TAGs in the heated oil compared to freshly pressed, untreated oil. Oligomerisation up to hexamers was observed with HPSEC, and MALDI-TOF-MS. The formation of oligomers up to trimers only, however, was observed with ESI-FTICR-MS. Incorporation of oxygen was mainly observed with MALDI-TOF-MS and ESI-FTICR-MS whereas with DTMS and FTIR hardly any evidence was found for this.

Static secondary ion mass spectrometry (SIMS) is introduced as an analytical technique for the examination of paint cross sections to obtain simultaneous information about the nature and distribution of pigments and the binding medium from a single sample. A sample taken from the virgin's blue robe in the panel painting The Descent from the Cross (Museo del Prado, Madrid) of the Early Netherlandish painter Rogier van der Weyden (1399/1400-1464) was selected for investigation. Data were compared with reference compounds and reference lead white linseed oil paint and egg tempera paint. The static SIMS technique gave position-sensitive mass spectra that were used to image the elemental distribution of pigments and the molecular signature of components of the oleaginous binding medium. SIMS ion images of sodium and aluminum superimposed with the blue pigment ultramarine and those of copper, lead, and calcium with the position of the mineral pigments of azurite, lead white, and chalk, respectively. Preserved monocarboxylic acids of palmitic and stearic acids present as fatty acids and fatty acid lead soaps pointed to the use of linseed oil as a binding medium. Images from the oleaginous binding medium fatty acids show a correlation with the three main paint layers. The observed palmitic/stearic acid ratios for the two ultramarine layers and azurite layers are 1.3, 1.4, and 1.8, respectively. Fatty acids and fatty acid soaps show highest ion yields near lead white, a mineral pigment that serves as a natural chemical drier and is proposed to act as a template for the initial grafting of the polyunsaturated triglycerides of the linseed oil. Almost no fatty acids were detected in other layers visible by light microscopy. The fatty acid lead soaps point toward a mature ionomeric oil paint system that developed over centuries. SIMS evidence for egg tempera, still used in the 15th century, is not detected in the paint cross section. SIMS images correlate well with SEM/EDX, FT-IR and light microscopic images and the SIMS spectral data additionally support the identification of pigment particles, lead soaps, and other binding medium components.

Electron capture dissociation (ECD) of doubly protonated hyperbranched polyesteramide oligomers (1100–1900 Da) was examined and compared with the structural information obtained by low energy collisionally activated dissociation (CAD). Both the ester and amide bonds of the protonated species were cleaved easily upon ECD with the formation of odd electron (OE·+) or even electron (EE+) fragment ions. Several mechanistic schemes are proposed that describe the complex ECD fragmentation behavior of the multiply charged oligomers. In contrast to studies of biomolecules, the present results indicate that consecutive cleavages induced by intramolecular H-shifts are significant for ECD and of less importance for low energy CAD. The capture of an electron by the ionized species results in fragmentation associated with a redistribution of the excess internal energy over the products and the subsequent bond cleavage. Low energy, multiple collision CAD is found to be a more selective dissociation method than ECD in view of the observation that only amide bonds are cleaved for most of the hyperbranched polymers examined with CAD in this study. ECD appears not to provide complementary structural information compared to CAD in the study of hyperbranched polymers, even though a significantly more complex ECD fragmentation behavior is observed. ECD is shown to be of use for the structural characterization of large oligomers that may not dissociate upon low energy CAD. This is a direct result of the fact that ECD produces ionized hyperbranched oligomers with a relatively high internal energy.

A setup for reflection visible light imaging microspectroscopy (VIS-imaging) as well as its evaluation and application is described and tested. The spatial resolution of the system is approximately 1 microm at a spectral resolution of 4 nm. The optical contrast between different colored particles in the surface of a sample is optimized with a new image processing method for mapping of the distribution of the identified pigment particles. The potential of VIS-imaging in the study of paint cross sections obtained from paintings is explored. Spectra obtained from pigment particles in these cross sections result in classification or identification of several pigments. The investigated paint samples are challenging test cases, as they contain several colored materials with a very fine distribution. VIS-imaging can identify and map the most common traditional blue pigments, i.e., smalt, azurite, ultramarine, and indigo in 17th century oil paintings. Smalt can be identified even after complete discoloration. VIS-imaging analysis assisted in the identification and mapping of modern synthetic red and yellow pigments in a 20th century painting.

Methanolic extracts of paint samples of different composition and age were qualitatively investigated by GC–MS using an on-column injector after off-line methylation or trimethylsilyl derivatisation, and on-line thermally assisted (trans)methylation with tetramethylammonium hydroxide using Curie-point pyrolysis–GC–MS. The combination of these three analytical strategies led to the identification of typical oxidation products of unsaturated fatty acids by interpretation of their mass spectrum. Some of the identified compounds have not been reported before. Both the off-line and on-line GC–MS strategy show series of short-chain fatty (di)acids and C16 and (oxidised) C18 fatty acids. The major advantage of the on-line pyrolysis–GC–MS approach is that chemical work-up is minimal and very quick. With this technique both the carboxylic acid functionalities, and hydroxyl groups are methylated. Young paint films are shown to contain relatively more oxidised C18 fatty acids and less diacids compared to older paints, which is indicative for the on-going oxidation processes within the paint. After trimethylsilylation, monoacylglycerols are detected indicative for hydrolytic processes, which reflect the relative distribution of the most prominent silylated fatty acids present. Relatively more C16 and C18 monoacylglycerols are found in young paints, whereas older paints contain higher amounts of monoacylglycerols of diacids.