Pyrolysis Gas Chromatography And Mass Spectrometry Research Articles

Effects of porosity and acidity on deoxygenation and denitrogenation in catalytic pyrolysis of protein-rich microalgae with metal-doped zeolites

The protein-rich defatted microalgae (Nannochloropsis gaditana) after lipid extraction was used as feedstock in catalytic pyrolysis to optimize economic returns of microalgae waste utilization. The effects of Ni- and Co-modified HZSM-5 on the formation of aromatic hydrocarbons (AHs), deoxygenation and denitrogenation in catalytic fast pyrolysis were studied via pyrolysis-gas chromatography and mass spectrometry (Py-GC/MS) at 500°C. Monometallic modified catalysts were synthesized by loading 0.5 wt%, 1 wt%, and 2 wt% of metal species onto HZSM-5 using ion exchange methods. The composition and pyrolysis pathways of primary volatiles detectable by gas chromatography (GC) were investigated, which included phenols, aliphatic hydrocarbons, AHs, acids, furans, N-heterocyclic compounds (N-HCs), amides and nitriles. The relative yields in AHs increased about 10.9 (0.5 wt% Ni/HZSM-5 or Ni0.5), 10.2 (Ni1), 6.8 (Ni2), 7.3 (Co0.5), 9.7 (Co1) and 7.8 (Co2) times compared to the relative yield from defatted microalgae pyrolysis. The doping of metals onto the HZSM-5 altered its porosity and acidity, leading to an impaired diffusion of reactants but also the creation of new acidic sites, which enhanced the selectivity towards monoaromatic hydrocarbons (MAHs) by aromatization and cleavage of N-containing heterocycles via the H radicals formation. Ni-loaded HZSM-5 outperformed Co-modified zeolite with respect to AHs production, deoxygenation and denitrogenation. The specific surface area (SBET) and pore volume were positively correlated with the formation of AHs, while strong acidity showed a strong positive correlation with the generation of nitriles and N-HCs. Relatively low loadings of Ni and Co (0.5–1 wt%) on HZSM-5 (Si/Al = 23) were recommended to decrease the N-containing compounds in pyrolysis vapors from defatted microalgae. The findings may shed light on the development of a high-performance HZSM-5 catalyst for the production of AHs and denitrogenation from protein-rich defatted microalgae.

Catalytic hydropyrolysis of cashew de-oiled shell using Py-GC/MS

The present study delves into the impact of different metal oxides (Al2O3, Nb2O5, CaO, CeO2, and ZrO2) and temperatures (350, 450, and 550℃) on the flash pyrolysis of cashew de-oiled shell. Upon analysis using Pyrolysis Gas Chromatography and Mass Spectrometry (Py-GC/MS), the resulting functionalities, including carbonyls, furans, phenolics, hydrocarbons, sugars, and N-containing compounds, have been identified. Additionally, the potential of flash hydro-pyrolysis to upgrade pyrolysis vapors into fuel-grade hydrocarbons has also been studied. The study investigates the effect of hydrogen pressure variations (1, 5, and 10 bar) and the catalytic activity of metal oxides on hydropyrolysis. Characterization of the metal oxides through BET, XRD, SEM, and TPD reveals distinct properties. Notably, incorporating Al2O3 significantly enhances the production of aliphatic hydrocarbons, reaching 78.4 area% at 10 bar of hydrogen. This research advances our understanding of flash pyrolysis and provides insights into sustainable fuel production through targeted catalytic processes.

Quantitation and identification of microplastics accumulation in human placental specimens using pyrolysis gas chromatography mass spectrometry.

The exponential increase in global plastic usage has led to the emergence of nano- and microplastic (NMP) pollution as a pressing environmental issue due to its implications for human and other mammalian health. We have developed methodologies to extract solid materials from human tissue samples by saponification and ultracentrifugation, allowing for highly specific and quantitative analysis of plastics by pyrolysis-gas chromatography and mass spectrometry (Py-GC-MS). As a benchmark, placenta tissue samples were analyzed using fluorescence microscopy and automated particle count, which demonstrated the presence of >1-micron particles and fibers, but not nano-sized plastic particles. Analyses of the samples (n = 10) using attenuated total reflectance-Fourier transform infrared spectroscopy indicated presence of rayon, polystyrene, polyethylene, and unclassified plastic particles. By contrast, among 62 placenta samples, Py-GC-MS revealed that microplastics were present in all participants' placentae, with concentrations ranging widely from 6.5 to 685 µg NMPs per gram of placental tissue, averaging 126.8 ± 147.5 µg/g (mean±SD). Polyethylene was the most prevalent polymer, accounting for 54% of total NMPs and consistently found in nearly all samples (mean 68.8 ± 93.2 µg/g placenta). Polyvinyl chloride and nylon each represented approximately 10% of the NMPs by weight, with the remaining 26% of the composition represented by 9 other polymers. Together, these data demonstrate advancements in the unbiased quantitative resolution of Py-GC-MS applied to the identification and quantification of NMP species at the maternal-fetal interface. This method, paired with clinical metadata, will be pivotal to evaluating potential impacts of NMPs on adverse pregnancy outcomes.

Characterization and Biological Activities of Melanin from the Medicinal Fungi Ophiocordyceps sinensis.

Melanin is a complex natural pigment that is widely present in fungi. The mushroom Ophiocordyceps sinensis has a variety of pharmacological effects. The active substances of O. sinensis have been extensively studied, but few studies have focused on the O. sinensis melanin. In this study, the production of melanin was increased by adding light or oxidative stress, namely, reactive oxygen species (ROS) or reactive nitrogen species (RNS), during liquid fermentation. Subsequently, the structure of the purified melanin was characterized using elemental analysis, ultraviolet-visible absorption spectrum, Fourier transform infrared (FTIR), electron paramagnetic resonance (EPR), and pyrolysis gas chromatography and mass spectrometry (Py-GCMS). Studies have shown that O. sinensis melanin is composed of C (50.59), H (6.18), O (33.90), N (8.19), and S (1.20), with maximum absorbance at 237 nm and typical melanin structures such as benzene, indole, and pyrrole. Additionally, the various biological activities of O. sinensis melanin have been discovered; it can chelate heavy metals and shows a strong ultraviolet-blocking ability. Moreover, O. sinensis melanin can reduce the levels of intracellular reactive oxygen species and counteract the oxidative damage of H2O2 to cells. These results can help us to develop applications of O. sinensis melanin in radiation resistance, heavy metal pollution remediation, and antioxidant use.

The application of TMAH thermochemolysis on the detection of nucleotides: applications for the SAM and MOMA space experiments

The Sample Analysis at Mars (SAM) instrument onboard the Curiosity rover and Mars Organic Molecule Analyzer (MOMA) instrument onboard the ExoMars rover are two of the most important instruments used for the in-situ search for biosignatures of life on Mars. Tetramethylammonium hydroxide (TMAH) thermochemolysis combined with pyrolysis-gas chromatography and mass spectrometry (Py-GC/MS) has been one of the main techniques utilized by SAM and will be utilized by MOMA. They are both capable of detecting molecular fragments and patterns indicative of life in the Martian near-surface. This study identifies the TMAH thermochemolysis products of targeted nucleotides using flash pyrolysis and SAM-like ramp pyrolysis experiments. Additionally, the optimal TMAH thermochemolysis temperature was determined. Results indicate that the methylated nucleosides can be detected at low abundances when exposed to TMAH thermochemolysis flash pyrolysis at 200 °C. Notably, higher pyrolysis temperatures led to the degradation of nucleosides. Furfuryl methyl ether, one of the degradation products of these nucleosides, was also identified from 200 to 600°C in this study. 300 °C is the optimal temperature for the detection of methylated phosphate under flash pyrolysis of the tested nucleotides with TMAH thermochemolysis. Methylated nucleobases, methyl furfuryl and methyl phosphate are the main products of the tested nucleotides under SAM-like ramp thermochemolysis. Ramped thermochemolysis also resulted in improved performance over flash pyrolysis in the detection of characteristic nucleotide compounds. Uracil and thymine can be detected by both SAM and MOMA if there are nucleotides on Mars; additionally, MOMA will be able to detect adenine. Therefore, methyl furfuryl, methylated phosphate, and the methylated nucleobases uracil, thymine, and adenine are the organic compounds that should be within the SAM and MOMA detection windows if there is DNA/RNA conserved in Martian soil. These experiments will provide a reference for the data collected in-situ by the Curiosity rover and the future ExoMars rover.

Composition, Properties, and Utilization of Fumaric Acid Sludge By-Produced from Industrial Phthalic Anhydride Wastewater Treatment

To understand fumaric acid sludge (FAS) systematically and comprehensively and find out how to utilize it, we conducted a series of characterization analyses on FAS. Fourier transform infrared (FT-IR) Spectra shows that the main component of FAS is fumaric acids and also contains a small amount of silicate. The nuclear magnetic resonance hydrogen (1H-NMR) spectrum also shows that fumaric acid accounted for a large proportion of FAS. The X-ray diffraction (XRD) shows that the main phase in FAS is fumaric acid, and there is also a small amount of Kaliophilite. After gas chromatography and mass spectrometry (GC-MS) and pyrolysis gas chromatography and mass spectrometry (Py-GC-MS) analysis, it indicates that the possible volatiles and pyrolysis products in FAS are fumaric acid, maleic acid, maleic anhydride, phthalic acid, etc. In the test of Liquid chromatography and mass spectrometry (LC-MS), we determined the contents of phthalic acid, fumaric acid, and maleic acid in FAS. The detailed mass content of each component in FAS is as follows: phthalic acid is about 0.10-0.15%; maleic anhydride is about 0.40-0.80%; maleic acid is about 18.40-19.0%; fumaric acid is about 55.00-56.90%; succinic anhydride is about 0.06-0.08%; acrylic acid is about 0.06-0.08%; malic acid is about 0.90-1.00%; acetic acid is about 0.10-0.20%; silicate is about 0.25-0.30%; phthalic anhydride is about 0.20-0.30%; water is about 24.30-24.80%. The filtrate loss reducer (PAAF) used in oilwell drilling fluids synthesized by FAS not only has excellent temperature and complex saline resistance, the API filtration loss (FL) was only 13.2 mL/30 min in the complex saline based mud, but is also cost-effective.

The application of TMAH thermochemolysis on the detection of nucleosides: Applications for the SAM and MOMA instruments

Tetramethylammonium hydroxide (TMAH) thermochemolysis has been utilized by the Curiosity rover’s Sample Analysis at Mars (SAM) instrument and will be utilized by the ExoMars 2022′s Mars Organic Analyzer (MOMA) instrument. TMAH thermochemolysis is one of the main techniques that enables the detection of bioindicators when it is combined with pyrolysis-gas chromatography and mass spectrometry (Py-GC/MS) at the surface of Mars. This study identifies the thermochemolysis products of targeted nucleosides using flash pyrolysis and a SAM-like ramp pyrolysis. Results indicate that the methylated nucleosides can be detected when nucleosides are submitted to TMAH thermochemolysis, which demonstrates that the TMAH thermochemolysis protocol does not result in the decomposition of the nucleosides. To detect the whole structure of each nucleoside, low thermochemolysis temperature is required. 200 °C is the optimal temperature. Methylated nucleobases are the main products of the tested nucleosides when the thermochemolysis temperature is higher than 300 °C. Furfuryl methyl ether, one of the degradation products of these nucleosides, were also identified from 200° to 600°C in this study. These experiments will establish a reference database for interpretation of the data acquired by the SAM and MOMA experiments during operations on Mars.

Holocene pyrolytic nitrogen compounds by using pyrolysis-GC/MS and its paleoclimatic implication from Jinchuan peatbog, NE China

We present a Holocene record of pyrolytic nitrogen (N) composition from the Jinchuan peat bog within the Longgang Volcanic Field (LVF), NE China. Based on pyrolysis gas chromatography and mass spectrometry (Py-GC/MS) analysis, N-compounds including acetamide, NHetero and NAro have been identified and quantified. Aromatic N-compounds (NAro, benzonitrile and benzamide) are mainly derived from phytoplankton and higher plants, and are resistant to microbial degradation. We propose ‘NHetero/NAro’ as a proxy based on microbial degradation, and has lower values between 10 and 5.8 ka BP, and higher values during the late Holocene. We suggest that temperature is main factor for NHetero/NAro, and sedimentary facies changed from floodplain to peat deposition, variation of effective precipitaion and pH value have limited influence on the performance of the proxy in Jinchuan. Low NHetero/NAro levels, combined with high levels of non-protein derived acetamide, indicate warmer conditions, and vice versa. NHetero/NAro is sensitive to temperature change, and follows a similar pattern to those of previous paleo-temperature time series derived from br-GDGT and long chain alkenones in this region. This Spectral analysis of the NHetero/NAro time series reveals significant periodicities of 103–105, 145 and 482–506 years, suggesting strong influences of solar radiation and monsoon intensity on temperature variations in NE China during the Holocene.

Pyrolysis kinetics and determination of organic components and N-alkanes yields of Karamay transformer oil using TG, FTIR and Py-GC/MS analyses

In this study, the pyrolysis characteristics of Karamay transformer oil are studied using Thermogravimetry (TG), Fourier Transform Infrared (FTIR), and Pyrolysis Gas Chromatography and Mass Spectrometry (Py-GC/MS) analysis. Four model-free methods of Friedman, Starink, KAS, FWO and one model-fitting method of Multivar-NLR are applied to determine the pyrolysis kinetics. The results show that the apparent activation energy varies less than 10% from 0.05 to 0.95 conversion rate regardless of the calculation method, and the average value is 40.24 kJ/mol, which is close to that of diesel, 35.82 kJ/mol. The best-fit kinetic model for characterizing the pyrolysis of transformer oil is the order-based kinetic model of f(α) = (1 − α)0.46 where the pyrolysis reaction rate is a function of the concentration of remaining reactants. The results of FTIR indicate that there is a large amount of alkanes with a higher number of carbon atoms and a small amount of aromatic hydrocarbons in the original transformer oil, while no unsaturated carbon has been identified. Consequently, the pyrolysis of transformer oil produces organic products including the n-alkanes, branched-chain alkanes, olefins, alcohols and phenols. Through Py-GC/MS analysis, n-alkanes are identified as the major group of volatile products by mass. The yields of n-alkanes are quantified using the external standard method in Py-GC/MS analysis where the results show that Karamay transformer oil presents the characteristic of “single peak with odd carbon predominance”, consistent with the characteristic of the recent sediments in China. The total yield of n-alkanes is 0.55 ± 0.06 g/g with n-heptadecane (C17) as the primary volatile product. The n-alkanes yield of transformer oil is higher than that of gasoline, 0.41 g/g and similar to that of diesel, 0.52 g/g. The dominating heavy components of Karamay transformer oil have higher carbon numbers than those of crude oils in other areas of the world. The current research provides theoretical and experimental basis for either direct use or further refinement of transformer oil into environmentally friendlier alternatives.

A review on the modeling and validation of biomass pyrolysis with a focus on product yield and composition

Modeling is regarded as a suitable tool to improve biomass pyrolysis in terms of efficiency, product yield, and controllability. However, it is crucial to develop advanced models to estimate products' yield and composition as functions of biomass type/characteristics and process conditions. Despite many developed models, most of them suffer from insufficient validation due to the complexity in determining the chemical compounds and their quantity. To this end, the present paper reviewed the modeling and verification of products derived from biomass pyrolysis. Besides, the possible solutions towards more accurate modeling of biomass pyrolysis were discussed. First of all, the paper commenced reviewing current models and validating methods of biomass pyrolysis. Afterward, the influences of biomass characteristics, particle size, and heat transfer on biomass pyrolysis, particle motion, reaction kinetics, product prediction, experimental validation, current gas sensors, and potential applications were reviewed and discussed comprehensively. There are some difficulties with using current pyrolysis gas chromatography and mass spectrometry (Py-GC/MS) for modeling and validation purposes due to its bulkiness, fragility, slow detection, and high cost. On account of this, the applications of Py-GC/MS in industries are limited, particularly for online product yield and composition measurements. In the final stage, a recommendation was provided to utilize high-temperature sensors with high potentials to precisely validate the models for product yield and composition (especially CO, CO2, and H2) during biomass pyrolysis.

Investigation of Synthesis Mechanism, Optimal Hot-Pressing Conditions, and Curing Behavior of Sucrose and Ammonium Dihydrogen Phosphate Adhesive.

In this study, a further investigation was carried out on the synthesis mechanism, optimal manufacturing conditions, and curing behavior of a sucrose-ammonium dihydrogen phosphate (SADP) adhesive. The results of 13C nuclear magnetic resonance (NMR) spectroscopy confirmed that SADP was composed of 5-hydroxymethylfurfural (5-HMF), deoxyfructosazine (DOF), amino compounds, Schiff base, monosaccharides, and oligosaccharide. The optimal hot-pressing conditions were a hot-pressing temperature of 170 °C, a hot-pressing time of 7 min, and a spread rate of 120 g/m2. The wet shear strength of plywood bonded at optimal manufacturing conditions met the requirements of China National Standard (GB/T 9846-2015). Thermal analysis and insoluble mass proportion measurements showed that the main curing behavior of the SADP adhesive occurred at curing temperatures higher than 145 °C, and more than 50% insoluble mass was formed when the heating time was longer than 5 min. Fourier-transform infrared spectroscopy (FT-IR) indicated that cross-linking of the cured adhesive was promoted by prolonging the heating time. In addition, pyrolysis gas chromatography and mass spectrometry (Py-GC/MS) confirmed that the cured SADP adhesive was composed of furan and nitrogen-containing compounds.

Investigation and Characterization of Synthesis Conditions on Sucrose-ammonium Dihydrogen Phosphate (SADP) Adhesive: Bond Performance and Chemical Transformation.

Sucrose is one of the most abundantly available renewable chemicals in the world, and it is expected to be utilized as a raw material for wood-based material products. Herein, a novel adhesion system that was based on sucrose and ammonium dihydrogen phosphate (ADP) was synthesized into an adhesive with 80% solid content, and this eco-friendly was utilized on the fabrication of plywood. The effects of the synthesis conditions on the plywood bond performance and synthesis mechanism were investigated. The optimal synthesis conditions were as follows: the mass proportion between sucrose and ADP was 90/10, the synthesis temperature was 90 °C, and the synthesis time was 3 h. The bonding performance of the plywood that was bonded by optimal SADP adhesive satisfied the GB/T 9846-2015 standard. The chemical analysis was performance tested by using High-Performance Liquid Chromatography (HPLC), Attenuated Total Reflection-Fourier Transform Infrared Spectra (ATR-FTIR), and Pyrolysis Gas Chromatography and Mass Spectrometry (Py-GC/MS) to understand the chemical transformation during the synthesis process. The chemical analysis results confirmed that the hydrolysis and conversation reaction of sucrose occurred in the synthesized SADP adhesive, and ADP promoted the pyrolysis efficiency of sucrose.

TG-FTIR and Py-GC/MS analyses of pyrolysis behaviors and products of cattle manure in CO2 and N2 atmospheres: Kinetic, thermodynamic, and machine-learning models

The increased amounts of manure have become an issue of environmental management due to the rapid growth of livestock industry. This study quantified the pyrolytic performance and gaseous products of cattle manure using (derivative) thermogravimetric ((D)TG), Fourier transform infrared spectrometry (FTIR) and pyrolysis–gas chromatography and mass spectrometry (Py-GC/MS) analyses. The pyrolysis process of cattle manure was determined to occur in three stages, with the main reaction in the range of 161–600 °C. The N2 atmosphere was found to be more favorable for the release of volatiles according to a higher comprehensive pyrolysis index in the range of 30−600 °C. The lower activation energies were shown to be required in the CO2 than N2 atmosphere. Random forests algorithm outperformed multiple linear regression, gradient boosting machine, and artificial neural networks for the prediction of mass loss due to the cattle manure pyrolysis. The main gaseous products were CO2, phenol (23.23%), and furans (12.98%). The theoretical and practical guidance for the energy and resource utilization of cattle manure was provided by this study.

Polyvinyl Alcohol Reinforced Flame-Retardant Polyacrylonitrile Composite Fiber Prepared by Boric Acid Cross-Linking and Phosphorylation.

To improve the strength and maintain the inherent properties of flame-retardant polyacrylonitrile (FR-PAN) fiber, a commercialized hydrocarbon polymer, i.e., poly (vinyl alcohol) (PVA), used as an enhancement component, was blended with polyacrylonitrile (PAN) spinning dope to fabricate a PVA/PAN composite fiber through wet-spun technology. Then, cross-linked PVA/PAN composite fiber (C-PVA/PAN) was acquired via boric acid cross-linking. Finally, flame-retardant C-PVA/PAN fiber (FR-PVA/PAN) was prepared by phosphorylation. The structures of the samples were characterized by Fourier transform infrared analysis (FTIR) and X-ray photoelectron spectroscopy (XPS). The thermogravimetric analysis (TGA) results reveal that the thermal stability of the composite fiber is lower than that of the pristine PAN fiber. However, the char residue of the composite fiber is higher than that of the control sample, wherein, FR-PVA/PAN has the highest char residue of 62.5 wt% at 800 °C. The results regarding the combustion properties of FR-PVA/PAN show that the fire hazard of FR-PVA/PAN is restrained greatly, indicating excellent flame-retardant performance. The corresponding flame-retardant mechanism of FR-PAV/PAN is investigated by Pyrolysis gas chromatography and mass spectrometry (Py-GC/MS) and thermogravimetric analysis coupled with Fourier transform infrared analysis (TG-FTIR). The results indicate the gas-phase and condensed-phase flame-retardant mechanisms.

Persistently flame-retardant flexible polyurethane foams by a novel phosphorus-containing polyol

To overcome the poor compatibility, easy migration of additive flame retardants, a novel polyester polyol (DMOP) was synthesized from dimethyl methylphosphonate and diethanol amine through transesterification and used in the foaming formula to prepare inherent flame-retardant flexible polyurethane foams (FPUFs). DMOP mainly play soft segments in the foams which increases the flexibility and elongation at break. With a low incorporation amount of 10 php (ca. 6.3 wt%), the resultant FPUF can pass vertical burning test. More importantly, accelerated ageing tests at 140 °C for 64 h indicate the persistent flame retardancy of DMOP for FPUF. The thermogravimetric analysis (TGA) results reveal their lower thermal stability than that of ordinary polyurethane. The corresponding flame-retardant mechanism of DMOP-containing FPUFs is investigated by Pyrolysis gas chromatography and mass spectrometry (Py-GC/MS) and FTIR, which indicates the phosphorus in DMOP mainly played their role in the vapor phase. This work thus offers a facile route for preparing FPUFs with persistent, efficient flame retardancy.

The mechanical and photoelastic properties of 3D printable stress-visualized materials

Three-dimensional (3D) printing technology integrating frozen stress techniques has created a novel way to directly represent and characterize 3D interior discontinuities and the full-field stress induced by mining- or construction-related disturbances of deeply buried rock masses. However, concerns have been raised about the similitude between the mechanical behaviours of the printed model and its prototype rock mass. Ensuring the mechanical properties of the printable materials are as close as possible to those of real rock mass is of critical significance. In this work, a transparent, light, photosensitive polymer material was investigated for applications in frozen stress tests. The chemical composition of the material was determined by integrating the results of infrared spectroscopy (IR spectroscopy), X-ray diffraction (XRD), pyrolysis, gas chromatography and mass spectrometry (PY-GC/MS). Measures to improve the mechanical properties of the printable material, including printing orientation, post-processing, and temperature control, were evaluated by comparing the treated material with its prototype rock. The optical stress sensitivity of the material, including stress-visualized properties and stress-frozen performance, was also tested. This study offers an understanding of how printable materials should be modified to better simulate real rock masses, in terms of not only their geological geometry but also their mechanical performance.

Characterization of Tang Dynasty lamp oil remains by using pyrolysis gas chromatography and mass spectrometry

This paper presents the results of the analysis investigation of the lamp oil remains from a Tang Dynasty tomb (901 AD) in Lin An County, Zhejiang Province of China. The techniques applied include direct pyrolysis gas chromatography and mass spectrometry (Py-GC/MS), Py-GC/MS with in-situ hydrolysis and methylation, as well as Py-GC/MS with double-shot method. Through the analysis, plant oil—most likely perilla oil was identified in the sample. The detection of the aromatic compounds (such as calamene, calamenene, cycloisolongifolene, 8,9-dehydro-neoisolongifolene, cadalene, cedrene, ylangene, cuparene and cedrol) indicates the presence of cedar oil and other essential oils in the lamp remains. Unexpectedly, the marker compounds of urushi including methyl 7-(2,3-dimethoxyphenyl) heptanoate, methyl 9-(2,3-dimethoxyphenyl) nonanoate and 1,2-dimethoxy-3-pentadecylbenzene were also detected in the sample.

A comparison study of alkyd resin used in art works by Py-GC/MS and GC/MS: The influence of aging

In order to study the drying process and the degradation processes of alkyd resins, different types of alkyds for art works were investigated by pyrolysis-gas chromatography and mass spectrometry (Py-GC/MS) with double-shot technique, thermally assisted hydrolysis and methylation (THM-GC/MS) as well as GC/MS after derivatized with the reagent of m-trifluoromethylphenyl trimethylammonium (Meth-Prep II) methods. By using Py-GC/MS with double-shot technique, the oxidization products of alkyds including 2-octenal, 2-decenal, 2,4-decadienal, nonanal and 2-undecenal could be detected during drying, while the main component of alkyd – phthalic anhydride was found in higher amount in aged samples than unaged ones, indicating the formation of free phthalic anhydride during aging. The characterization of the main components of alkyds such as dibasic acid, polyol and drying oil can be achieved by using the techniques (THM-GC/MS) and GC/MS with the derivatization reagent Meth-Prep II. The decrease of unsaturated fatty acids and increase of phthalic anhydride were observed in the aged alkyd samples by those two techniques. The complementation of different analytical techniques provided several and different results, which are useful for a better understanding of the drying and degradation properties of alkyd resins.

Identification of the materials used in an Eastern Jin Chinese ink stick

Abstract Chinese ink stick has a long history and a special importance in the Chinese culture. For the first time, Pyrolysis Gas Chromatography and Mass Spectrometry (Py-GC/MS) was used to identify the materials in an ancient Chinese ink stick. Four types of constituents could be detected in the archaeological ink stick of the Eastern Jin period (317–420 AD): (1) borneol (Chinese name bing pian); (2) compounds related to essential oil or tar of conifer wood: cedrene, aromadendrane, cedrane, cuparene, cedrol, retene, methyl dehydroabietate and 9-methyl retene; (3) marker compounds from animal glue; (4) polycyclic aromatic hydrocarbons (PAHs) from soot. The information obtained through this study provides conclusive evidence for use of additives of borneol and cedar oil, binding media of animal glue and pine wood soot in the ancient ink stick.

Analytical characterization of lacquer objects excavated from a Chu tomb in China

This work presents the results of an investigation of the lacquer objects excavated from a Chu tomb in China (Warring States, 481–221 BC). This study is engaged in the examination of the methods and the materials used for the urushi coating on the objects. X-Ray fluorescence and Scanning Electron Microscopy/Energy Dispersive Using X-Ray (SEM/EDX) analyses were applied for the pigment identification. The results show that vermilion was for the red colour, while carbon black was for the black colour. Pyrolysis gas chromatography and mass spectrometry (Py-GC/MS) was applied for the characterization of the lacquer resulting that it is based on urushi. The possibility to classify the drying oil (tung or linseed oil) present in the lacquer is highlighted and discussed in this paper. Py-GC/MS with in-situ hydrolysis and methylation reagent tetramethylammonium hydroxide (TMAH) were performed on reference materials of linseed oil and tung oil as well as on the lacquer object samples. The results show that it is possible to unambiguously identify the drying oil, in our case, linseed oil was identified to retard the rate of hardening.