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Abstract Background Microplastics, widely present in the environment, are implicated in disease pathogenesis through oxidative stress and immune modulation. Prevailing research, primarily based on animal and cell studies, falls short in elucidating microplastics' impact on human cardiovascular health. This cross-sectional study detected blood microplastic concentrations in patients presenting with chest pain using pyrolysis–gas chromatography/mass spectrometry and evaluating inflammatory and immune markers through flow cytometry, to explore the potential effects of microplastic on acute coronary syndrome. Results The study included 101 participants, comprising 19 controls and 82 acute coronary syndrome cases. Notably, acute coronary syndrome patients exhibited elevated microplastic concentrations, with those suffering from acute myocardial infarction presenting higher loads compared to those with unstable angina. Furthermore, patients at intermediate to high risk of coronary artery disease displayed significantly higher microplastic accumulations than their low-risk counterparts. A significant relationship was observed between increased microplastic levels and enhanced IL-6 and IL-12p70 contents, alongside elevated B lymphocyte and natural killer cell counts. Conclusion These results suggest an association between microplastics and both vascular pathology complexity and immunoinflammatory response in acute coronary syndrome, underscoring the critical need for targeted research to delineate the mechanisms of this association. Highlights 1 Blood microplastic levels escalate from angiographic patency, to angina patients, peaking in myocardial infarction patients. 2 Microplastics in acute coronary syndrome patients are predominantly PE, followed by PVC, PS, and PP. 3 Microplastics may induce immune cell-associated inflammatory responses in acute coronary syndrome patients. Graphical abstract

Polystyrene microplastics, especially those smaller than 10 μm, reduce male fertility in murine models, but whether they affect male reproduction in humans is poorly understood. Here, we studied polystyrene microplastics smaller than 10 μm in human semen samples and evaluated their toxicity to human sperm. We also tested the use of magnetic iron oxide nanoparticles to remove nanoplastics and decrease their toxicity in human sperm. Results show that human semen is contaminated by approximately 3.57 ± 0.32 μg/mL polystyrene microplastics smaller than 10 μm. Polystyrene nanoplastics of 25–100 nm penetrate and damage human sperm at semen-relevant concentrations of 5 and 50 μg of nanoplastic per mL, while 0.5–10 μm polystyrene microplastics bind to the sperm. We also found that 25-nm polystyrene nanoplastics exhibited a synergistic toxicity with bisphenol A on human sperm. Nonetheless, we observed that environmental microplastics released from disposable paper cups do not pose a significant hazard to human sperm under our conditions. Furthermore, magnetic iron oxide nanoparticles can aggregate and coprecipitate with 25-nm polystyrene nanoplastics to eliminate their adverse effects on human sperm. [ABSTRACT FROM AUTHOR]

The quantification analysis of microplastics (MPs) in bottled water, purified tap water and branded table salt was executed by double-shot pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS), and the concentration was expressed as a mass concentration, which was more suitable for the data comparison. MPs including polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polycarbonate (PC), polypropylene (PP), polystyrene (PS) and polyethylene (PE) were separated by filtration with glass fiber filter membranes. After being folded, the whole glass filter membrane containing MPs was transferred into a pyrolysis cup directly to avoid the sample loss during transfer. The characteristic pyrolysates were used to identify and quantify PMMA, PET, PC, PP, PS and PE. The linear relationships were found between the polymer weight amount and peak areas of each characteristic pyrolysates with the correlation coefficients larger than 0.993. The intra-day precisions of the pyrolysates for peak areas were 0.56–18.94%, and the inter-day variability was 8.47–19.88%. The recovery values of the spiked standards were in a range of 81.5–114.5%. MPs in bottled water, purified tap water and branded table salt samples were successfully quantified by the proposed Py–GC/MS method. For four brands of bottled water samples, 0.088 μg/L PET was found in one sample. PP was detected in all purified tap water samples from five brands with the concentrations between 0.028 and 0.489 μg/L, and PE was detected in purified tap water samples from two brands with the concentrations between 0.194 and 1.26 μg/L. As for nine table salt samples, PP were found in a range of 4.00–182.80 μg/100 g salt in eight table salt samples. Due to the high content of MPs in purified tap water samples and large daily consumption, the estimated daily intake (EDI) of MPs from purified tap water was calculated. The estimated daily intakes (EDIs) for adults are 2.57 ng PP/kg/d and 4.17 ng PE/kg/d from purified tap water; the EDIs for children are 5.63 ng PP/kg/d and 9.11 ng PE/kg/d from purified tap water. [ABSTRACT FROM AUTHOR]

Background: Microplastics, widely present in the environment, are implicated in disease pathogenesis through oxidative stress and immune modulation. Prevailing research, primarily based on animal and cell studies, falls short in elucidating microplastics' impact on human cardiovascular health. This cross-sectional study detected blood microplastic concentrations in patients presenting with chest pain using pyrolysis–gas chromatography/mass spectrometry and evaluating inflammatory and immune markers through flow cytometry, to explore the potential effects of microplastic on acute coronary syndrome. Results: The study included 101 participants, comprising 19 controls and 82 acute coronary syndrome cases. Notably, acute coronary syndrome patients exhibited elevated microplastic concentrations, with those suffering from acute myocardial infarction presenting higher loads compared to those with unstable angina. Furthermore, patients at intermediate to high risk of coronary artery disease displayed significantly higher microplastic accumulations than their low-risk counterparts. A significant relationship was observed between increased microplastic levels and enhanced IL-6 and IL-12p70 contents, alongside elevated B lymphocyte and natural killer cell counts. Conclusion: These results suggest an association between microplastics and both vascular pathology complexity and immunoinflammatory response in acute coronary syndrome, underscoring the critical need for targeted research to delineate the mechanisms of this association. Highlights: Blood microplastic levels escalate from angiographic patency, to angina patients, peaking in myocardial infarction patients. Microplastics in acute coronary syndrome patients are predominantly PE, followed by PVC, PS, and PP. Microplastics may induce immune cell-associated inflammatory responses in acute coronary syndrome patients. [ABSTRACT FROM AUTHOR]

The thermolysis of waste tobacco filters (WTFs) was carried out and characterized by thermogravimetric analysis (TGA) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The WTFs showed four distinctive derivative TG (DTG) peaks. Such distinctive DTG curves were indicative of the thermal desorption of triacetin (< 220°C), thermal desorption of glycerol tricaprylate (221-270°C), decomposition of cellulose acetate (CA, 281-400°C), and char stabilization (> 400°C). The activation energy (Ea) (223-279 kcal kg-1) in the additives desorption region (220-270°C) were higher than those (169 ± 5.1 kcal kg-1) from the WTFs at the main decomposition region of CA (281-400°C). Py-GC/MS suggested that a large amount of acetic acid (AA, 33.0 wt.%) was recovered as the major pyrogenic product stemming from WTF. An increase in AA purity up to 76.2% (except for CO2) was achieved in the 2nd Py step at 400°C after eliminating the non-target chemicals (nicotine, triacetin, glycerol tricaprylate, and 2-(decanoyloxy)propane-1,3-diyl dioctanoate) through the 1st thermal desorption (TD) step to 300°C. [ABSTRACT FROM AUTHOR]

Mountain ecosystems exhibit rapid changes in vegetation cover and climate conditions along elevation gradients, offering an ideal natural experiment to examine variations in the molecular composition of soil organic carbon (SOC) responsing to environmental change. We examined molecular composition, diversity, and network complexity of SOC using the pyrolysis-gas chromatography/mass spectrometry technology and the Shannon diversity index (SHDI) in Changbai Mountain (CBS). Results indicated that molecular composition of SOC differed greatly across different vegetation zones, which were predominated by mixed coniferous and broad-leaved forests (HJL), mixed coniferous forests (ZYL), birch forest covered (YHL), and tundra vegetation (TYD). ZYL had remarkably more abundant moieties with aromatic structures, 36% on average, than those in HJL, TYD, and YHL, 18.31%, 12.75% and 16.51% on average, respectively. O-alkyl, alkyl, and terpene compounds showed an increasing trend, whereas aromatic, lignin and nitrogen-containing compounds exhibited a notable decrease with elevation to a significant level. Either alpha diversity or beta diversity of SOC varied significantly among TYD, YHL, ZYL, and HJL, with HJL exhibiting the lowest alpha diversity. SOC from ZYL was the most complex, showing the highest number of edges and graph density. Leaf litter elements greatly regulated the molecular diversity and network complexity of SOC. Positive correlations between SHDI and SOC contents, as well as ratios of SOC to total iron, suggested that high molecular diversity promoted SOC persistence in mountain ecosystems.

The bound acrylonitrile content in nitrile rubber (NBR) was determined by pyrolysis-gas chromatography/mass spectrometry, and the effects of furnace temperature and sample amount on pyrolysis were investigated. The butadiene and acrylonitrile fragments were identified by mass spectrometry, and the relationship between peak height ratio of acrylonitrile to butadiene and content ratio of acrylonitrile to butadiene was also established. Furthermore, the test results were compared with those determined by Kjeldahl method. The experiment results showed that the butadiene and acrylonitrile fragments in NBR had good chromatographic peak shape and recognition under the conditions of pyrolysis temperature of 600 ℃ and sample mass of 0.3-0.6 mg. The peak height of acrylonitrile with extracted ion M/Z 53 was positively correlated with the content of bound acrylonitrile in NBR, and the linear correlation coefficient of quantitative curve was above 0.99. Compared with Kjeldahl method, the absolute deviation of this method for determination of bound acrylonitrile content was not more than 0.7%.

The mural paintings of the Second Tomb of the Southern Tang Dynasty in Nanjing, Jiangsu Province, which is the largest in scale during the Five Dynasties and Ten Kingdoms period in southern China, are selected as the objects of study, on the basis of optimization of the test conditions of the egg white standard samples by using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) analysis technique. Eight inorganic mineral pigments such as calcite, lead tetroxide, ochre, cinnabar, azurite, mineral green, orpiment and realgar on the cleavage products are evaluated for the first time and a method is established for the identification of egg whites in the tomb murals. The Py-GC/MS analytical method is developed for the identification of egg whites in tomb murals. The results of the analysis of the artifact samples show that egg whites are added to the mural ground battles, mortars and pigments as cementing materials, and the results of the Py-GC/MS analysis are verified using enzyme-linked immunosorbent assay (ELISA), further demonstrating that Py-GC/MS is a reliable analytical method for egg white composition in tomb murals. This study provides a methodological reference for the study of organic binding media in tomb murals. [ABSTRACT FROM AUTHOR]

In this study, a pyrolysis-gas chromatography/mass spectrometry method was established to quantify microplastics (MPs) released from plastic food containers during rinsing and migration. The inner surface of actual samples was rinsed with deionized water, and the MPs in rinse water were collected through a glass fiber membrane with pore size of 1 μm. Subsequently, thoroughly cleaned polypropylene (PP) food packaging containers were selected for migration tests under different simulants, migration temperatures, and migration times. It was found that MPs corresponding to the materials of product manufacture were detected in all collected containers during rinsing. By migration tests, the results showed that high-fat foods, high/low temperature (5 °C), and long exposure periods can promote the release of MPs. It was also proved that the migration of MPs from plastic food containers was one of the important sources for human exposure to MPs. The obtained results can provide evidence for the safety risk assessment of plastic food containers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Chuju, a cultivar of Chrysanthemum morifolium, has been traditionally cultivated for over 2000 years in China for both ornamental and medicinal purposes. To date, investigations into the chemical composition of this plant have indicated that it contains compounds with extensive biological activities, although detailed information on the chemical composition of Chuju remains scarce. In the present study, the chemical compositions of Chuju flowers were investigated across five sites in the core Chuju planting area in Anhui province, China. Analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was used to explore variations in flower chemical fingerprints from different Chuju planting sites. The study identified approximately 200 components in Chuju flowers and stems, including high levels of fatty acids, lipids, polysaccharides and terpenoids. Multivariate statistical analysis indicated that 16 chemical compounds were influential determinants of the chemical fingerprint and could be used to distinguish two clusters in the five core planting areas. The established Py-GC/MS analytical workflow could provide a basis for determining the chemical fingerprints of Chuju and help elucidate that products contain a reproducible content of bioactive compounds and overall quality for potential development of health and medicinal purposes., (© 2024 Wiley-VHCA AG, Zurich, Switzerland.)

Particulate matters (PMs) such as PM10 and PM2.5 were collected at a bus stop and were analyzed using pyrolysis-gas chromatography/mass spectrometry to identify organic polymeric materials in them. The major pyrolysis products of the PM samples were isoprene, toluene, styrene, dipentene, and 1-alkenes. The pyrolysis products generated from the PM samples were identified using reference polymeric samples such as common rubbers (natural rubber, butadiene rubber, and styrene-butadiene rubber), common plastics (polyethylene, polypropylene, polystyrene, and poly(ethylene terephthalate)), plant-related components (bark, wood, and leaf), and bitumen. The major sources of the principal polymeric materials in the PM samples were found to be the abrasion of the tire tread and asphalt pavement, plant-related components, and lint from polyester fabric. The particles produced by the abrasion of the tire tread and asphalt pavement on the road were non-exhaustive sources, while the plant-related components and lint from polyester fabric were inflowed from the outside. [ABSTRACT FROM AUTHOR]

The surface decoration layers of Samantabhadra Bodhisattva and Thousand Hand Guanyin from Dazu Rock Carvings were examined using digital microscopy, energy-dispersive spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and pyrolysis—gas chromatography/mass spectrometry using thermally assisted hydrolysis and methylation. Gypsum was present in the preparation layer, while the painted layer included lacquer sap (urushiol). The presence of heat-bodied tung oil and resin (benzoin resin) was also detected in some painted layers. Mineral pigments were found in the painted layers, including cinnabar, lead red, orpiment, litharge, and carbon. In addition, there was a layer of gold foil on the surface of the Thousand Hand Guanyin sample. The mass percentage of gold was 96.70%. The gold foil contained gold, silver, copper, and iron as a solid solution. This study provides a reference for the study and protection of cultural relic samples from grottoes. [ABSTRACT FROM AUTHOR]

Abstract For conservation and restoration purposes, the precious historical rubbings preserved in Wuyuan Museum were studied by multi-analytical techniques including 14C radiocarbon dating, scanning electron microscopy (SEM), Pyrolysis–Gas Chromatography/Mass Spectrometry (Py-GC/MS) and Herzberg staining method. The results showed that the Py-GC/MS method is an efficient method for identifying the raw materials of paper and ink in historical rubbings simultaneously. Through Py-GC/MS analysis, five types of constituents could be detected: (1) polycyclic aromatic hydrocarbons (PAHs) from soot; (2) compounds related to tar of conifer wood: retene and methyl dehydroabietate; (3) marker compounds from the whole egg; (4) additive compounds: menthol and curcumene, which were found for the first time in ink; (5) biochemical compounds from bark paper: β-amyrin and α-amyrin. Based on the above results, the ink type, binding media and additives in ink, as well as the fiber origin of the rubbing paper could be concluded. This study could not only provide scientific support for conservation and restoration of the historical rubbings preserved in Wuyuan museum, but also give method guidance for analysis of the uncharacterized rubbings from different origins.

The carbon cycle in ecosystems is fundamentally controlled by the composition and transformation of organic molecules. Alpine wetland soils have enormous carbon storage, but they are sensitive to climate change, and can easily shift from carbon sink to carbon source. However, we currently lack understanding in molecular-chemical composition of soil organic matter (SOM) in alpine wetlands. In this study, we tried to decipher molecular-chemical features of SOM in typical alpine wetlands using the pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Results indicated that nitrogen-containing compounds were the most abundant moieties among pyrolytic products of SOM. More than 83 % of pyrolytic moieties had a molecular weight of no more than 200 Daltons and a H/C ratio of no more than 2.0. O/C ratio of most pyrolytic products were less than 0.5. A van Krevelen diagram potentially indicated that SOM in wetlands might consist of massive heterogeneous molecules where aromatic compounds and their derivatives served as the core, with aliphatic hydrocarbon molecules of varying carbon chain lengths attached externally. About 72.25 % of variances in SOM were explained by 50 pyrolytic products, of which toluene was the most important. A significantly negative relation was observed between molecular weight (MW) and abundance of pyrolytic products, while positive relations were found between H/C, O/C, and abundance of pyrolytic products. Our work implied that SOM in wetlands was mainly composed of molecules with low MW and aromatic function groups. • More than 83 % of the moieties had a molecular weight of no more than 200 Daltons. • Aromatic compounds and their derivatives served as the core of SOM in wetlands. • About 72.25 % of variances in SOM composition were explained by 50 pyrolytic products. [ABSTRACT FROM AUTHOR]

This study was conducted to establish the optimal pyrolysis process for producing high-yield and high-purity acetic acid (AA) from waste cigarette butts (CBs). The waste cigarette filters (CFs) were collected from CBs by shredding and sieving before pyrolysis. The non-isothermal pyrolysis of waste CF was studied using evolved gas analysis-mass spectrometry (EGA-MS) and double-shot pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) with tandem μ-reactor-GC/MS (TMR-GC/MS). EGA-MS of waste CF could differentiate the thermal desorption zones of tobacco additives, such as triacetin and glycerol tricaprylate, from the AA generation zone via cellulose acetate (CA) pyrolysis. The non-isothermal pyrolysis of CA, fresh CF, and waste CF from 100 °C to 400 °C at 20 °C/min resulted in AA as the primary product, with yields of 39.2 %, 34.8 %, and 36.2 %, respectively, along with the formation of additives, such as triacetin (8.8 wt% from waste CF) and glycerol tricaprylate as the main impurity. Despite the potential catalytic conversion of triacetin to AA using a mesoporous catalyst, Al-MCM-41 (SiO 2 /Al 2 O 3 : 25), the catalytic pyrolysis of waste CF did not enhance the high AA yield because of the additional conversion of AA, produced from CA in waste CF, into light hydrocarbons, reducing the AA yield. Finally, the optimized conditions for the highest quantity and quality AA production, achieving a total yield of 40.0 %, were determined to be a two-step selective catalytic conversion: 1) catalytic thermal desorption up to 300 °C using Al-MCM-41 at 350 °C and 2) non-catalytic pyrolysis for CA conversion from 301 °C to 400 °C of waste CF. • Acetic acid was produced via the two-step pyrolysis of cigarette filters. • Catalytic conversion of triacetin over Al-MCM-41 increased acetic acid yield. • Catalytic pyrolysis of cellulose acetate is improper for acetic acid production. • Selective use of catalyst increased the yield of acetic acid up to 40 %. [ABSTRACT FROM AUTHOR]

Tire wear particle has been considered as one of environmental pollution sources and its sizes are widely ranged from PM2.5 to several hundred micrometer (μm). A bus tire tread is generally composed of NR and BR. In the present work, difference in the rubber compositions of wear particles of a model bus tire tread compound (NR/BR = 80/20) depending on the particle size was investigated by the single particle analysis using Py‐GC/MS. The wear particles were obtained using a laboratory abrasion tester. The wear particles were separated by size using a sieve shaker and those of 212–500, 106–212, and 63–106 μm were used. The rubber composition of each single particle was determined using the principal pyrolysis product ratio of 4‐vinylcyclohexene and dipentene produced from BR and NR, respectively. For the wear particles of 212–500 μm, the rubber compositions were nearly the same to the bulk (the abrasion specimen) and the differences among them were small. But the rubber compositions of the wear particles of below 212 μm were different each other. Some wear particles of 106–212 μm had very high BR composition above 70 wt%. For the wear particles of 63–106 μm, some wear particles had very low BR composition of nearly to zero BR. Difference in the rubber compositions from the bulk tended to be larger by decreasing the wear particle size. The analytical results were explained by the distribution of BR in NR and abrasion position. [ABSTRACT FROM AUTHOR]

Microplastics are now recognized as a persistent and global pollutant. To quantitively measure microplastics in environmental matrices, several techniques are used including new methods using pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS). In the present study, a new extraction method using microwave‐assisted extraction (MAE) combined with Py–GC/MS was developed to extract and quantify a wide range of plastic polymers, and the method was validated using different environmental matrices. This new extraction method was able to extract polyethylene, polystyrene, polypropylene, poly(methyl‐methacrylate) (PMMA), polyvinylchloride (PVC), and polycarbonate in dichloromethane with good recoveries (92.9–119.7%). The limit of detection and limit of quantification (LOQ) of the method ranged from 0.002 to 0.18 µg and from 1.2 to 5.8 µg, respectively. Intra‐ and interday repeatability values with coefficients of variation less than 25% for all polymers were obtained. Method validation also included a spike and recovery using all polymers from clean water, dirty water, and shrimp and salmon fillet samples, with recoveries of 85 to 111, 87 to 138, 81 to 122, and 50 to 151%, respectively. Finally, the method was tested on unspiked wild mussels and bottled water for proof‐of‐concept. Both polyethylene and PVC were detected and quantified in mussels, and polycarbonate and polypropylene were detected below the LOQ. For bottled water, polypropylene, polystyrene, and polycarbonate were all detected below the LOQ. We introduce a method combining MAE and Py–GC/MS as a tool for mass quantification of microplastics. This method can be used as a stand‐alone, or as a complementary method to spectroscopic techniques. Environ Toxicol Chem 2021;40:2733–2741. © 2021 SETAC [ABSTRACT FROM AUTHOR]

[Display omitted] • Estimation of micron-sized microplastics in tea infusion by Raman imaging. • Detection of submicron- and nano-sized microplastics in tea infusion by Py-GC/MS. • Woven tea bags release far fewer microplastics than nonwoven tea bags. • Pre-washing reduced 76–94% micron- and 80–87% submicron-sized microplastic. Microplastics released from plastic-based filter bags during tea brewing have attracted widespread attention. Laser confocal micro-Raman and direct classical least squares were used to identify and estimate micron-sized microplastics. Characteristic peaks from pyrolysis-gas chromatography/mass spectrometry of polyethylene terephthalate, polypropylene, and nylon 6 were selected to construct curves for quantification submicron-sized microplastics. The results showed that microplastics released from tea bags in the tea infusions ranged from 80 to 1288 pieces (micron-sized) and 0 to 63.755 μg (submicron-sized) per filter bag. Nylon 6 woven tea bags released far fewer microplastics than nonwoven filter bags. In particular, a simple strategy of three pre-washes with room temperature water significantly reduced microplastic residues with removal rates of 76 %–94 % (micron-sized) and 80 %–87 % (submicron-sized), respectively. The developed assay can be used for the quantitative evaluation of microplastics in tea infusions, and the pre-washing reduced the risk of human exposure to microplastics during tea consumption. [ABSTRACT FROM AUTHOR]

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To facilitate the reuse and recycling of polyvinyl chloride (PVC) to achieve sustainable development and new industrialization, the composition and mechanism of formation of volatiles during the flash pyrolysis of PVC were studied by thermogravimetry-Fourier transform infrared (TG-FTIR) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). TG and derivative thermogravimetry (DTG) analyses indicated two main degradation stages during flash pyrolysis of PVC, namely dehydrochlorination of PVC and decomposition of dechlorinated-PVC. Simultaneously, the FTIR results revealed that the main functional groups in the pyrolysis process were H–Cl, -C-Cl, C–H, C H, and aromatic groups. The relative content of main volatiles was determined by Py-GC/MS, and decreased in the following order: aromatics > alkenes > hydrogen chloride (HCl) > chlorinated hydrocarbons. Specifically, the relative content of aromatics was as high as 76.790–81.809%, while that of HCl was in the range of 3.016–3.096%. The carbon number distribution and the relative content of main products obtained from the flash pyrolysis of PVC at different final temperatures were also analysed. According to the experimental results, the mechanism of formation of the main volatiles based on free-radical reactions was deduced in detail. Therefore, this study provides further details for deepening the understanding of the PVC pyrolysis process. • The release characteristics of volatiles were consistent with pyrolysis behavior. • HCl, chlorinated hydrocarbons, alkenes, and aromatics were the main volatiles. • Effect of temperature on the distribution of volatile products was revealed. • The formation mechanism of the main volatiles was free-radical reactions. [ABSTRACT FROM AUTHOR]

Waste and low-cost lignocellulosic biomasses are well studied and widely used as raw materials for porous carbon adsorbents. Much less attention is given to the exploration of the potential of marine biomasses, though these materials contain also nitrogen, which—if preserved during the processing—has a beneficial influence on the sorption properties of the porous carbon obtained. Here, we report a multi-technique investigation into the conversion of crab shell to porous carbon adsorbent. Thermogravimetry and pyrolysis-GC/MS studies were used to reveal the thermal degradation of this natural polymer and follow the decomposition process through the identification of the products. Almost 40 various volatile degradation products were distinguished released at 500 °C pyrolysis temperature. Based on the TGA/DTG results, two temperatures, 350 and 500 °C, were selected to obtain pyrolytic samples in macroscopic quantities in order to characterize the morphology and surface chemistry of the solid fraction. More than 50% of the nitrogen atoms were still in the carbonaceous matrix after the 500 °C pyrolysis in the C–N=C, C–NH and 3C–N-type bonds. The ash content < 1% included hydroxylapatite-type crystalline matter. Based on these results, we may conclude that crab shells have a high potential as precursor of nitrogen-containing biochar. [ABSTRACT FROM AUTHOR]

Highlights • Catalytic fast pyrolysis of pretreated pine wood was studied by Py-GC/MS and PCA. • PCA showed how feedstock and pyrolysis conditions affected pyrolysis products. • Temperature and catalyst loading were more important than biomass pretreatment. • Acid-leaching pretreatment slightly lowered the proportion of aromatic products. • The effects of acid-leaching and torrefaction were greatest in non-catalytic pyrolysis. Abstract Non-catalytic and catalytic pyrolysis of pretreated pine wood was conducted using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Biomass pretreatment included acid-leaching, torrefaction, and acid-leaching followed by torrefaction. Forty-five pyrolysis products were identified in the Py-GC/MS chromatograms and their peak area data evaluated by principal component analysis. In non-catalytic pyrolysis, acid-leaching pretreatment enhanced the levels of levoglucosan, while torrefaction pretreatment enhanced the proportion of catechols in the volatile products. Increasing both the temperature and catalyst loading in catalytic pyrolysis promoted the formation of aromatic hydrocarbons. At lower pyrolysis temperatures (450–500 °C), acid-leaching pretreatment resulted in slightly lower proportions of aromatics, while torrefaction pretreatment had the opposite effect. Overall, temperature and catalyst loading were considerably more important factors in catalytic fast pyrolysis of pine wood than biomass pretreatment as studied by Py-GC/MS. [ABSTRACT FROM AUTHOR]

The toxicological research and analysis of synthetic cannabinoids (SCs) have been the focus of scientists. SCs often cause severe acute intoxication after smoking, which may be related to the pyrolysis products formed during the heating process. However, the toxicology studies in vitro and in vivo are hampered by the lack of data on pyrolysis products. Moreover, SCs are diverse and rapidly updated, and the detection of SCs is always a step behind the changes in the illegal market. Here, 44 SCs were analyzed using pyrolysis-gas chromatography/mass spectrometry at 300, 600, and 800 ℃, respectively. The pyrolysis patterns of different SCs under the oxygen-free condition were proposed, based on the pyrolysis products. The shared and characteristic pyrolysis products of 44 SCs were obtained and employed as analytical markers for SCs identification. SCs in one seized e-liquid sample were accurately identified on the basis of the shared and characteristic pyrolysis products. The pyrogram profiles obtained by pyrolyzing SC standards at 600 ℃ were characteristic and reproducible. Therefore, a pyrogram library containing 44 entries for SCs was built through Similarity Evaluation System for Chromatographic Fingerprint of Traditional Chinese Medicine. The pyrogram fingerprinting was used to identify eight unknown SC powders successfully. The results demonstrate the great potential of the pyrolysis pattern of SCs in drug analysis. [Display omitted] • 44 synthetic cannabinoids (SCs) were analyzed using Py-GC/MS. • The pyrolysis patterns of different SCs under the oxygen-free condition were proposed. • Shared and characteristic pyrolysis products are markers for SCs identification. • A pyrogram library containing 44 entries for SCs was established. • The pyrogram fingerprinting was used to identify seized SC powders successfully. [ABSTRACT FROM AUTHOR]

The article presents a study which compared the use of gas chromatography/mass spectrometry (GC/MS) method with React Py-GC/MS method in analyzing the chemical structure of hydrolysis and methanolysis. The variables used include precipitates of the polyamic acid (PAA), tetramethylammonium hydroxide (TMAH) solution, and pyrolyzer. The thermal behavior of polyimides (PI) is described.

Municipal solid wastes (MSW) include a considerable amount of polyvinyl chloride (PVC). How to quickly and harmlessly dispose of the PVC-containing MSW and convert them into a valuable resource is an urgent issue at present. The application of catalysts has yet been proven to be effective in mitigating organic pollutant production. In the present study, a thermogravimetric analyzer (TGA) and pyrolysis-gas chromatography-mass spectrometer (Py-GC/MS) were utilized to investigate the thermodynamic properties, kinetic parameters and pyrolysis characteristics of PVC with different zeolites including HZSM-5 with the Si/Al of 80 and 280, ferrierite, HY and MCM-41 zeolite. It turned out that the introduction of different catalysts with different pore structures and acid site concentrations made different catalytic effects on the cracking mechanism of PVC. Among the five zeolites, MCM-41 decreased temperature at the 50 % conversion to 296 °C, increased weight loss mate at a maximum of 25 %/min and generated fewer PAHs (whose changing amplitude decreased by 94 % in ex-situ catalytic mode in comparison to non-catalytic mode), indicative of its higher catalytic activity in PVC polymer degradation. Under the consideration of maximizing catalytic cracking activity and minimizing secondary pollutants production, non-catalytic dechlorination at approximately 300 °C followed by catalytic degradation in ex-situ mode over mesoporous MCM-41 at higher temperatures was the best recommendation. [Display omitted] • Thermodynamic properties, kinetic parameters and pyrolysis characteristics of PVC were investigated. • The catalytic effects of HZSM-5, HY, ferrierite and MCM-41 were studied. • The catalytic mode had a significant effect on product distribution. • MCM-41 is the most suitable catalyst for the catalytic cracking of sterically challenging PVC polymers. [ABSTRACT FROM AUTHOR]

A method for analysis of Chinese crude propolis was developed by pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) with a vertical microfurnace pyrolyzer. Propolis sample powder about 0.1 mg was pyrolyzed directly at the optimum pyrolytic temperature of 550 °C without any time-consuming pretreatments. 76 compounds were identified on the resulting pyrogram after the pyrolysis of crude propolis, and all the compounds were grouped into 8 categories such as flavonoids, terpenoids, acids, esters, hydrocarbons, phenols and alcohols, aldehydes and ketones, and others. On the basis of peak areas, the relative intensities of 76 peaks were precisely determined with the relative standard deviations (RSDs (%), n = 3) between 1.1 and 14.0%. Furthermore, the compositions of crude propolis samples from different geographical regions in China were analyzed and compared. The contents of 8 categories of compounds in crude propolis samples were different, the predominant categories being flavonoids, esters or hydrocarbons. And also the contents of main bioactivity compounds such as flavonoids and terpenoids were extremely different, and varied largely with 0–54.9% and 0.6–21.6%, respectively. In addition, abundant triterpenoids were identified in Chinese propolis for the first time. It is proved that Py–GC/MS is a simple, rapid and sensitive method for the characterization of the crude propolis. [ABSTRACT FROM AUTHOR]

Fast pyrolysis is a promising technology to promote wood biomass utilization. This thermochemical process produces mainly a liquid bio-oil. Currently, a direct application of bio-oil as fuel is limited due to its poor physicochemical properties. Pressurized Hot Water Treatment (PHWT) has been applied on white spruce and trembling aspen whole wood chips prior to production of pyrolysis oil. The effect of PHWT and the influence of the fast pyrolysis parameters on the bio-oil composition and products distribution were investigated by analytical pyrolysis coupled with gas chromatography/mass spectrometry (Py–GC/MS), it was carried out at two heating rates (100 °C/min and 1000 °C/min) and in temperature ranges from 350 °C to 500 °C for trembling aspen and from 400 °C to 550 °C for white spruce. The pyrolysis products were identified to belong to eleven chemical groups: syringyl derivatives, guaiacyl derivatives, other phenolics, anhydrosugars, low molecular weight acids, fatty acids, furans, pyrans, ketones, aldehydes and alcohols. The results of the analytical pyrolysis indicate that the higher yield is obtained from pretreated than from untreated biomass. The effect of the pretreatment is more important for the 1000 °C/min heating rate than for 100 °C/min. The composition analysis revealed that the higher peak area% of anhydrosugar were obtained from PHWT biomass at 1000 °C/min while the phenols were the major constituents of the pyrolysis products obtained at lower, 100 °C/min heating rate. It is also demonstrated that the acids are still found in pyrolysis products even after pretreatment. The Py–GC/MS results obtained in this study indicate that pretreatment affected the hardwood and softwood in quite different ways. [ABSTRACT FROM AUTHOR]

The painting Ri de Pomme (1988) by American artist Julian Schnabel was recently subjected to an extensive and disputed restoration with polyvinyl acetate (PVAc) paints. To characterize and locate on the painting the materials used in the original and in the repainted areas, we employed several spectroscopic and chromatographic techniques. Fibre Optics Reflectance Spectroscopy (FORS), Micro-Raman, Pyrolysis-Gas Chromatography/Mass Spectrometry (Py- GC/MS) and Gas Chromatography/Mass Spectrometry (GC/MS) were used. The original and restoration paint layers were differentiated by a preliminary FORS survey. The pigments were studied with Micro-Raman and the oil binder was characterized by GC/MS. Moreover, the support of the painting, a weathered tarpaulin, was characterized by Py-GC/MS. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new quantification method for synthetic microfibers was proposed using Py-GC/MS. • Wastewater emitted from textile laundry was filtered using 45 and 26 μm filters. • Synthetic microfibers were selectively extracted by the use of hexafluoroisopropanol. • Quantification curves for PET, nylon-6, and PAN had the good linearity (R2 > 0.994). • Blended textiles emitted the larger amount of microfibers than single textiles. This paper reports a new qualification and quantification method for synthetic microfibers (MFs), polyethylene terephthalate (PET), nylon-6 (N-6), and polyacrylonitrile (PAN), emitted from textiles during the laundering process by applying a sequential process involving the filtration of laundry wastewater, solvent extraction with hexafluoroisopropanol (HFIP), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). After filtering the textile laundry wastewater, selective sampling of synthetic MFs excluding non-target matrices and natural fibers was achieved by extracting the filtered samples with HFIP. MF recovery for HFIP extraction by Py-GC/MS analysis was 91.4 %, 98.5 %, and 98.8 % for PET, N-6, and PAN, respectively. The calibration curves obtained from Py-GC/MS analysis for PET, N-6, and PAN in the weight range between 1 and 50 μg showed good linearity (R2 > 0.994). The detection and quantification limits were lower than 0.2 μg and 0.6 μg for all polymers. The quantification results for the MFs extracted from the textile made from a single filer indicated that PET, N-6, and PAN textile produced 481, 111, and 329 mg of MFs/kg textile, respectively. Compared to the single textile (PET), the blended textiles produced larger amounts of MPs, 961 mg/kg for PET/cotton and 680 mg/kg for PET/wool blended textiles, suggesting the easier formation of MFs from blended textiles during textile laundering. [ABSTRACT FROM AUTHOR]

• Pyrolysis product distribution was assessed based on organic and inorganic content. • Evolution profiles of carbohydrate and lignin products were determined by TG/MS. • Phenol evolution from ester bonded lignin units was monitored by TG/MS above 220 °C. • Depolymerization of both hemicellulose and cellulose was hindered by potassium. • EFB supposed to be treated separately from KS and MF during thermal utilization. The palm oil industry produces large amounts of biomass by-products, such as palm empty fruit bunch (EFB), mesocarp fiber (MF), and kernel shell (KS). The thermal behavior and decomposition of the oil palm biomass wastes have been studied by thermogravimetry/mass spectrometry (TG/MS) and pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS). The determination of biopolymer and inorganic composition facilitated the interpretation of the thermal decomposition results. It was established that the chemical compositions of KS and MF were similar, while EFB contained significantly higher amount of cellulose and potassium, and decomposed in a narrower temperature range. In addition to the thermogravimetric curves (TG and DTG), the product distribution of pyrolyzates also reflected the compositional differences. Py-GC/MS and TG/MS experiments showed that the increasing potassium content of the samples reduced the intensity of 4-hydroxy-5,6-dihydro-2 H -pyran-2-one, which is formed via depolymerization and dehydration of xylan units. Consequently, these experiments proved that beside cellulose, the depolymerization of hemicellulose was also hindered, while the dehydration, fragmentation, and charring reactions were catalyzed by potassium. Additionally, the evolution of the characteristic cellulose and lignin products shifted to lower temperatures. The most dominant aromatic pyrolysis product was phenol from each sample, which formed to a large extent from the abundant 4-hydroxybenzoate (4Hb) lignin subunits by scission and decarboxylation. KS also produced 4-hydroxybenzoic acid in significant amounts during pyrolysis at 450 °C confirming the presence of 4Hb subunits in lignin. The evolution of phenol started at 220 °C from the 4Hb moieties, and ended at about 600 °C from the residual phenolic units, while the release of guaiacol, vinylguaiacol, and syringol occurred between 300 and 450 °C as monitored by TG/MS. Some characteristic carbohydrate products were attributed to either hemicellulose or cellulose degradation based on the evolution profiles of KS and MF with separated carbohydrate decomposition steps. The comparison of the oil palm biomass wastes showed that EFB is supposed to be treated separately from KS and MF during the utilization process due to the different thermal behavior and composition. [ABSTRACT FROM AUTHOR]

• Ammonium and nitrate fertilization had opposite effects on SOC contents. • Nitrate fertilization sequestrated more SOC through increasing plant inputs. • Ammonium treatment shifted microbial community structure from bacteria to fungi. • Py-GC/MS is a powerful technique to investigate the chemical structure of SOM. Elevated nitrogen (N) deposition plays a critical role in soil organic matter (SOM) transformation, but the responses of the quantity and quality of SOM to ammonium and nitrate fertilization remain unclear. In this work, a 6-year field experiment amended with ammonium chloride (NH 4 Cl) and potassium nitrate (KNO 3) fertilizers at four rates of 0, 10, 20, and 40 kg N ha−1 yr−1 was conducted in a boreal forest. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) analysis and elemental analysis were used to investigate the chemical composition and soil organic carbon (SOC) contents in bulk soils and two density fractions (light fraction < 1.70 g cm−3 and heavy fraction > 1.70 g cm−3). Soil microbial community composition was determined based on phospholipid fatty acids (PLFAs) analysis. Results showed that the SOC contents in the organic and mineral layers under nitrate addition were significantly increased by 27–87%. By contrast, ammonium addition significantly decreased the SOC contents in the organic layer by 28–54%. Nitrate addition increased relative proportions of acetic acid in the light fraction and toluene in bulk soil, but decreased relative abundance of phenol in bulk soil, indicating that more plant-derived input contributed to the increase of SOC. Contrastingly, ammonium addition increased the proportions of benzene in bulk soil and pyrrole as well as the mineralization index (pyrrole/phenol) in the heavy fraction, suggesting more advanced mineralization degree of SOM. Moreover, ammonium addition altered microbial community structure with a higher ratio of fungi/bacteria (F/B) while nitrate addition had little effect on soil microbial community. Overall, our findings highlight the contrasting roles of ammonium and nitrate in SOM dynamics, which should be distinguished to accurately predict the responses of SOC sequestration to N deposition especially in N-limited boreal forests. [ABSTRACT FROM AUTHOR]

• Dry and pre-wetted Er:YAG laser irradiation tests on the varnish layer of a painting. • Evaluation via gloss-related factors generated from colourimetric data. • Evaluation via spectral clusterisation maps generated from multispectral imaging data. • Py-GC/MS and ATR/FT-IR analysis of the varnish before and after Er:YAG irradiation. This paper aims to evaluate the Er:YAG laser efficacy to safely thin a varnish on a modern 19th century oil painting. Tests were carried out under single and multiple laser scans directly on the surface (dry) or after pre-wetting with deionised water (DIW) and a non-ionic surfactant (Tween 20), fluence ranges of 0.56–2.40 J/cm2 and 100 μsec pulse duration. Microscope glass coverslips were placed on the painting surface during irradiation to collect the condensed resin fragments that were extracted from the varnished surfaces. Spectral clusterisation maps of Multispectral Imaging (MSI) data of the irradiated surface supported the evaluation of the procedure. Further evaluation was performed by stereomicroscopy and colourimetry. Fourier Transform Infrared spectroscopy (FT-IR) and Pyrolysis Gas Chromatography / Mass Spectrometry (Py-GC/MS) analysis indicated that the varnish resin was dammar. The collected resin fragments were analysed by FT-IR. The results showed that the resin did not degrade even at the highest level of fluence employed, thereby allowing a subsequent analytical evaluation. [ABSTRACT FROM AUTHOR]

• Unexpected high methylmercury levels occurred in wetland soils along the YTR in Tibet. • Topsoils had more THg but less MeHg contents than subsoils. • Lignin and phenol moieties were and positively related to THg in topsoils. • THg contents were closely related to plant-derived organic compounds. • Molecular compositions of SOM are critical to MeHg in wetland soils along the YTR. Deciphering the role of soil organic matter on methylmercury production in wetlands is an important environmental topic in Tibet, where is the province with the largest number of international rivers, including the Yarlung Tsangbo River. In this study, total mercury (THg) and methylmercury (MeHg) contents in soils from wetlands along the YTR were detected, and roles of the molecular composition of soil organic carbon (SOC) in the formation of MeHg were explained in detail by pyrolysis–gas chromatography/mass spectrometry technology (Py-GC/MS). On average, THg and MeHg contents were 62.9 ng/g and 5.88 ng/g, respectively. About 12.6% of total Hg was in the form of MeHg. Unexpected high methylmercury levels occurred in wetland soils along the YTR. The topsoils (0–20 cm) had more THg but less MeHg contents than those in subsoils (20–48 cm). The proportion of MeHg to THg (RHg) was higher in subsoils than in topsoils independent of wetland types. Correlations between THg, MeHg, and SOC were weak in topsoils but strong in subsoils. Lignin and phenol moieties of SOC pyrolysis products were significantly and positively related to THg in topsoils, while positive or negative correlations were found between THg, MeHg, and pyrolysis products of SOC in subsoils at p < 0.05 level. C/N ratios were negatively related to RHg to a significant level in both topsoils and subsoils. Hg/C ratios correlated negatively with C/N ratios in both topsoils and subsoils at the 0.001-level, and larger coefficients in subsoils confirmed that older and high decomposed soil organic matter generally have high levels of Hg. Principle component analysis indicated that THg contents were closely related to plant-derived organic compounds, and MeHg contents were closely related to phytoplankton-derived organic compounds. Our findings suggested that molecular compositions of soil organic matter are critical to MeHg presentence in wetland soils along the YTR. [ABSTRACT FROM AUTHOR]

• The pyrolysis behavior of cattle manure was analyzed by PIMS and GCMS. • Products mainly contained ketones, phenols and N-heterocyclic compounds. • Maillard reaction had great effect on the pyrolysis process of cattle manure. • A predicted generation pathway of major products was proposed. Cattle manure is a kind of abundant agriculture waste but potential renewable resource to be converted into fuel by pyrolysis. The pyrolysis behavior of cattle manure was analyzed by three methods in this work: thermogravimetric analyzer (TG), pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and pyrolysis photoionization time-of-flight mass spectrometry (Py–PI–TOFMS). The pyrolysis process of cattle manure included four stages, dehydration stage, lignocellulose decomposition stage, lignin and protein decomposition stage, char and mineral matter decomposition stage. The products were mainly classified into six groups: ketones, aldehydes, phenolic compounds, acids, hydrocarbons and N-containing compounds. Based on the time-evolved profiles and temperature-programmed profiles, the characteristics of these major products were analyzed and discussed. Maillard reaction has great effects on the pyrolysis process of cattle manure because cellulose can easily react with protein to produce abundant Amadori products and then generate cyclopentanes and furanmethanol. In addition, some Amadori products and amino acids can also be cyclized to generate N-heterocycle compounds like pyrroles and pyrazines. The decomposition of lignin basic units with more methoxy groups require higher reaction temperature, and the removal of hydroxy and methoxy group on phenols mainly occurred at around 350 °C. Furthermore, primary decomposition pathways of cattle manure were also proposed and discussed. [ABSTRACT FROM AUTHOR]