Pyrolysis Gas Chromatography Research Articles

The potential of White Rot fungi from Indonesia for biodegradation of expanded polystyrene

Expanded polystyrene (EPS) is a polymer known for its remarkable resistance to degradation. Despite several studies conducted on polymer degradation, there is still limited information about the use of White Rot fungi (WRF) to degrade EPS. Our study aims to explore the potential of WRF, which are known to have several isozymes of laccase, a powerful oxidoreductases that potentially could aid in EPS biodegradation. We evaluated the results based on two parameters: (1) morphological damage observed through gravimetry and Scanning Electron Microscope (SEM), and (2) physical, chemical, and mechanical properties of degraded EPS characterized using Universal Attenuated Total Reflection-Fourier Transform Infrared (UATR-FTIR), Thermogravimetric (TGA), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), and Pyrolysis Gas Chromatography Mass Spectrometry (Py-GCMS). Our findings revealed that Phelinus noxius BRB 11 and Leiotrametes menziesii BRB 73 were able to resist 10.000 ppm EPS and demonstrated growth rates of 1.86 and 1.22 cm/day, respectively, causing 16 and 1% EPS weight loss after 30 days of incubation. UATR-FTIR analysis showed significant changes in the transmittance value of treated EPS. Phelinus noxius BRB 11 exhibited the highest crystallinity and the lowest styrene percentage area compared to Leiotrametes menziesii BRB 73. Based on all parameters in this study, our results suggest that Phelinus noxius BRB 11 has the best potential as a polymer degradation agent, particularly for EPS.

Kinetic, products and shrinkage for the pyrolysis of flax fibers

Biomass pyrolysis is a thermochemical process used for renewable products and energies. However, there are still issues that need to be addressed for process modeling and optimization. This study focuses on the relationship between heating rate, shrinkage, and products from flax fibers using thermogravimetric analysis (TGA), microscopic observation, and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). TGA confirms sequential evaporation of water then decomposition of hemicellulose, cellulose, and lignin. Observations from the micro-reactor show that flax fibers undergo shrinkage within the temperature range of 335–370 ∘C, depending on the heating rate. Pyrolysis products were analyzed using Py-GC/MS at four different final temperatures from 350 to 500 ∘C, revealing the presence of anhydrosugars, furans, ketones, phenols, esters, alcohols, aldehydes, and acids. The results indicate a correlation between temperature and the increase in furans and ketones. The analysis suggests that furans and ketones are associated with shrinkage.

Characterization of lamp oil residues from Tangchaodun Site, Xinjiang, northwest China during the 8th−13th centuries CE

Lamp illuminants reflect how ancient people exploited natural resources, such as animal fat, plant oil and mineral oil. Besides, the commercial trade of lamp oil, including olive oil, represented economic exchange. In addition, oil lamps were often used in religious practices to glorify deities and illuminate grand halls. Although many ancient lamps have been found in China, there are few scientific reports regarding ancient lamp illuminants. In this study, chemical analysis including FTIR (Fourier Transform Infrared Spectroscopy), Py-GC/MS (Pyrolysis Gas Chromatography-Mass Spectrometry), GC–MS (Gas Chromatography-Mass Spectrometry), and GC-C-IRMS (Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry) was applied to characterize black residues remaining on the surface of pottery lamps from the Tangchaodun site, northwest China, from the 8th to 13th centuries CE. The results show that the black residues are soot, and both ruminant adipose fat and plant oil were used as the primary fuel. These lamps share similar morphology and utilize similar combustibles, implying that the production of both lamps and oil may have undergone convergent evolution driven by aesthetic preferences. Furthermore, the ruminant animals mainly fed on C4 plants, indicating that these animals were raised in pens and millet agriculture was practiced in this region.

Determination of lignin composition in compression wood-like reaction wood of angiosperm Gardenia jasminoides by pyrolysis–gas chromatography–mass spectrometry

Abstract Using pyrolysis–gas chromatography–mass spectrometry, the lignin composition was analysed in normal and reaction wood samples grown at three stem inclination angles in Gardenia jasminoides, which forms compression wood-like reaction wood. Lignin content among the samples was not significantly different. However, the reaction wood samples with larger stem inclination angles showed a lower syringyl/guaiacyl ratio. In conclusion, the degree of inclination affected the lignin composition in G. jasminoides reaction wood, and qualitative changes in lignin might be necessary to mechanically support the stems in this species.

Characterization and identification of an archaeological “lacquer” pipe

A pipe with red coating on the surface was excavated from an archaeological site in Sweden, which is supposed to be a lacquer ware imported from China due to the admiration and pursue of lacquer wares from Asia by Europeans during sixteenth to eighteenth centuries. However, materials such as shellac and resins were often used to imitate lacquer during that time in Europe. To determine whether the pipe was Chinese lacquer ware or not, attenuated total reflection of fourier transform infrared spectroscopy (ATR-FTIR), thermally-assisted hydrolysis and methylation pyrolysis gas chromatography-mass spectrometry (THM-Py-GC/MS) were conducted. The detection of significant amount of aleuritic acid, laccijalaric acid, laccishellolic acid, shellolic acid and jalaric acid represents that shellac is the main material used for the pipe coating rather than Chinese lacquer. Long chain fatty alcohols were found in the sample, indicating that the shellac is un-dewaxed. In addition, pine resin and turpentine were also found as additives in the pipe coating. Furthermore, pigments in the coating were determined as cinnabar and carbon black by scanning electron microscopy with element energy dispersive spectroscopy (SEM–EDS) and Raman spectroscopy. The results could definitely support the conservation of the pipe, and also provide the evidence of the cultural exchange between Europe and Asia.

A Study on the Materials Used in Ancient Wooden Architectural Paintings at DaZhong Gate in Confucius Temple, Qufu, Shandong, China.

This study analyzes the pigments and binders used in the painted wooden structure of DaZhong Gate in the Confucius Temple in Qufu, Shandong Province, China. Five samples were collected from the building and analyzed using techniques such as polarized light microscopy (PLM), energy-dispersive X-ray spectroscopy (EDX), micro-Raman spectroscopy (m-RS), and Fourier-transform infrared spectroscopy (FT-IR). The findings reveal that the red, yellow, green, and blue pigments are identified as lead red, lead chromate yellow, emerald green, and ultramarine, respectively. The white pigment is determined to be a combination of chalk and lead white or anglesite. Considering the production period of the yellow and green pigments, it is inferred that architectural paintings underwent restoration or repainting during the late Qing Dynasty. The analysis of the binder in the pigment using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) reveals that the binder employed is a protein-based glue. Additionally, the detected presence of Heat-bodied tung oil suggests a potential connection to traditional Chinese painting techniques on wooden surfaces. This discovery not only contributes to the historical research of the Confucius Temple but also provides crucial data for the conservation and restoration efforts of this culturally significant heritage site.

Polymer-type flame retardants based on a DOPO derivative for improving the flame retardancy of polyamide 6: Preparation, properties and flame retardancy mode of action

A polymer-type flame retardant (PFR) based on a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivative was synthesised here to improve the flame retardancy of polyamide 6 (PA6). The chemical structure and thermal property of the PFR were characterised by Fourier-transform infrared (FTIR) spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography (GPC), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The PFR and PA6 were melt-blended to obtain a flame-retardant polyamide 6 (FRPA6). Its thermal property, mechanical property and flame retardancy were characterised via TGA, DSC and tensile, impact, vertical burning and limiting oxygen index (LOI) tests. Its flame-retardant mode of action was analysed by scanning electron microscopy, FTIR spectroscopy, cone calorimetry and pyrolysis-gas chromatography-mass spectrometry. The FRPA6 with a phosphorus content of 3000 ppm passed the UL-94 V-0 rating, and the LOI of the FRPA6 with a phosphorous content of 5000 ppm reached 28.8 %. Compared with pure PA6, the peak heat release rate, total heat release and effective heat of FRPA6–5000 were reduced by 35.4 %, 21.9 % and 26.5 %, respectively. These results indicate that the flame-retardant mode of action of PFR mainly involved the quenching effect of phosphorus-containing radicals in the gas phase.

Insight into natural ageing of historic baltic amber objects by untargeted metabolomics approach

Cherished amber relics have undergone long-period burial environments carrying several ageing deterioration characteristics, such as crazing, discolouration, and decreased hardness, which makes amber artefacts fragile. Ageing is inevitable for amber exposed to air, emphasising the need for a suitable preservation environment based on the ageing mechanism. However, related research, specifically on the transformed compositions and structures of archaeological amber, has been limited due to complexities in deciphering the intricate components. In this research, attenuated total reflection Fourier transform infrared (ATR-FTIR), X-ray fluorescence (XRF), inductively coupled plasma optical emission spectroscopy (ICP-OES) and pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) were applied on geological and archaeological Baltic amber to find the ageing pathways. An untargeted metabolomics analysis developed for the linear modelling of molecular features data was utilised in combination with Py-GC/MS results, and statistically significant variations provided ten increased and ten decreased ageing markers. We propose an ageing mechanism for the succinite molecular structure, which involves oxidation of the polylabdanoid and hydrolysis of the esterification cross-link structure between succinic acid and labdanoid. Simultaneously, monoterpenes were released from the amber structure. Our untargeted Py-GC/MS metabolomics approach offers a groundbreaking and more systematic method for investigating the ageing mechanism of multi-component organic polymers in archaeological artefacts.

A Multi-Method Analysis of a Color Painting on Ancient Architecture from Anyuan Temple in Chengde, China

Anyuan Temple, constructed in the 29th year of the Qing Dynasty (1764), serves as a repository of numerous Sanskrit inscriptions and Hexi color paintings from the Qing era. Among its collections, the green Tara Buddha statue, exquisitely carved from wood, is recognized as a national first-class cultural relic. This edifice is instrumental in advancing our comprehension of painting artistry in royal temples. The current research focused on the pigments and binders utilized in the color paintings within Anyuan Temple, located in Chengde. An investigative process entailed collecting four samples from the paintings adorning the temple’s beams. These samples underwent comprehensive analysis using a variety of techniques, such as Scanning Electron Microscopy and Energy-Dispersive Spectrometry (EDS), Micro Raman Spectroscopy (m-RS), and X-ray Diffraction (XRD). The examination revealed that the paintings comprised pigments of lead white, cinnabar, malachite, and azurite, corresponding to the colors white, red, green, and blue, respectively. The enduring stability and aesthetic appeal of these pigments suggest their suitability for use in future conservation efforts. Additionally, Pyrolysis Gas Chromatography/Mass Spectrometry (Py-GC/MS) analysis identified animal glue as the binding agent in the wood component paintings. These insights are pivotal for the forthcoming restoration endeavors of Anyuan Temple, offering essential guidance in selecting the appropriate materials for restoration.

Synergistic effects of mechanochemical activation and selective O-alkylation on the chemical structure and gaseous products evolution during coal flash pyrolysis

Mechanochemical activation offers significant advantages in enhancing the pore structure and active sites of materials, while selective O-alkylation boosts both the homogeneous and heterogeneous reactivity of coal. In this work, mechanochemical activation and selective O-alkylation are synergistically applied to modify pulverized coal. The evolution of the chemical structure was thoroughly characterized using ultimate analysis, Fourier-transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR). Pyrolysis gas chromatography-mass spectrometry (PY-GC-MS) was utilized to investigate the release of crucial gaseous products during the pyrolysis. Additionally, this study focuses on the synergistic effects of mechanochemistry and selective O-alkylation on the chemical structure and pyrolysis characteristics. The results reveal that alkylation boosts the formation of C-O bonds and aliphatic carbon while reducing the presence of aromatic carbon. Moreover, by disrupting intermolecular forces, alkylation induces the fragmentation of expansive aromatic layers into smaller aromatic fragments, thereby generating additional structural defects. Furthermore, the electron transfer process facilitates the conversion of aromatic carbon into aliphatic forms through ring-opening reactions. On the other hand, incorporating alkyl functional groups and initiating ring-opening reactions of aromatic carbons lead to a rise in aliphatic hydrocarbons during the pyrolysis of alkylated coal. However, intensified mechanochemical action hinders the production of aliphatic hydrocarbons. Additionally, during alkylation, the creation of esters and ethers with elevated thermal stability delays the release of oxygen-containing gas products. The findings propose a new pretreatment method for coal utilization, promoting the development of new low-NOx combustion technology.

Comparative microplastic analysis in urban waters using μ-FTIR and Py-GC-MS: A case study in Amsterdam

The contamination of freshwater with microplastics (MPs) has been established globally. While the analysis of MPs has predominantly involved spectroscopic methods for revealing particle numbers, the potential of employing spectroscopy for mass estimation has been underutilized. Consequently, there is a need to enhance our understanding of the mass loads of MPs and ensure the complementarity and comparability of various techniques for accurate quantification. This study presents the first comparative results on urban water samples using micro Fourier-transform infrared (μ-FTIR) imaging and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) to identify and quantify MPs in both particle numbers and mass concentration. Two sampling campaigns in summer and winter were conducted at 11 locations within the Amsterdam canal network. An advanced in-situ volume-reducing sampling pump was employed to collect MPs from the surface water within the size fraction of 10–300 μm. The analysis revealed MP concentrations within the range of 16–107 MP/m3, estimated to be 2.0–789 μg/m3 by μ-FTIR imaging and 8.5–754 μg/m3 by Py-GC-MS. The results of the two analysis techniques showed good comparability in terms of the general trends of MP abundances, with variations in polymer compositions due to the inherent inter-methodological differences. Elevated MP concentrations were observed in the city center compared to the suburban areas. In addition, seasonal differences in MP abundances were noted at the locations with high human activity.

Sources of organic matter elucidated through Pyr-CG-MS, and relation to basin scale events in the Pimienta Formation (Central Mexico)

The study of organic matter is essential for understanding the sedimentary and diagenetic processes that have occurred in a certain area. Sediments rich in organic matter with a vocation for producing hydrocarbons are of particular importance. Studies of organic matter in these environments help not only to determine their potential as hydrocarbon generators, but also contribute to the understanding of the processes that have occurred in the basin over time. In this study, the use of pyrolysis-gas chromatography-mass spectrometry (Pyr-GC-MS) is proposed to analyse the diversity of organic molecules contained in the sediments of the Pimienta Formation. This technique is versatile and, although destructive, allows rapid analysis of organic matter, in addition to the minimal quantities required for the study. Pyr-GC-MS allows functional groups to be determined; in this study 34 different moieties were identified. The use of this technique is perfectly complemented by Rock-Eval-pyrolysis and fluid inclusion studies, which allows greater detail of the origin of the molecules. The results of the Rock Eval Pyrolysis suggested that there were two types of kerogen: continental (Type III) and marine (Type II)]. Some samples contained organic matter of continental origin , while others contained organic matter of marine origin. Analysis of fluid inclusions suggested sedimentary-diagenetic and meteoric sources for fluids, as well as different types of interaction between them and the surrounding rocks.

The nitrogen transformation behavior based on the pyrolysis products of wheat straw

In order to provide basic design parameters for the industrial pyrolysis process, the transformation behavior of nitrogen was investigated using wheat straw as raw material. The distributions of nitrogen in pyrolysis char, oil and gas were obtained and the nitrogenous components in the products were analyzed systematically by X-ray photoelectron spectroscopy (XPS), pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and thermogravimetric-Fourier transform infrared spectrometry (TG-FTIR). The nitrogen distribution ranges of the pyrolysis char, oil and gas were 37.34% − 54.82%, 32.87% − 40.94% and 10.20% − 28.83%, respectively. More nitrogen was retained in char at lower pyrolysis temperature and the nitrogen distribution of oil was from rise to decline with increasing temperature. The most abundant N-containing compounds in three phase products were pyrrole-N, amines and HCN, respectively. In addition, the transformation mechanism of nitrogen from wheat straw to pyrolysis products was concluded.

Analytical Pyrolysis of Soluble Bio-Tar from Steam Pretreatment of Bamboo by Using TG-FTIR and Py-GC/MS.

Steam pretreatment at high temperatures enables fresh bamboo to possess antifungal and antiseptic properties. The process produces a large amount of wastewater that urgently needs to be recycled. Soluble bio-tars derived from wastewater under low-temperature (LTS-tar) and high-temperature (HTS-tar) steam pretreatments of moso bamboo were studied with a thermogravimetric analyzer coupled with Fourier transform infrared spectroscopy (TG-FTIR) and pyrolysis-gas-chromatography/mass spectrometry (Py-GC/MS). Thermogravimetric analysis showed that in the three stages of the thermal decomposition process, the final residue of the bamboo and HTS-tar had two main peaks of 0.88 wt% and 6.85 wt%. The LTS-tar had much more complicated thermal decomposition behavior, with six steps and a high residue yield of 23.86 wt%. A large quantity of CH4 was observed at the maximum mass loss rates of the bamboo and bio-tars. Acids, aldehydes, ketones, esters, and phenolic compounds were found in the pyrolysis products of the bamboo and soluble bio-tars. Both bio-tars contained carbohydrates and lignin fragments, but the LTS-tar under mild steam conditions had more saccharides and was much more sensitive to temperature. The lignin in the bamboo degraded under harsh steam conditions, resulting in high aromatic and polymeric features for the HTS-tar. The significant differences between LTS-tar and HTS-tar require different techniques to achieve the resource utilization of wastewater in the bamboo industry.

Synthesis and pyrolysis of polyacrylate-supported flavor precursors

Herein we present a novel ‘polymerization strategy’ aimed at synthesizing flavor precursors, with a focus on enhancing their thermal stability and release properties. Three volatile flavors, menthol, methyl cyclopentenolone, and ethyl maltol, are reacted with acryloyl chloride to produce corresponding vinyl monomers. These monomers undergo radical polymerization to form homopolymers (P1−P3). To improve solubility in alcohol solvents, a hydrophilic oligoethylene glycol monomer is introduced, copolymerized with the flavor containing monomers, resulting in copolymers (P4−P6). An important advantage of these polymers lies in their significantly enhanced thermal stability, exhibiting an increase of approximately 100 to 200 °°C compared to small molecular flavors. Furthermore, our methodology enables efficient release of the target flavors upon heating, as evidenced by online analyses of volatiles from pyrolysis using fixed-bed reactor combined with single photoionization mass spectrometry (FBR-SPIMS) and pyrolysis-gas chromatography-mass spectrometry (Py-GC–MS). This work represents a practical and innovative approach to improving the thermal stability of volatile flavors and elevating their release temperature, offering promising applications in high-temperature food processing and tobacco industries.

Arone-containing cyclomatrix-type polyphosphazene hybrid microspheres for epoxy resin: Enhancing fire safety and mechanical properties

Arone-containing cyclomatrix-type polyphosphazene hybrid microspheres (PZK) were synthesized to enhance both the fire safety and mechanical performance of epoxy resin (EP). The chemical structure and micro-morphology of PZK were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy, and X-ray photoelectron spectroscopy. Subsequently, PZK was employed in fabricating EP thermosets. Thermal properties of the PZK modified EP thermosets were comprehensively assessed through thermalgravimetric analysis (TGA) and dynamic mechanical analysis. The results indicate that PZK endowed EP with enhanced char yield and storage modulus, attributed to its exceptional thermal stability and distinctive microsphere structure. Additionally, with only a 1.5% loading of PZK, EP achieved a UL-94 V-1 rating during vertical flame testing, accompanied by an increased limiting oxygen index of 28.3%. Additional analysis with a cone calorimeter demonstrated that the addition of PZK markedly reduced the peak heat release rate, total heat release, fire growth rate, and total smoke production of EP, indicating notable efficacy in suppressing heat and smoke release. Char residue and pyrolysis products were analyzed using SEM, TG-FTIR, and pyrolysis gas chromatography-mass spectrometry, revealing that PZK effectively inhibits the release of combustible gases from EP during thermal decomposition. The expected generation of Ph—O• radicals from arone units in PZK suggested a gaseous free radical trapping mechanism. The phosphazene framework played a crucial role in forming condensed-phase char due to its exceptional thermal stability. Consequently, PZK exhibited a typical biphasic flame-retardant mechanism for EP. Notably, the study observed that the introduction of PZK simultaneously enhances the tensile strength, flexural strength, and modulus of EP, with a particularly significant improvement observed in impact strength. This research expands the scope of investigation into the preparation and flame-retardant application of cyclomatrix-type polyphosphazene hybrid microspheres in polymers.

Pyrolysis of plasticized films based on soy protein, denatured by different substances

Polymer films based on soy protein isolate (SPI) were obtained using the thermo-pressing method. Plasticizers and denaturing agents were added to ensure better the film-forming properties and reduce the fragility of the resulting materials. Glycerol, sorbitol and their mixture were used for plasticization, while solutions of alkali (potassium hydroxide), surfactants of natural origin (sodium coco sulfate) and reducing agent (sodium sulfite) were used for denaturation. By combining different types of plasticization and denaturation, a series of samples were obtained and compared with a sample based on raw soy protein. In addition to the obvious differences in the appearance of the films, the processes of their thermal degradation, studied by pyrolysis mass spectrometry, also differed significantly. In fact, unprocessed soy protein has the highest thermal stability with the temperature of the most intensive decomposition equal to 270 °С, which can decrease to 200 °С under the conditions of denaturation and plasticization. Despite the increase in the number of film components, the amount of volatile decomposition products decreases (from 86 to 32), as well as the molecular weight of the heaviest of them (from 169 to 74). This is a sign of a change in the mechanism of soy protein degradation due to denaturation and plasticization caused by transformations in its supramolecular structure, such as unfolding and extension of macrochains with increased availability of functional groups. The pyrolytic behavior of some protein samples plasticized with sorbitol is closest to that of untreated soy protein, which may indicate a lower plasticizing efficiency of sorbitol with longer molecules than glycerol. The interpretation of the recorded mass spectra of the volatile pyrolysis products showed that the thermal degradation of protein materials is dominated by processes such as decarboxylation, dehydration, deamination and decarbonylation, while in the presence of plasticizers the splitting of their own molecules also becomes dominant. The characteristic mass spectra of protein films denatured by surfactants also contain ionic fragments of relatively high molecular weight, probably derived from sodium coco sulfate molecules.

Multimodal detection and analysis of microplastics in human thrombi from multiple anatomically distinct sites

Microplastic (MP) pollution has emerged as a significant environmental concern worldwide. While extensive research has focused on their presence in marine organisms and ecosystems, their potential impact on human health, particularly on the circulatory system, remains understudied. This project aimed to identify and quantify the mass concentrations, polymer types, and physical properties of MPs in human thrombi surgically retrieved from both arterial and venous systems at three anatomically distinct sites, namely, cerebral arteries in the brain, coronary arteries in the heart, and deep veins in the lower extremities. Furthermore, this study aimed to investigate the potential association between the levels of MPs and disease severity. Thrombus samples were collected from 30 patients who underwent thrombectomy procedures due to ischaemic stroke (IS), myocardial infarction (MI), or deep vein thrombosis (DVT). Pyrolysis-gas chromatography mass spectrometry (Py-GC/MS) was employed to identify and quantify the mass concentrations of the MPs. Laser direct infrared (LDIR) spectroscopy and scanning electron microscopy (SEM) were used to analyse the physical properties of the MPs. Demographic and clinical information were also examined. A rigorous quality control system was used to eliminate potential environmental contamination. MPs were detected by Py-GC/MS in 80% (24/30) of the thrombi obtained from patients with IS, MI, or DVT, with median concentrations of 61.75μg/g, 141.80μg/g, and 69.62μg/g, respectively. Among the 10 target types of MP polymers, polyamide 66 (PA66), polyvinyl chloride (PVC), and polyethylene (PE) were identified. Further analyses suggested that higher concentrations of MPs may be associated with greater disease severity (adjusted β=7.72, 95% CI: 2.01-13.43, p<0.05). The level of D-dimer in the MP-detected group was significantly higher than that in the MP-undetected group (8.3±1.5μg/L vs 6.6±0.5μg/L, p<0.001). Additionally, LDIR analysis showed that PE was dominant among the 15 types of identified MPs, accounting for 53.6% of all MPs, with a mean diameter of 35.6μm. The shapes of the polymers detected using LDIR and SEM were found to be heterogeneous. This study presents both qualitative and quantitative evidence of the presence of MPs, and their mass concentrations, polymer types, and physical properties in thrombotic diseases through the use of multimodal detection methods. Higher concentrations of MPs may be associated with increased disease severity. Future research with a larger sample size is urgently needed to identify the sources of exposure and validate the observed trends in the study. This study was funded by the SUMC Scientific Research Initiation Grant (SRIG, No. 009-510858038), Postdoctoral Research Initiation Grant (No. 202205230031-3), and the 2020 Li Ka Shing Foundation Cross-Disciplinary Research Grant (No. 2020LKSFG02C).

Comparative Evaluation of Analytical Techniques for Quantifying and Characterizing Polyethylene Microplastics in Farmland Soil Samples

The presence of microplastics in soil has become a significant global concern, posing a threat to environmental, agricultural, and human health. However, the use of various detection methods has led to significant discrepancies in the statistics reported for the abundance of soil microplastics across the available literature, resulting in poor comparability across the available literature. Studies have shown that plastic film residue is among the main primary sources of microplastics in farmland soils. Therefore, we manufactured and selected polyethylene microplastics (PE-MPs) from plastic film and combined them with soil samples after density separation treatment, forming a spiked test soil sample, which was subjected to density separation and extraction using a ZnCl2 solution. The experiment used visual inspection by stereo microscopy, micro-Fourier transform infrared spectroscopy, micro-Raman spectrometry, laser direct infrared imaging, and pyrolysis-gas chromatography–mass spectroscopy for the quantitative analysis of spiked soil. This study systematically assessed and compared these five common soil microplastic detection methods. The results revealed different quantitative detection accuracies across various particle size ranges. Micro-Fourier transform infrared spectroscopy showed a broader applicable particle size range (20–5000 μm) and higher detection rate (91%), while the detection range (&gt;50 μm) and rate (70%) of visual inspection through stereo microscopy were lower. For the identification of microplastic morphology, laser direct infrared imaging performed better, whereas micro-Fourier transform infrared spectroscopy had the advantage in determining the types of polymers present over micro-Raman spectrometry. The advantages, disadvantages, and detection rates of the above five detection methods were clarified during the detection process. Considering these findings and similar studies, we suggest three combinations of the evaluated methods to optimize the detection of PE-MPs.

Rapid Determination of Taraxacum kok-saghyz Rubber Content Using a Pyrolyzer Hyphenated with a Miniaturized Mass Spectrometer

Taraxacum kok-saghyz (TKS), a rubber-producing plant with excellent potential, emerges as a viable substitute for rubber tree (Hevea brasiliensis). While natural rubber is a desirable material, conventional techniques for assessing rubber content have faced challenges in meeting practical production requirements. To address this issue, we have developed a pyrolysis–mass spectrometry (PY-MS) instrument for the quantitative evaluation of natural rubber (NR) content in rubber-producing plants. The derived standard curve equation, established for the detection of TKS dry weight through external standard calibration, demonstrates a correlation coefficient (R2) surpassing 0.99. The method exhibits commendable recovery rates (93.27–107.83%), relative standard deviations (RSD ≤ 3.93%), and a swift analysis time of merely 10 min per sample, thereby enabling accurate and efficient quantification of NR dry weight. Additionally, the PY-MS system we designed can be modified for vehicular use, enabling on-site, in situ analysis, and it provides substantial support for TKS breeding and propagation efforts. This approach possesses significant potential for extensive utilization in the assessment of rubber content in rubber-producing plants other than TKS. The integration of pyrolysis–mass spectrometry for the identification of polymers with high molecular weight offers a valuable pathway for the examination of diverse polymers.