Analysis Of Chemical Components Research Articles

A 3-year application of different mycorrhiza-based plant biostimulants distinctively modulates photosynthetic performance, leaf metabolism, and fruit quality in grapes (Vitis vinifera L.).

The use of microbial biostimulants in agriculture is recognized as a sustainable approach to promoting crop productivity and quality due to improved nutrient uptake, enhanced stress tolerance, and improved ability to cope with non-optimal environments. The present paper aimed to comparatively investigate the effect of seven different commercial mycorrhizal-based treatments in terms of yield, phytochemical components, and technological traits of Malvasia di Candia Aromatica grape (Vitis vinifera L.) plants. Metabolomic analysis and photosynthetic performance were first investigated in leaves to point out biochemical differences related to plant growth. Higher photosynthetic efficiency and better PSII functioning were found in biostimulant-treated vines, reflecting an overall decrease in photoinhibition compared to untreated plants. Untargeted metabolomics followed by multivariate statistics highlighted a robust reprogramming of primary (lipids) and secondary (alkaloids and terpenoids) metabolites in treated plants. The analysis of berry yield and chemical components exhibited significant differences depending on the biostimulant product. Generally, berries obtained from treated plants displayed improved contents of polyphenols and sugars, while yield remained unchanged. These results elucidated the significant role of microbial biostimulants in determining the quality of grape berries and eliciting biochemical changes in vines.

Component Analysis and Identification of Ancient Glass Products Based on Statistical Methods

This paper analyzes its role in the composition analysis and identification of ancient glass products by flexible use of statistical methods, and emphasizes four statistical methods: systematic clustering algorithm, K-means algorithm, logistic regression model and grey correlation analysis. Taking the C project of CUMCM in 2022 as an example, this paper systematically introduces these four common data classification and statistical methods to classify and analyze the given data. In this paper, suitable chemical components of high potassium and lead barium glass were selected for subdivision, and the specific division methods and results w ere given. The chemical composition of glass relics of unknown category was analyzed to identify their type. The grey correlation matrix of surface weathering of high-potassium cultural relics was obtained, and the correlation degree of chemical components was analyzed. This greatly promotes the composition analysis and identification of chemical components in ancient relics.

Determination of the content of major chemical components and bioactive compounds and antioxidant ability of Hong Quan (Flacourtia jangomas (Lour.) Raeusch) fruit cultivated in An Giang, Vietnam

Hong Quan (Flacourtia jangomas (Lour.) Raeusch) is a new fruit that has appeared recently and it is cultivated with other orchards or under forest canopy of Tri Ton and Tinh Bien district at An Giang province. Since this fruit has not been popularized in Vietnam, there is a shortage in research about chemical compositions of Hong Quan. Therefore, quantitative analysis of main chemical components, bioactive compounds and antioxidant activity of this kind of fruit need to be carried out to enhance its applications in food. Results showed that Hong Quan fruits contain 76.50% ± 2.56 of moisture, carbohydrate is 24.86% ± 1.54, protein is 9.19% ± 0.49, lipid is 0.68% ± 0.21, total sugar is 10,91% ± 0.88, ash is 1.05% ± 0.08, fiber is 8.39% ± 0.95 and vitamin C is 81.62 ± 3.99 mg/100g. The content of bioactive compounds such as carotenoids, phenolics, tannins, alkaloids, saponins and flavonoids were 9.87 ± 0.40 mg/100g, 456.32 ± 23.81 mgGAE/100g, 944.08 ± 26.31 mgTAE/100g, 586.68 ± 44.56 mgCE/100g, 20.87 ± 2.00 mgSE/100g and 65.95 ± 2.92 mgQE/100g fresh weight respectively. Moreover, antioxidant capacity of extract ethanol from fruit was high level as the free radical scavenging ability (DPPH) at 88.65% ± 1.23, the ability to reduce iron (FRAP) at 15.24 ± 0.26 mM FeSO4/100g and the antioxidant ability index (AAI) at 8.13 ± 0.82. Hong Quan fruit promisingly could be a good source of commercial processing products or cosmetic due to high level of nutrients and functional compounds.

Cytotoxic Potential of Essential Oil Isolated from Clibadium Surinamese L Leaves Against T47D Breast and HeLa Cervical Cancer Cells

Semambu (C. surinamense L) plant is a shrub plant that is easy to find. Several terpenoid compounds have been isolated from this plant, previous studies have shown cytotoxic activity of terpenoid class compounds. Terpenoid compounds in a plant are mostly found in essential oils (monoterpenes and sesquiterpenes). So far, there has been no report on the cytotoxic potential of essential oils from the leaves of this plant. It is necessary to isolate the essential oils from C. surinamense L leaves and test their cytotoxic potential. Isolation of essential oil of C. surinamense L leaves was carried out by hydrodistillation method, the oil was obtained in the form of a light yellow liquid with a specific gravity of 0.968 g/mL. Analysis of chemical components with Gas Chromatography-Mass-Spectrometry (GC-MS) through comparison of data from the National Institute of Standards and Technologies (NIST) found that there were 55 compounds (monoterpene and sesquiterpene groups) with six main compounds, namely β-caryophyllene (30.4%), β-sesquiphellandrene (8.46%), 3 carene (8.16%), α-bisabolene (4.05%), α-humulene (4.0%), and epi- bicyclosesquiphellandrene (4.0%). The potential cytotoxic test of essential oil from isolation showed highly cytotoxic activity with the Brine Shrimp Lethality Test (BSLT) method against Artemia salina L shrimp larvae with LC50 value of 0.9261 μg/mL and Microculture tetrazolium test (MTT) method against T47D breast cancer cells and HeLa cervix with IC50 values of 12.72 μg/mL and 30.14 μg/mL.

Chemical subclasses of ancient glass based on K-means

After the opening of the Maritime Silk Road, glass products flooded into China, which is an epitome of ancient China's foreign exchanges. Due to its exposure to the environment, the action of air, water, acid, and alkali substances, the chemical composition of the glass surface changes, thus affecting the judgment of the category. In this study, the subclassification of ancient cultural relics realized the chemical composition analysis of ancient glass and its subclass classification. First of all, the classification rules of high potassium glass and lead barium glass are obtained through analysis, which is divided into four categories: high potassium weathering, high potassium without weathering, lead barium weathering, and lead barium without weathering. Second, the cluster copula map was established, and the subclassification results were obtained combined with the K-means algorithm. Finally, the content of the chemical composition is different, so the division method is reasonable. After changing the original data, that is, changing the content of a chemical composition (-10%, -5%, 5%, 5%, 10%) into the original model, the experimental results can conclude that the model has high sensitivity. Finally, the construction of the subclassification model in this study can better provide the technical support for the analysis and identification of ancient chemical components, which is of great significance and value in the fields of archaeology, cultural heritage protection and, materials science.

Elemental composition x-ray fluorescence analysis with a TES-based high-resolution x-ray spectrometer

The accurate analysis of the elemental composition plays a crucial role in the research of functional materials. The emitting characteristic x-ray fluorescence (XRF) photons can be used for precisely discriminating the specified element. The detection accuracy of conventional XRF methodology using semiconductor detector is limited by the energy resolution, thus posing a challenge in accurately scaling the actual energy of each XRF photon. We adopt a novel high-resolution x-ray spectrometer based on the superconducting transition-edge sensor (TES) for the XRF spectroscopy measurement of different elements. Properties including high energy resolution, high detection efficiency and precise linearity of the new spectrometer will bring significant benefits in analyzing elemental composition via XRF. In this paper, we study the L-edge emission line profiles of three adjacent rare earth elements with the evenly mixed sample of their oxide components: terbium, dysprosium and holmium. Two orders of magnitude better energy resolution are obtained compared to a commercial silicon drift detector. With this TES-based spectrometer, the spectral lines overlapped or interfered by background can be clearly distinguished, thus making the chemical component analysis more accurate and quantitative. A database of coefficient values for the line strength of the spectrum can then be constructed thereafter. Equipped with the novel XRF spectrometer and an established coefficient database, a direct analysis of the composition proportion of a certain element in an unknown sample can be achieved with high accuracy.

Enhancing enzymatic hydrolysis of waste sunflower straw by clean hydrothermal pretreatment

Hydrothermal pretreatment is an effective way to change the lignocellulose structure and improve its saccharification. An efficient hydrothermal pretreatment of sunflower straw was conducted when the severity factor (LogR0) was 4.1. 58.8% of xylan and 33.5% of lignin were removed at 180 °C for 120 min with a solid-to-liquid ratio of 1:15. A series of characterizations (such as X-ray diffraction, Fourier Transform infrared spectroscopy, scanning electron microscopy, chemical component analysis, cellulase accessibility) proved that hydrothermal pretreatment destroyed sunflower straw surface structure, enlarged its pores, and enhanced the accessibility to cellulase (371.2 mg/g). After the enzymatic saccharification of treated sunflower straw for 72 h, 68.0% yield of reducing sugar and 61.8% yield of glucose were achieved, and 3.2 g/L xylo-oligosaccharide was obtained in the filtrate. Overall, this easy-to-operate and green hydrothermal pretreatment could effectively destroy the surface barrier of lignocellulose, help remove lignin and xylan, and increase the enzymatic hydrolysis efficiency.

Nanometer Resolution Mass Spectro-Microtomography for In-Depth Anatomical Profiling of Single Cells.

Visually identifying the molecular changes in single cells is of great importance for unraveling fundamental cellular functions as well as disease mechanisms. Herein, we demonstrated a mass spectro-microtomography with an optimal voxel resolution of ∼300 × 300 × 25 nm3, which enables three-dimensional tomography of chemical substances in single cells. This mass imaging method allows for the distinguishment of abundant endogenous and exogenous molecules in subcellular structures. Combined with statistical analysis, we demonstrated this method for spatial metabolomics analysis of drug distribution and subsequent molecular damages caused by intracellular drug action. More interestingly, thanks to the nanoprecision ablation depth (∼12 nm), we realized metabolomics profiling of cell membrane without the interference of cytoplasm and improved the distinction of cancer cells from normal cells. Our current method holds great potential to be a powerful tool for spatially resolved single-cell metabolomics analysis of chemical components during complex biological processes.

New dating approach based on the petrographical, mineralogical and chemical characterization of ancient lime mortar: case study of the archaeological site of Hippo, Annaba city, Algeria

This work presents the results of a multidisciplinary study on the characterization of the composition of certain joint mortars from the ancient city of Hippo (Algeria), one of the most important North African cities in antiquity. Twenty mortar samples were analysed by X-Ray Fluorescence (XRF), powder X-ray diffraction (XRPD), optical microscopy (OM), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDS) and thermogravimetric analysis (TGA). Their main physical properties, like solid and dry density and porosity, have been measured by geotechnical procedures. The typological observation by OM showed the existence of four types of sand used as aggregates that ranged from fine to coarse and were mixed with a white to russet natural lime binder. These mortars consisted mainly of mixtures of calcite and rock fragments, and sometimes pieces of red tile. It was recognized that the origins of the natural granules were sands produced by marine erosion of the Edough Mountains. The analysis by XRPD and TGA indicates that the mortars consisted of a mixture of lime/aggregates of low to medium hydraulicity. The analysis of the main chemical components by XRF allowed for the confirmation of the dating of certain monuments and suggested a new dating for other monuments.

Centaurea triumfetii essential oil chemical composition, comparative analysis, and antimicrobial activity of selected compounds

The essential oils from the Centaurea genus are well known for their pharmacological properties. The most abundant and dominant chemical components in Centaurea essential oils are ß-caryophyllene, hexadecanoic acid, spathulenol, pentacosane, caryophyllene oxide, and phytol. However, whether these dominant components are the key drivers for observed antimicrobial activity remains unclear. Thus, the aim of this study was dual. Here we provide comprehensive, literature-based data to correlate the chemical compounds in Centaurea essential oils with the tested antimicrobial activity. Secondly, we characterized the essential oil of Centaurea triumfettii All. squarrose knapweed using coupled system gas chromatography–mass spectrometry and tested its phytochemicals for antimicrobial activity against E. coli and S. epidermis using disc diffusion assay and monitoring their growth in Muller Hinton broth. The most abundant compounds in C. triumfettii essential oil were hexadecanoic acid (11.1%), spathulenol (10.8%), longifolene (8.8%), germacrene D (8.4%), aromadendrene oxide (6.0%) and linoleic acid (5.3%). Based on our analysis of literature data from other Centaurea essential oils, they were positively correlated with antimicrobial activity. Using an agar disk diffusion method, tested chemical constituents did not show experimental evidence to support this positive correlation to antimicrobial activity when we tested them as pure components. The antibacterial effect of essential oil constituents may be related to a complex synergistic, rather than a single component as suggested by performed network pharmacology analysis, underlying the theoretical interactions between the essential oil phytochemicals listed as potentially responsible for antimicrobial activity and should be confirmed in further in-depth studies. This is the first report on the comparative analysis of Centaurea essential oils with good antimicrobial activity, as well as the first analysis of chemical components of the essential oil from C. triumfettii and the first report of antimicrobial activity of the representative, pure components: aromadendrene, germacrene D, spathulenol, longifolene, and the mixture of selected chemical compounds. This work contributes to the body of knowledge on the genus Centaurea and C. triumfettii species.

Quantitative determination of petroleum hydrocarbons in oily sludge following efficient n-heptane separation

Accurate analysis of the main chemical components of oil-bearing sludge is an important prerequisite for effective soil remediation and resource reuse. However, precise analysis of the extract components is difficult to achieve because of the mutual interference of saturates, aromatics, and resins, collectively called SAR, and asphaltene that are introduced during chloroform extraction. In this study, SAR was efficiently extracted using n-heptane, while asphaltene components were retained in soil because of their insolubility in n-heptane. The maximum yield of SAR extraction was 27.0%, indicating an increase of 1.75% compared to chloroform extraction. The extracted SAR components were separated by chromatography and the main structural units and components were analyzed. The results show that saturates, aromatics, and resins have a single component, a high content of major components, and contain fewer impurities using n-heptane extraction. Moreover, the solubility of asphaltene was inhibited during the effective extraction of SAR components with n-heptane and did not influence the subsequent analysis of SAR component. Efficient SAR extraction, accurate SAR component analysis, and high efficiency asphaltene separation was achieved using n-heptane-extraction-assisted pyrolysis. This provides a new method for the component analysis of oily sludge and promotes its efficient separation.

Laser-induced breakdown spectroscopy instrument and spectral analysis for deep-ocean Fe-Mn crusts

IntroductionMarine ferromanganese crusts are potentially important metal resources.The deep-ocean research and survey ships often need to carry out rapid chemical element component analysis of mineral resources, so as to plan for the geological resource exploration mission.MethodsThe laser-induced breakdown spectroscopy can obtain the spectrum of chemical elements by the plasma excited by high-energy laser irradiation on the surface of the sample. A laser induced breakdown spectroscopy optical system for the detection of deepocean ferromanganese crusts is designed and built, which can meet the requirements of near-insitu chemical component detection of deep-ocean mineral resources on ocean-going survey ships.ResultsHyperspectral data of Fe-Mn crusts are carried out by the Laser-induced breakdown spectroscopy (LIBS) system during a deep-sea exploration mission at a depth of 2,490 m in the South China Sea. The experimental parameters of laser energy and spectral acquisition delay are optimized to improve the spectral measurement accuracy. Based on the calibration-free method, the significant spectral features of the chemical elements Fe and Mn were obtained through proper alignment with the National Institute of Standards and Technology (NIST) chemical element spectral library.DiscussionThe LIBS instrument can be placed on board long-range survey vessels in the future to provide a fast, convenient, accurate, and economical detection method for deep-ocean resource exploration.

Effects of donkey milk on UVB-induced skin barrier damage and melanin pigmentation: A network pharmacology and experimental validation study.

Dairy products have long been regarded as a controversial nutrient for the skin. However, a clear demonstration of donkey milk (DM) on skincare is required. In this study, spectrum and chemical component analyses were applied to DM. Then, the effects of DM on UVB-induced skin barrier damage and melanin pigmentation were first evaluated in vitro and in vivo. Cell survival, animal models, and expression of filaggrin (FLG) were determined to confirm the effect of DM on UVB-induced skin barrier damage. Melanogenesis and tyrosinase (TYR) activity were assessed after UVB irradiation to clarify the effect of DM on whitening activities. Further, a network pharmacology method was applied to study the interaction between DM ingredients and UVB-induced skin injury. Meanwhile, an analysis of the melanogenesis molecular target network was developed and validated to predict the melanogenesis regulators in DM. DM was rich in cholesterols, fatty acids, vitamins and amino acids. The results of evaluation of whitening activities in vitro and in vivo indicated that DM had a potent inhibitory effect on melanin synthesis. The results of effects of DM on UVB‑induced skin barrier damage indicated that DM inhibited UVB-induced injury and restored skin barrier function via up-regulation expression of FLG (filaggrin). The pharmacological network of DM showed that DM regulated steroid biosynthesis and fatty acid metabolism in keratinocytes and 64 melanin targets which the main contributing role of DM might target melanogenesis, cell adhesion molecules (CAMs), and Tumor necrosis factor (TNF) pathway. These results highlight the potential use of DM as a promising agent for whitening and anti-photoaging applications.

Qualitative and Quantitative Analyses of the Chemical Components of Peels from Different Pomelo Cultivars (Citrus grandis [L.] Osbeck) Based on Gas Chromatography-Mass Spectrometry, Ultraperformance Liquid Chromatography-Q-Exactive Orbitrap-MS, and High-Performance Liquid Chromatography-Photodiode Array Detection.

The volatile and nonvolatile phytochemicals in peels of 5 major pomelo cultivars (including Citrus grandis cv. Yuhuanyou, C. grandis cv. Liangpingyou, C. grandis cv. Guanximiyou, C. grandis cv. Duweiwendanyou, and C. grandis cv. Shatianyou) from 11 places in China were characterized. First, 194 volatile compounds in pomelo peels were identified by gas chromatography-mass spectrometry (GC-MS). Of these, 20 major volatile compounds were subjected to cluster analysis. The heatmap indicated that the volatile compounds in peels of C. grandis cv. Shatianyou and C. grandis cv. Liangpingyou were different from those in other varieties, while there was no difference among C. grandis cv. Guanximiyou, C. grandis cv. Yuhuanyou, and C. grandis cv. Duweiwendanyou from different origins. Second, 53 nonvolatile compounds were identified in pomelo peels by ultraperformance liquid chromatography-Q-exactive orbitrap tandem MS (UPLC-Q-exactive orbitrap-MS), of which 11 components were detected for the first time. Third, six major nonvolatile compounds were quantitatively analyzed with high-performance LC-photodiode array detection (HPLC-PDA). Combining the results of HPLC-PDA and the heatmap, 6 nonvolatile compounds in 12 batches of pomelo peel were well separated among varieties. Comprehensive analysis and identification of chemical components in pomelo peels are of great significance for their further development and utilization.

Monoterpenoids from Paeoniae Radix Rubra based on UPLC-Q-TOF-MS

The ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry(UPLC-Q-TOF-MS) was used to conduct the qualitative analysis of the monoterpene chemical components from Paeoniae Radix Rubra. Gradient elution was performed on C_(18) HD(2.1 mm×100 mm, 2.5 μm) column with a mobile phase of 0.1% formic acid(A) and acetonitrile(B). The flow rate was 0.4 mL·min~(-1) and the column temperature was 30 ℃. MS analysis was conducted in both positive and negative ionization modes using electrospray ionization(ESI) source. Qualitative Analysis 10.0 was used for data processing. The identification of chemical components was realized by the combination of standard compounds, fragmentation patterns, and mass spectra data reported in the literature. Forty-one monoterpenoids in Paeoniae Radix Rubra extract were identified. Among them, 8 compounds were reported in Paeoniae Radix Rubra for the first time and 1 was presumed to be the new compound 5″-O-methyl-galloylpaeoniflorin or its positional isomer. The method in this study realizes the rapid identification of monoterpenoids from Paeoniae Radix Rubra and provides a material and scientific basis for quality control and further study on the pharmaceutical effect of Paeoniae Radix Rubra.

Phytochemical analysis of Annona atemoya seed extract by HPLC and their ability to inhibit the growth of Agrobacterium tumefaciens

Abstract. Al-Barhawee NIK, Qasim WS, Abdlla YA. 2023. Phytochemical analysis of Annona atemoya seed extract by HPLC and their ability to inhibit the growth of Agrobacterium tumefaciens. Biodiversitas 24: 603-608. The main objective of this study was to determine the effectiveness of Annona atemoya seeds crude alcoholic extract utilizing nine different concentrations (0.0020, 0.0039, 0.0060, 0.0080, and 0.00100 mg/ml). Agrobacterium tumefaciens causes crown gall disease in numerous plant crops causing significant economic losses. Medicinal plants contain chemical compounds (a group of secondary metabolites) known to have antibacterial properties. The result showed that the minimum inhibitory concentration was (0.0313 mg/ml) using agar diffusion technique, while it ranged from (0.0156-0.0313 mg/ml) in the minimal microplate inhibitory concentration test. The crude alcoholic extract of A. atemoya seeds contains alkaloids, flavonoids, glycosides, tannins, phenols, and proteins, but not saponins, based on the results of qualitative analysis of chemical components. HPLC analysis revealed that the extract contained quercitin, rutin, valine, and camphor which were found in the amount of 33.09, 139.39, 0.061, and 7.43 ppm/ml, respectively. Therefore the present finding suggests that A. atemoya seed extract may be used as a biological control to inhibit crown gall formation in plants. This is the first study of the antimicrobial activity of A. atemoya seed alcoholic extract on the growth of plant pathogenic bacteria.

Qualitative Analysis of Chemical Components of Jasminum Sambac and Rosa Damascena by Gas Chromatography-Mass Spectrometry and Its Influences on E-nose to Classify Odour

Qualitative Analysis of Chemical Components of Jasminum Sambac and Rosa Damascena by Gas Chromatography-Mass Spectrometry and Its Influences on E-nose to Classify Odour

X-ray structural analysis of the BaO and TiO2 starting compounds and initial mechanochemical activation

The aim of this research was to obtain an initial characterization of the BaO and TiO2 components, as well as to conduct preliminary research into the possibility of activating the initial components in order to obtain barium titanate. Chemical and X-ray structural analysis of the initial components was performed. In order to determine the possibility of applying a mechanochemical activator and the activation time in which the first intermediate compounds were formed by the activation of the starting substances, the system was activated for 30 minutes. After this, an X-ray structural analysis was performed and certain changes in the crystal lattice of the starting components were made. X-ray structural analysis showed that during grinding, amorphization of the initial components occurred, which is the first stage in the process of obtaining titanate, as well as the presence of a small amount of barium titanate, which is indicating the presence of an intermediate compound in the process of finally obtaining barium titanate.

Optimization of the Solid-State Culture Conditions and Chemical Component Analysis of Poria cocos (Agaricomycetes).

The optimal cultivation conditions and chemical components of Poria cocos fruiting bodies were examined by employing the single factor and response surface methods to screen for optimal conditions for artificial cultivation. The differences in chemical composition among the fruiting bodies, fermented mycelium, and sclerotia of P. cocos were compared using UV spectrophotometry and high-performance liquid chromatography (HPLC). The optimal growth conditions for P. cocos fruiting bodies were 28.5°C temperature, 60% light intensity, and 2.5 g pine sawdust, which resulted in the production of numerous basidiocarps and basidiospores under microscopic examination. Polysaccharides, triterpenoids, and other main active components of P. cocos were found in the fruiting bodies, sclerotia, and fermented mycelium. The triterpenoid components of the fruiting bodies were consistent with those of the sclerotia. The content of pachymic acid in the fruiting bodies was significantly higher than that in the sclerotia, with a value of 33.37 ± 0.1902 mg/g. These findings provide novel insights into the sexual breeding and comprehensive development and utilization of P. cocos.

Elucidation of exhaust gas recirculation deposit formation mechanism based on chemical analysis of components

To comply with strict emission regulations, vehicles are equipped with exhaust gas recirculation (EGR) systems that control nitrogen oxide emissions by returning part of the exhaust gas to the intake air. However, since deposits form in the EGR piping and valves, leading to pipe clogging, valve sticking, and in the worst case, failure of these components, there is a need to clarify the mechanism of deposit formation to predict and reduce deposit accumulation. While most of the previous studies have focused on the powdery deposits that clog the EGR cooler, this study aims to elucidate the formation mechanism of both the lacquer-like hard deposits and wet soft deposits that cause EGR valve sticking by quantitative and molecular-level analyses. In these experiments, a portion of the exhaust gas from an actual diesel engine without soot removed by diesel particulate filter (DPF) was used. Deposits were continuously generated on a simulated EGR line with a downstream temperature gradient from the engine outlet, while measuring the inner wall temperature. The collected deposits were subjected to comprehensive chemical analysis. The analysis showed that 75 % of the solvent-soluble deposit components were polycyclic aromatic hydrocarbons (PAHs), which were the main component of the hard and soft deposits. Most of the PAHs in the hard deposits that formed at a high inner wall temperature were C17 or higher. The hard deposit with an inner wall temperature of 137 °C contained 0.016 mg/cm2 of 6-ring benzo[ghi]perylene and 0.26 × 10-3 mg/cm2 of 4-ring pyrene. On the other hand, the soft deposit is formed at an inner wall temperature of 80 °C, contained 0.022 mg/cm2 of pyrene, which is significantly more than in the hard deposit. This shows that PAHs in the exhaust gas condense when the gas temperature reaches their dew points, and that the deposits formed at higher inner wall temperatures contain more PAHs with higher boiling points. High-molecular weight aromatic compounds with oxygen and nitrogen functional groups were detected in the solvent-insoluble deposit components. These compounds were found to be derived from the polymerization of oxygenated and nitrogenated PAHs through dehydration condensation and cross-linking reactions.