Urinary Metabolites of Isoliquiritigenin in Wistar Rats using UHPLC–TOF–MS-based Xenometabolomics

Isoliquiritigenin, a chalcone found in licorice root and many other plants, has shown potential antioxidant, estrogenic and antitumor activities. The present study was to investigate urinary metabolism of isoliquiritigenin in Wistar rats by ultra-high pressure liquid chromatography coupled to electrospray ionization TOF–MS (UHPLC–TOF–MS)-based xenometabolomics. Urine samples were collected before and after oral administration of isoliquiritigenin, and analyzed by UHPLC–TOF–MS. After deconvolution, the resulting data matrices were subjected to multivariate data analysis. Projection to latent structures discriminant analysis was performed to screen the metabolites. Fifteen urinary metabolites of isoliquiritigenin were screened out and 13 of them were further identified by Agilent MassHunter Software. The results of this work show that UHPLC–TOF–MS-based xenometabolomics was able to comprehensively identify the metabolites of phytochemicals and may represent a valuable tool for monitoring the food consumption.

     

Essential oil from Rhaponticum acaule L. roots: Comparative study using HS-SPME/GC/GC–MS and hydrodistillation techniques

The composition of essential oil extracted from Rhaponticum acaule L. roots growing wild in Algeria was studied by hydrodistillation (HD) and by Head-Space Solid Phase Micro-Extraction (HS-SPME). Quantitative but not qualitative differences have been found in the chemical composition of both analysed samples depending on the extraction method. However, the oil obtained from R. acaule roots shows that aliphatic alcohols were found to be the major class (69.2%), followed by the terpenes (5.5%), alkenes (5.2%) and alkynes (4.0%). In both cases the analysis were carried out using Gas Chromatography (GC) and Gas Chromatography–Mass Spectrometry (GC–MS). Our study shows that HS-SPME extraction could be considered as an alternative technique for the isolation of volatiles from plant. 25 components were identified in oil vs. 39 in the HS-SPME. However the oil composition of roots was mainly represented by a variety of aliphatic hydrocarbons (alcohols, aldehydes and ketones) and terpenes which are known for their antimicrobial activities.     

Monitoring of phthalates in foodstuffs using gas purge microsyringe extraction coupled with GC–MS

Phthalate esters (PAEs) are commonly used as nonreactive plasticisers in vinyl plastics to increase the flexibility of plastic polymers. Numerous studies have indicated that the PAEs as a class of endocrine-disrupting chemicals. In addition, the studies have also shown that a major source of human exposure to phthalates is the diet. To date, the largest problem in PAEs analysis is the high blank value because PAEs are widely used in various applications and products. To overcome this shortcoming, gas purge microsyringe extraction (GP-MSE) was applied, which established a new and low-blank-value analytical method for PAE analysis to analyse PAEs in foodstuffs. In this study, GP-MSE was used as a clean-up method, and the overall recoveries ranged from 85.7 to 102.6%, and the RSD was less than 10%. More importantly, this method can overcome the problem of the high blank value in PAE analysis. This method was applied for measuring PAEs in 78 foodstuffs. The results showed that a wide variety of PAE concentrations were found in the different groups, and the content of PAEs (varies from 658 to 1610 ng g⁻¹ fresh weight) is greatest in seafood. The concentrations were in the following order: DEHP > DBP > DEP ≈ DMP > BBP ≈ DNOP. Finally, the daily intake of PAEs was estimated for adults based on the levels of PAEs in foodstuffs. The total EDI_diet values of 3.2 and 12.9 μg kg⁻¹ bw d⁻¹ were calculated for DEHP based on the mean and highest concentrations in foodstuffs, respectively.     

Effect of epoxidized palm oil on the mechanical and morphological properties of a PLA–PCL blend

In this study, the effects of epoxidized palm oil (EPO) on the mechanical and morphological properties of a blend of two types of biodegradable polymer, poly(lactic acid) (PLA) and polycaprolactone (PCL), were investigated. The solution-casting process, with chloroform as a solvent, was used to prepare samples. Addition of EPO reduced the tensile strength and modulus but increased elongation at break for the PLA–PCL blend. The highest elongation at break was observed for the blend with 10 % (w/w) EPO content. Scanning electron microscopy (SEM) indicated that the fractured surface morphology of the PLA–PCL blend became more stretched and homogeneous in PLA–PCL–EPO. Possible interactions between the PLA–PCL blend and EPO were also characterized by use of Fourier-transform infrared (FTIR) spectroscopy. Thermal stability was studied by differential scanning calorimetry and thermogravimetric analysis. The results from FTIR and SEM revealed that the miscibility of the PLA–PCL blend was improved by addition of EPO.     

Structural identification of multidimensional metal–organic frameworks using soft x-ray tomography

This paper mainly discusses the applicability of using soft x-ray tomography technology to examine the multidimensional structure of metal–organic frameworks, such as their core-shell and hollow framework, by visually observing their corresponding images in different energy bands by different excitation energies for different elements. The results show that the use of soft x-ray tomography (SXT) can effectively observe the distribution of metals in the structure, as well as observe the type of hollow pores the metal – organic framework (MOF) possesses. This pioneering evaluation of MOFs via SXT shows excellent performance in the structure identification of multidimensional metal–organic frameworks.     

Exergetic and exergoeconomic analyses of a diesel engine fueled with binary and ternary blends of diesel–palm oil biodiesel–diethyl ether for various injection timings

Journal of Thermal Analysis and Calorimetry - In this study, ten different blends were prepared with binary and ternary combinations of diesel, palm oil biodiesel (0 vol%,...     

Determination of Pentachloronitrobenzene and Its Metabolites in Ginseng by Matrix Solid-Phase Dispersion and GC–MS–MS

A rapid method was developed for the determination of pentachloronitrobenzene (PCNB) and its metabolites pentachloroaniline, pentachlorothioanisole residues in ginseng. Extraction and clean-up were carried out in a single step and analysis was accomplished by gas chromatography–mass spectrometry with multiple reaction monitoring. The main parameters affecting extraction yield and selectivity, such as type and amount of dispersant material, clean-up co-sorbent and extraction solvent were evaluated. The best results were obtained using 1 g ginseng, 2 g florisil as dispersant sorbent, 0.5 g neutral alumina as clean-up co-sorbent, and subsequent extraction with 10 mL acetone–n-hexane (5:5, v/v) with assisted sonication and repeated with another 5 mL of the same solvent mixture. The method was validated by analysis of ginseng samples fortified at different concentration levels (0.01–0.10 mg kg^?1). Average recoveries (n = 5) ranged from 85 to 95% with relative standard deviation between 2.5 and 11.2%. Spiked blank samples were used as standards to counteract the matrix effect observed in the chromatographic determination. The detection limits ranged from 0.2 to 0.9 µg kg^?1 in ginseng. The method was applied to the analysis of PCNB and its metabolite residues in commercial ginseng samples.     

Simultaneous determination of five synthetic antioxidants in edible vegetable oil by GC–MS

A simple, quick and nontoxic analytical method for the simultaneous determination of five synthetic antioxidants [t-butyl-4-hydroxyanisole (BHA), 2,6-di-t-butyl-hydroxytoluene (BHT), t-butyl hydroquinone (TBHQ), ethoxyquin (EQ) and 2,6-di-tert-butyl-4-hydroxymethyl-phenol (Ionox 100)] in edible vegetable oil has been developed. The analytes were extracted by ethanol, then separated and detected by GC–MS. Extraction conditions such as volume of ethanol required, mixing time and number of extractions were investigated and optimized by an orthogonal array experimental design. The five compounds behaved linearly in the 0.100∼20.0 mg/L concentration range, and the limits of detection (LOD) for BHA, BHT, TBHQ, EQ and Ionox-100 were 1.00, 0.92, 11.5, 0.83 and 1.39 μg/L, respectively. The recoveries at the tested concentrations of 1.00, 20.0 and 100 mg/kg were 75.6∼123%, with coefficients of variation <10.0%. The proposed procedure was successfully applied to the simultaneous analysis of the five antioxidants in soybean oil, tea oil, edible blended oil, rap oil, peanut oil, peanut blended oil and sesame oil samples purchased from local supermarkets.     

Pyrolysis–GC/MS for the identification of macromolecular components in historical recipes

Analytical pyrolysis with thermally assisted hydrolysis and methylation was employed to investigate ancient ointments collected from Spanish vessels coming from the sixteenth century pharmacies. The ointments were reproduced on the basis of historical recipes and characterization was made in comparison with real samples. Characteristic markers indicate the presence of beeswax, of animal and plant lipids, and of natural resins. Analyses of old samples are consistent with the modern reproductions and with the analysis of raw materials. Multivariate data analysis was used to discriminate between the different types of lipidic materials, also in connection with their relative amount in the samples.     

Thermal degradation of α-pinene using a Py–GC/MS

Mediterranean forest fires may be accelerated, partly due to biogenic volatile organic compounds produced by vegetation, mainly monoterpenes largely represented by α-pinene. To model the propagation of biomass combustion, it is necessary to study the flammability of the produced gas mixture, and thus, necessary to identify the emitted volatile compounds. However, thermal degradation of monoterpenes is rarely experimented above 300 °C, whereas forest fires reach higher temperatures. Thus, in this work, we experimented a 2-min pyrolysis of α-pinene at temperatures from 300 to 800 °C using a Py–GC/MS device. Less than 1% of pyrolysis products were detected at 300 and 400 °C. The pyrolysis products increased then from 14 compounds at 500 °C to 31 compounds at 800 °C. Degradation of α-pinene started with its isomerization at 500 °C. At 800 °C, alkenes detected increased as well as aromatics produced through the Diels–Alder mechanism. These results are consistent with the literature on thermal degradation of α- and β-pinene presented in our article.

     

Characterization of Volatile Organic Metabolites in Lung Cancer Pleural Effusions by SPME–GC/MS Combined with an Untargeted Metabolomic Method

Headspace solid-phase microextraction and gas chromatography/mass spectrometry (HS-SPME–GC/MS) method combined with XCMS Online was tentatively applied to characterize the dysregulated volatile organic metabolites (VOMs) in benign and malignant pleural effusions. A total of 9 dysregulated feature groups were isolated from metabolic features in 35 pleural effusion samples (20 benign effusions and 15 malignant ones from lung cancer patients). Principle component analysis, partial least squares discriminant analysis (PLS-DA) and orthogonal PLS-DA were built to separate benign from malignant pleural effusion groups and to find dysregulated metabolites in significantly different amounts between the two groups. Four dysregulated VOMs such as 2-ethyl-1-hexanol, cyclohexanone, 1,2,4,5-tetramethylbenzene and naphthalene were selected according to the variable influence on the projection value. The concentration of the four dysregulated VOMs in benign and malignant effusions were further determined by external standard method. The median concentrations of 4 VOMs in malignant effusion samples were from 4.7 to 91,121.9 nM, whereas their median levels were only 1.9–318.3 nM in benign ones. The results show that the proposed SPME–GC/MS-based metabolomic approach combined with XCMS Online data processing is a simple, rapid and available method for the characterization of dysregulated VOMs in malignant and benign pleural effusions.     

Reconstruction and analysis of correlation networks based on GC–MS metabolomics data for young hypertensive men

The awareness, treatment, and control rates of hypertension for young adults are much lower than average. It is urgently needed to explore the variances of metabolic profiles for early diagnosis and treatment of hypertension. In current study, we applied a GC–MS based metabolomics platform coupled with a network approach to analyze plasma samples from young hypertensive men and age-matched healthy controls. Our findings confirmed distinct metabolic footprints of young hypertensive men. The significantly altered metabolites between two groups were enriched for the biological module of amino acids biosynthesis. The correlations of GC–MS metabolomics data were then visualized as networks based on Pearson correlation coefficient (threshold = 0.6). The plasma metabolites identified by GC–MS and the significantly altered metabolites (P < 0.05) between patients and controls were respectively included as nodes of a network. Statistical and topological characteristics of the networks were studied in detail. A few amino acids, glycine, lysine, and cystine, were screened as hub metabolites with higher values of degree (k), and also obtained highest scores of three centrality indices. The short average path lengths and high clustering coefficients of the networks revealed a small-world property, indicating that variances of these amino acids have a major impact on the metabolic change in young hypertensive men. These results suggested that disorders of amino acid metabolism might play an important role in predisposing young men to developing hypertension. The combination of metabolomics and network methods would provide another perspective on expounding the molecular mechanism underlying complex diseases.     

Non-isothermal thermogravimetric analysis of pyrolysis kinetics of four oil shales using Sestak–Berggren method

Journal of Thermal Analysis and Calorimetry - In this study, the non-isothermal pyrolysis method was used to investigate the pyrolysis characteristics of oil shale from four areas: namely Nongan,...     

Separation and identification of trinucleotide–melphalan adducts from enzymatically digested DNA using HPLC–ESI–MS

Melphalan is a bifunctional alkylating agent that covalently binds to the nucleophilic sites present in DNA. In this study we investigated oligonucleotides prepared enzymatically from DNA modified with melphalan. Calf thymus DNA was incubated in-vitro with melphalan and the resulting modifications were enzymatically cleaved by means of benzonase and nuclease S1. Efficient sample preconcentration was achieved by solid-phase extraction, in which phenyl phase cartridges resulted in better recovery of the modified species than C₁₈. The applied enzymatic digestion time resulted in production of trinucleotide adducts which were efficiently separated and detected by use of reversed-phase HPLC coupled to an ion-trap mass spectrometer with electrospray ionization. It was assumed that melphalan could act as both a monofunctional and bifunctional alkylating agent. Mono-alkylated adducts were much more abundant, however, and the alkylation site was located on the nucleobases. On the other hand, we unequivocally identified cross-link formation in DNA, even though at low abundance and only a few adduct types were detected. Figure Different Alkylation reactions of Melphalan with DNA     

GC–MS characterisation and antibacterial activity evaluation of Nigella sativa oil against diverse strains of Salmonella

Salmonella resistance is becoming a worldwide serious health issue in these days; therefore, it is an urgent need to develop some alternative approaches to overcome this problem. Twenty bacterial strains were isolated and purified from different environmental sources and confirmed as Salmonella by morphological and biochemical analyses. Further confirmation was done by 16s rRNA sequencing. Antibiotic susceptibility test was performed by well diffusion assay against different concentrations of Ceftriaxone and Ciprofloxacin. The behaviour of both antibiotics was different against diverse strains of Salmonella. Salmonella strains resistant to both antibiotics were analysed for antibacterial activity of natural extracts of Nigella sativa (black seeds). N. sativa oil was found to be more effective against Salmonella species for which even Ceftriaxone and Ciprofloxacin were ineffective. Gas chromatography and mass spectrometry analysis of N. sativa oil was also accomplished, exhibiting 10 compounds including thymoquinone, p-cymene, cis-carveol, thymol, α-phellandrene, α-pinene, β-pinene, trans-anethole, α-longipinene and longifolene.     

Classification of methamphetamine seized in different regions of Iran using GC–MS and chemometrics

According to the intensive physical and mental risk of methamphetamine (crystal) on human, it is important to focus on the prevention of distribution and decrease of the usage of methamphetamine. In the current study, attempts was on the application of GC–MS analysis combined with chemometrics to present a classification model for methamphetamine samples seized in different regions of Iran. In this work, principal component analysis was not able to discriminate samples from different geographic regions. For the discrimination goal, partial least squares discriminant analysis (PLS-DA) and extended canonical variate analysis (ECVA) were utilized and a classification model was constructed to differentiate methamphetamine samples seized in three regions of Iran, i.e., south, west and central. PLS-DA showed good performance in calibration step; however, ECVA indicated better prediction ability. The difference of the classified samples can be because of difference in the synthetic root used in each of three investigated regions. Class sensitivity and selectivity for all three regions were excellent in ECVA model with nonsignificant misclassifications. Cross-validation and external validation using a test set confirmed the obtained classification model. Statistical results indicated a regional production/distribution pattern in the country.     

Preparation of superhydrophobic materials for oil/water separation and oil absorption using PMHS–TEOS-derived xerogel and polystyrene

Fabrication of suerhydrophobic materials towards oil/water separation and oil absorption has been receiving great attention nowadays, due to the significant increase of industrial oily wastewater and frequent accident of oil spill. In most previous studies, the usage of expensive precursors restricted the wide applications of prepared superhydrophobic materials. In this work, superhydrophobic filter paper, fabric and polyester sponges were fabricated by dip-coating the mixed solution of polystyrene and xerogels, which were prepared with tetraethoxysilane and polymethylhydrosiloxane, based on previous work. The as-fabricated fabric can effectively separate oil and water mixtures and possesses excellent reusability; more significantly, the materials maintained its good hydrophobic and excellent oil/water separation capacity even after ten cycles. Interestingly enough, the stability was provided, as a result, the fabric still exhibited superhydrophobic after 100 abrasion times and showed high repellency towards many liquids with different pH values. Additionally, the coated polyester sponges can quickly absorb various oil and organic liquid, which will offer a practical application for the treatment of seawater or oily wastewater. By contrast, this experiment process is simple and avoided using costly fluoro-chemicals or complicated fabrication process.     

Analysis of phenanthrene biodegradation by using FTIR,UV and GC–MS

The aim of this paper is to assess the biodegradation of phenanthrene by Flavobacteria FCN2 which was isolated from coke plant sludge via a classical shaken liquid medium enrichment method. The strain FCN2 can decompose phenanthrene (50 mg l^?1) completely within 5 days. The values of pH decrease to 6.7 from 7.2 during degradation periods. And a detailed phenanthrene metabolism was assayed by using FTIR, UV and GC–MS. For FTIR, appearance of new broad absorption bands at 2858 cm^?1, 2927 cm^?1, 2955 cm^?1 and another new strong absorption band at 1734 cm^?1 in metabolites demonstrates that carboxyl group produced during phenanthrene degradation. Besides this, a very strong absorption band appears at 1260 cm^?1. It is ascribed to C–C stretching vibration band in carbonyl group of arone. Two weak adsorption at 334 nm and 349 nm in UV spectra were assigned to the n-π* transition of CO of aldehyde. Two metabolites, phenanthrene-dihydrodiol and naphthalene-1-diol were identified in neutral fraction of phenanthrene degradation by using GC–MS. As a result carboxylic acids and arone were generated during biodegradation of phenanthrene by Flavobacteria FCN2.     

Assessment of the oxidative stability of lubricant oil using fiber-coupled fluorescence excitation–emission matrix spectroscopy

The fluorescence of antioxidant additives in lubricant oil was used as an indicator of oxidative stability of the oil. It was found that the decrease in fluorescence intensities of phenyl-α-napthylamine, its dimer, and another unidentified antioxidant coincide with the formation of decomposition products of the oil base stock. Simple kinetic models were developed that were capable of describing antioxidant reactions as a pseudo first-order processes. It is shown that fluorescence excitation emission matrix (EEM) spectroscopy coupled with an optical fiber probe can provide real-time assessment of the oxidative stability of the lubricant. Parallel factor (PARAFAC) analysis was used to correlate the component scores to the oil breakdown number.     

A multi-analytical approach for the identification of aloe as a colorant in oil–resin varnishes

Aloe plants have been widely documented in artists’ treatises dating from the sixteenth to the nineteenth century as a source of colorant to achieve lustrous golden glazes on tin- and silver-foiled objects and warm-toned finishes on musical instruments, such as violins. Aloe extracts contain characteristic anthraquinone and phenolic components which impart a distinctive orange tone and fluorescence to mixtures containing them. Because of the low concentration of colorant in the coatings and its probable degradation by high temperature during manufacture, the identification of aloe in heated oil–resin mixtures represents an analytical challenge. For this reason, the possible presence of aloe in glazes and coatings has been largely overlooked. This paper describes various analytical approaches to the identification of aloe in historic samples, from comparison with results obtained from reference standards and mock-up samples. Complementary analytical techniques including thermally assisted hydrolysis and methylation–gas chromatography–mass spectrometry, high-performance liquid chromatography, laser desorption–mass spectrometry, matrix-assisted laser desorption-ionization-mass spectrometry and surface-enhanced Raman scattering were used. Different chemical markers were identified by the individual methods and the advantages and limitations of each technique for the identification of aloe in oil–resin varnishes are discussed.