Effect of different temperatures on the properties of pyrolysis products of Parthenium hysterophorus

This research encompasses the use of noxious weed Parthenium hysterophorus as feedstock for pyrolysis carried out at varying temperatures of 300, 450 and 600°C. Temperature significantly affected the yield and properties of the pyrolysis products including char, syngas and bio-oil. Biochar yield decreased from 61% to 37% from 300 °C to 600 °C, whereas yield of gas and oil increased with increasing temperature. The pyrolysis products were physico-chemically characterized. In biochar, pH, conductivity, fixed carbon, ash content, bulk density and specific surface area of the biochar increased whereas cation exchange capacity, calorific value, volatile matter, hydrogen, nitrogen and oxygen content decreased with increasing temperature. Thermogravimetric analysis showed that the biochar prepared at higher temperature was more stable. Gas Chromatography-Mass Spectrometry analysis of biochar indicated the presence of alkanes, alkenes, nitriles, fatty acids, esters, amides and aromatic compounds. Number of compounds decreased with increasing temperature, but aromatic compounds increased with increasing temperature. Scanning electron micrographs of biochar prepared at different temperatures indicated micropore formation at lower temperature while increase in the size of pores and disorganization of vessels occurred at increasing temperature. The chemical composition was found to be richer at lower pyrolysis temperature. GC–MS analysis of the bio-oil indicated the presence of phenols, ketones, acids, alkanes, alkenes, nitrogenated compounds, heterocyclics and benzene derivatives.     

Pyrolysis of residual palm oil in spent bleaching clay by modified tubular furnace and analysis of the products by GC–MS

In this study, spent bleaching clay containing 26.6 wt.% of residual palm oil was pyrolyzed using a tubular furnace. Carboxylic acids ranging from C₉-C₁₈ and alkanes ranging from C₁₆-C₄₄ were the major classes of compounds found in the pyrolytic products analyzed using GC-MS. Significant amounts of monoaromatic compounds, alkenes, alcohols, ketones, aldehydes, esters, nitrogenated compounds, and polycyclic aromatic hydrocarbons (PAHs) were found in the bio-oil produced in this study. The bio-oil resulting from the pyrolysis process gave n-hexadecanoic acid as the major compound. Decomposition temperature of the adsorbed oil determined using TGA was found to be in the range of 573-683 K. Topographical and elemental analyses of the clay was done using SEM-EDX. The functional groups were determined using FTIR.     

Understanding the pyrolysis of CCA-treated wood: Part II. Effect of phosphoric acid

The pyrolysis process of chromated copper arsenate-treated wood impregnated with phosphoric acid (2–6 wt.%) has been investigated using a Kugelrohr short-path distillation apparatus. The presence of phosphoric acid is shown to change the overall pyrolysis kinetics and yields of products resulting in a decrease in the amount of volatile products and an increase in the char formation. The yield of levoglucosan was found to decrease in the presence of relatively higher concentrations of phosphoric acid, while the yield of levoglucosenone increased. The pyrolysis of chromated copper arsenate-treated wood in the presence of phosphoric acid gave rise to 22% (on water-free tar basis) levoglucosenone. Such data demonstrates the potential for a new pathway toward the rational utilization of chromated copper arsenate-treated wood waste.     

Effect of alprazolam on rat serum metabolic profiles

We developed a serum metabolomic method by gas chromatography–mass spectrometry (GC–MS) to evaluate the effect of alprazolam in rats. The GC–MS with HP‐5MS (0.25 μm × 30 m × 0.25 mm) mass was conducted in electron impact ionization (EI) mode with electron energy of 70 eV, and full‐scan mode with m /z 50–550. The rats were randomly divided to four groups, three alprazolam‐treated groups and a control group. The alprazolam‐treated rats were given 5, 10 or 20 mg/kg (low, medium, high) of alprazolam by intragastric administration each day for 14 days. The serum samples were corrected on the seventh and fourteenth days for metabolomic study. The blood was collected for biochemical tests. Then liver and brain were rapidly isolated and immersed for pathological study. Compared with the control group, on the seventh and fourteen days, the levels of d ‐glucose, 9,12‐octadecadienoic acid, butanoic acid, l ‐proline, d ‐mannose and malic acid had changed, indicating that alprazolam induced energy metabolism, fatty acid metabolism and amino acid metabolism perturbations in rats. There was no significant difference for alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, urea and uric acid between controls and alprazolam groups. According to the pathological results, alprazolam is not hepatotoxic. Metabolomics could distinguish different alprazolam doses in rats.     

New analytical method for the determination of musks in personal care products by Quick,Easy, Cheap,Effective, Rugged,and Safe extraction followed by GC–MS

Synthetic musks are organic compounds used as fragrance additives and fixative compounds in a diversity of personal care products. A new method based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction followed by GC–MS for the analysis of 12 musks in personal care products was developed and validated. Some experimental parameters, such as total QuEChERS mass, sample mass/solvent volume ratio, type of extraction solvent, as well as salts and sorbents amount were investigated and optimized. The final method involves the musks extraction using acetonitrile, followed by the addition of anhydrous magnesium sulphate and sodium acetate. The clean‐up step was performed using dispersive SPE with primary and secondary amine and octadecyl–silica sorbents. This extraction procedure is fast (about 10 min) when compared to other traditional approaches. The method was robust for the matrices studied and shows a high precision (%RSD < 15%) and accuracy (average recovery of 85%), allowing the detection of musks in minimum concentrations between 0.01 ng/g (galaxolide) and 15.80 ng/g (musk xylene). The developed method was applied to the analysis of 12 samples, which revealed musks concentrations ranging from 2 ng/g (toothpaste) to 882 340 ng/g (perfumed body lotion).     

Exploring the chemical profile of designer drugs by ESI(+) and PSI(+) mass spectrometry—An approach on the fragmentation mechanisms and chemometric analysis

The consumption of design drugs, frequently known as new psychoactive substances (NPS), has increased considerably worldwide, becoming a severe issue for the responsible governmental agencies. These illicit substances can be defined as synthetic compounds produced in clandestine laboratories in order to act as analogs of schedule drugs mimetizing its chemical structure and improving its pharmacological effects while hampering the control and making regulation more complicated. In this way, the development of new methodologies for chemical analysis of NPS drugs is indispensable to determine a novel class of drugs arising from the underground market. Therefore, this work shows the use of high‐resolution mass spectrometry Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR MS) applying different ionization sources such as paper spray ionization (PSI) and electrospray ionization (ESI) in the evaluation of miscellaneous of seized drugs samples as blotter paper (n = 79) and tablet (n = 100). Also, an elucidative analysis was performed by ESI(+)MS/MS experiments, and fragmentation mechanisms were proposed to confirm the chemical structure of compounds identified. Besides, the results of ESI(+) and PSI(+)‐FT‐ICR MS were compared with those of GC–MS, revealing that ESI(+)MS showed greater detection efficiency among the methodologies employed in this study. Moreover, this study stands out as a guide for the chemical analysis of NPS drugs, highlighting the differences between the techniques of ESI(+)‐FT‐ICR MS, PSI(+)‐FT‐ICR MS, and GC–MS.     

Analytical pyrolysis vs. classical wet chemical analysis to assess the decay of archaeological waterlogged wood

The macromolecular complexity of wood limits the possibility of obtaining complete chemical information on its alteration in archaeological objects. This paper compares the results obtained in the characterisation of the components of archaeological wood by a classical wet chemical method and by an instrumental method based on pyrolysis in presence of hexamethyldisilazane coupled with gas chromatography/mass spectrometry, Py(HMDS)–GC/MS. We compare the results obtained with the two methods quantitatively. This enables us to evaluate the efficiency of Py(HMDS)–GC/MS in assessing the chemical composition and the state of conservation of degraded wood. The material analysed consisted of reference sound wood and waterlogged wood from the ?ó?te historical site, located on a small island on Lake Zarańskie in Poland. The samples are from the remains of settlements dating to a period between the 9th and the 12th centuries AD.     

Metabonomic analysis of the anti‐inflammatory effects of volatile oils of Angelica sinensis on rat model of acute inflammation

Metabonomics based on GC‐MS was used to study the possible anti‐inflammatory mechanisms of volatile oils of Angelica sinensis (VOAS) in rats with acute inflammation. Acute inflammation was induced by subcutaneous injection of carrageenan in rats. The levels of prostaglandin E₂ (PGE₂), histamine (HIS) and 5‐hydroxytryptamine (5‐HT) in the inflammatory fluid were detected. Principal component analysis and orthogonal partial least squares‐discriminant analysis models were performed for pattern recognition analysis. After the administration of VOAS, the levels of PGE₂, HIS, and 5‐HT returned to levels observed in normal group. According to GC‐MS analysis, the intervention of VOAS in rats with acute inflammation induced substantial and characteristic changes in their metabolic profiles. Fourteen metabolite biomarkers, namely, lactic acid, malic acid, citric acid, trans‐dehydroandrosterone, aldosterone, linoleic acid, hexadecanoic acid, pregnenolone, octadecenoic acid, myristic acid, l ‐histidine, octadecanoic acid, arachidonic acid (AA) and l ‐tryptophan, were detected in the inflammatory fluid. The levels of all biomarkers either increased or decreased significantly in model groups. VOAS possibly intervened in the metabolic process of inflammation by altering histidine metabolism, tryptophan metabolism, AA metabolism, steroid hormone biosynthesis, fatty acid metabolism and energy metabolism. Metabonomics was used to reflect an organism's physiological and metabolic state comprehensively, and it is a potentially powerful tool that reveals the anti‐acute‐inflammatory mechanism of VOAS. Copyright © 2014 John Wiley & Sons, Ltd.     

Influence of pyrolysis temperature and time on the cellulose fast pyrolysis products: Analytical Py-GC/MS study

Analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was employed to achieve fast pyrolysis of cellulose and on-line analysis of the pyrolysis vapors. Experiments were performed to reveal the effects of pyrolysis temperature and time on the distribution of the pyrolytic products, especially the formation characteristics of eighteen important products. During the fast pyrolysis process, the cellulose started decomposition to form organic volatile products at the set pyrolysis temperature of 400 °C. The pyrolytic products included various anhydrosugars (dominated by the levoglucosan (LG)), anhydrosugar derivatives (mainly the levoglucosenone (LGO), 1,4:3,6-dianhydro-α-d-glucopyranose (DGP), 1,5-anhydro-4-deoxy-d-glycero-hex-1-en-3-ulose (APP) and 1-hydroxy-3,6-dioxabicyclo[3.2.1]octan-2-one (LAC)), furan compounds (typically the 5-hydroxymethyl-furfural (HMF), furfural (FF) and furan (F)), as well as light linear carbonyls (mainly the hydroxyacetaldehyde (HAA) and 1-hydroxy-2-propanone (HA)). These products were generated with different characteristics. The LG was the most important product, it was thermally stable, and its formation was favored at elevated pyrolysis temperature and time. Most of the other products were also enhanced at elevated pyrolytic conditions. However, some products, such as the LGO, were favorable to be produced at low temperatures. Based on these characteristics, discussion was performed on the possible pyrolytic pathways for the formation of the important products.     

LC‐DAD/ESI‐MS/MS study of phenolic compounds in ash (Fraxinus excelsior L. and F. americana L.) heartwood. Effect of toasting intensity at cooperage

The phenolic composition of heartwood extracts from Fraxinus excelsior L. and F. americana L., both before and after toasting in cooperage, was studied using LC‐DAD/ESI‐MS/MS. Low‐molecular weight (LMW) phenolic compounds, secoiridoids, phenylethanoid glycosides, dilignols and oligolignols compounds were detected, and 48 were identified, or tentatively characterized, on the basis of their retention time, UV/Vis and MS spectra, and MS fragmentation patterns. Some LMW phenolic compounds like protocatechuic acid and aldehyde, hydroxytyrosol and tyrosol, were unlike to those for oak wood, while ellagic and gallic acid were not found. The toasting of wood resulted in a progressive increase in lignin degradation products with regard to toasting intensity. The levels of some of these compounds in medium‐toasted ash woods were much higher than those normally detected in toasted oak, highlighting vanillin levels, thus a more pronounced vanilla character can be expected when using toasted ash wood in the aging wines. Moreover, in seasoned wood, we found a great variety of phenolic compounds which had not been found in oak wood, especially oleuropein, ligstroside and olivil, along with verbascoside and isoverbascoside in F. excelsior, and oleoside in F. americana. Toasting mainly provoked their degradation, thus in medium‐toasted wood, only four of them were detected. This resulted in a minor differentiation between toasted ash and oak woods. The absence of tannins in ash wood, which are very important in oak wood, is another peculiar characteristic that should be taken into account when considering its use in cooperage. Copyright © 2012 John Wiley & Sons, Ltd.     

Mechanism Studies of the Conversion of 13C‐Labeled n‐Butane on Zeolite H‐ZSM‐5 by Using 13C Magic Angle Spinning NMR Spectroscopy and GC–MS Analysis

By using ¹³C MAS NMR spectroscopy (MAS=magic angle spinning), the conversion of selectively ¹³C‐labeled n‐butane on zeolite H‐ZSM‐5 at 430–470 K has been demonstrated to proceed through two pathways: 1) scrambling of the selective ¹³C‐label in the n‐butane molecule, and 2) oligomerization–cracking and conjunct polymerization. The latter processes (2) produce isobutane and propane simultaneously with alkyl‐substituted cyclopentenyl cations and condensed aromatic compounds. In situ ¹³C MAS NMR and complementary ex situ GC–MS data provided evidence for a monomolecular mechanism of the ¹³C‐label scrambling, whereas both isobutane and propane are formed through intermolecular pathways. According to ¹³C MAS NMR kinetic measurements, both pathways proceed with nearly the same activation energies (E_a=75 kJ mol^?1 for the scrambling and 71 kJ mol^?1 for isobutane and propane formation). This can be rationalized by considering the intermolecular hydride transfer between a primarily initiated carbenium ion and n‐butane as being the rate‐determining stage of the n‐butane conversion on zeolite H‐ZSM‐5.     

Screening method for phthalate esters in water using liquid-phase microextraction based on the solidification of a floating organic microdrop combined with gas chromatography-mass spectrometry

A simple and efficient liquid-phase microextraction (LPME) technique was developed using directly suspended organic microdrop coupled with gas chromatography–mass spectrometry (GC–MS), for the extraction and the determination of phthalate esters (dimethyl phthalate, diethyl phthalate, diallyl phthalate, di-n-butyl phthalate (DnBP), benzyl butyl phthalate (BBP), dicyclohexyl phthalate and di-2-ethylhexyl phthalate (DEHP)) in water samples. Microextraction efficiency factors, such as nature and volume of the organic solvent, temperature, salt effect, stirring rate and the extraction time were investigated and optimized. Under the optimized extraction conditions (extraction solvent: 1-dodecanol; extraction temperature: 60 °C; microdrop volume: 7 μL; stirring rate: 750 rpm, without salt addition and extraction time: 25 min), figures of merit of the proposed method were evaluated. The values of the detection limit were in the range of 0.02–0.05 μg L⁻¹, while the R.S.D.% value for the analysis of 5.0 μg L⁻¹ of the analytes was below 7.7% (n = 4). A good linearity (r² ≥ 0.9940) and a broad linear range (0.05–100 μg L⁻¹) were obtained. The method exhibited enrichment factor values ranging from 307 to 412. Finally, the designed method was successfully applied for the preconcentration and determination of the studied phthalate esters in different real water samples and satisfactory results were attained.     

Study of the influence of NaOH treatment on the pyrolysis of different leather tanned using thermogravimetric analysis and Py/GC-MS system

This paper presents a study of the influence of a NaOH treatment on leather samples tanned using different tanning agents. Thermogravimetric analysis (TG/DTG) and flash pyrolysis (Py/GC-MS) was carried out on treated samples, and the results were compared with those obtained with the untreated samples. Treatment with sodium hydroxide seemed to decrease the temperature of maximum leather decomposition rate between 4 and 27 °C, depending on the tanning agent, and increased the range of temperatures where leather degradation occurs. From flash pyrolysis experiments, it was found that the volatile products obtained from NaOH-treated samples contain higher amounts of nitrogen compounds than those obtained from untreated samples. The results of a multivariate analysis applied to pyrolytic products obtained in the flash pyrolysis of samples showed greater similarity between the results obtained in all treated samples than between treated and untreated samples produced with the same tanning process.     

Effect of the chemical environment on the light-induced degradation of a photochromic dye in ormosil thin films

The naphthopyran (NP) derivative (3-(2,4-dimethoxyphenyl)-3-(4-methoxyphenyl)-3H-naphtho[2,1-b]pyran) exhibits photochromism in solution or embedded in solid matrices. The molecule suffers a progressive photodegradation upon prolonged irradiation with UV-light, which depends strongly on the solvent or the embedding matrix. The photodegradation of the dye molecules in THF or benzene solutions is much faster than that of the molecules embedded in solid matrices (polymer or ormosil).The organic functional groups incorporated in the network of the ormosil matrix play an important role in the photostability of the dye, as they determine the chemical environment of the dye molecules in the matrix. In this way, the dye embedded in matrices whose inner pore surface is functionalized with phenyl groups exhibits a photostability nine times higher than in unmodified matrices, being their degradation half-life (t_1/2(deg)) 181 h and 21 h, respectively. The photostability of the photochromic dye in the ormosil matrices was also measured as a function of the dye loading, showing higher stability as the amount of dye is increased. The photostability of the dye in photochromic materials is an important issue in sight of the possible applications of these materials, as the performance of the devices involves repeated exposure to UV radiation.     

菥蓂籽挥发油的GC/MS分析

菥蓂(Thlaspi arvenseLinn),又名苏败草、遏蓝菜、苦苦菜、罗汉菜,属双子叶植物药十字花科一年生草本植物,我国大部分地区均有分布,在川西北草原储量较丰富[1]。它既是一种中药材,又是一种可食用野生资源和潜在的油料作物来源。其种子含黑芥子甙(Sinigrin)及34%左右的油脂,味辛     

Gradient elution mode for the troubleshooting of matrix effect on the determination of G004 in different tissues by LC‐MS/MS

A steep gradient elution mode was applied to reduce the risk of matrix effect (ME) for the determination of G004, a novel sulfonylurea hypoglycemic drug, in a tissue distribution study by LC‐MS/MS. The mass spectra of the total‐ion‐current chromatograms combined with the post‐column infusion traces enabled the ‘unseen’ interfering species to be directly detected, and ensured that the chromatography conditions and sample preparation method were adequate to overcome the ME. According to this, a steep gradient elution mode was designed to overcome the intense ME from different tissues. The analysis was performed by monitoring the transitions m/z 558.1 → 419.0 for G004 and m/z 489.3 → 364.1 for glimepiride used as the internal standard. Calibration curves recovered over a range from 0.1 to 10000 ng/mL for seven different tissues. Sex‐related difference was found in the tissue distribution. The drug levels in the tissues of female rats were about two to three times higher than those in male counterparts. The highest level was observed in liver, then in kidney, heart, pancreas, lung and spleen, but no G004 was detected in brain. G004 was slowly eliminated from female rats compared with male rats. There was no long‐term accumulation of G004 in male or female rat tissues. Copyright © 2014 John Wiley & Sons, Ltd.     

Development and validation of a rapid and sensitive assay for the determination of anisodamine in 50 μL of beagle dog plasma by LC–MS/MS

A simple, rapid, high‐throughput, and highly sensitive LC–MS/MS was developed to determine anisodamine in a small volume (50 μL) of beagle dog plasma using atropine sulfate as the internal standard. The analyte and internal standard were isolated from 50 μL plasma samples after a one‐step protein precipitation using Sirocco 96‐well protein precipitation filtration plates. The separation was accomplished on a Hanbon Hedera CN column (100 × 4.6 mm, 5 μm) and the run time was 4 min. A Micromass Quatro Ultima mass spectrometer equipped with an ESI source was operated in the multiple reaction monitoring mode with the precursor‐to‐product ion transitions m/z 306.0→140.0 (anisodamine) and 290.0→123.9 (atropine) used for quantitation. The method was sensitive with a low LOQ of 0.05 ng/mL, and good linearity in the range 0.05–50 ng/mL for anisodamine (r² ≥ 0.995). All the validation data, such as accuracy, intra‐ and interrun precision, were within the required limits. The method was successfully applied to the pharmacokinetic study of anisodamine hydrochloride injection in beagle dogs.