排序方式: 共有35条查询结果,搜索用时 15 毫秒
1.
采用具有超高分辨率的负离子电喷雾-傅立叶变换离子回旋共振质谱(ESI FT-ICR MS)分析了储层岩石抽提物中的石油酸及中性氮化物的分子组成,得到了抽提物中杂原子化合物类型分布、等效双键数(Double bonds equivalent,DBE)及碳数分布特征。研究结果表明,储层抽提物中含有多达16种不同杂原子类型的化合物,包括N1、N1O1、N1O2、N1O3、N1S1、N1S2、N2、N2S1、O1、O1S1、O2、O2S1、O1S2、O2S2、O3和O4,其中N1、N1S1、O2及O2S1类具有较高的相对丰度。抽提物中的N1类化合物以咔唑和苯并咔唑类化合物为主;N1S1类化合物以C2~C8烷基取代的咔唑并苯并噻吩类化合物为主;O2类化合物主要为1~2环环烷酸,其次还在抽提物中鉴别出具有较高相对丰度的DBE为5和6的O2类化合物;而O2S1类化合物中以DBE为7和8的O2S1具有最高的相对丰度。 相似文献
2.
采用沉淀法和色谱分离法将渤海某油田稠油分离成沥青质、胶质、剩余分3个组分。采用负离子电喷雾技术(ESI)结合高分辨傅立叶变换离子回旋共振质谱仪(FT-ICR MS)研究了该稠油及各组分的分子组成。结果表明,剩余分中有较少的极性杂原子化合物能被负离子ESI电离,如N_1,N_1O_1,O_1和O_2类,其等效双键数(DBE)较小。胶质和原油中极性化合物有相同的杂原子类型,包括N_1,N_1O_1,N_1O_2,N_2,N_2O_2S_1,O_1,O_2,其中胶质和原油中N_1,O_1,O_2类化合物的DBE-碳数分布图相似。沥青质中富集高缩合度且多杂原子的酸性化合物,如含杂原子N_,S的氧化程度高的化合物(N_2O_1,N_1O_3,S_1O_3)及O_3类化合物,这些物质具有较高的界面活性,易吸附在界面上促进界面张力降低和增强界面膜强度,从而有利于乳状液稳定存在。N_1O_1,N_1O_2,N_1O_3类化合物,N_2O_1类化合物可能分别是N_1化合物,N_2化合物的氧化降解产物;随着氧化降解程度增加,降解产物的极性明显增强。 相似文献
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Mattia Spano Alessandro Maccelli Giacomo Di Matteo Cinzia Ingallina Mariangela Biava Maria Elisa Crestoni Jean-Xavier Bardaud Anna Maria Giusti Alessia Mariano Anna Scotto DAbusco Anatoly P. Sobolev Alba Lasalvia Simonetta Fornarini Luisa Mannina 《Molecules (Basel, Switzerland)》2021,26(17)
The metabolite profile of fresh Goji berries from two cultivars, namely Big Lifeberry (BL) and Sweet Lifeberry (SL), grown in the Lazio region (Central Italy) and harvested at two different periods, August and October, corresponding at the beginning and the end of the maturation, was characterized by means of nuclear magnetic resonance (NMR) and electrospray ionization Fourier transform ion cyclotron resonance (ESI FT-ICR MS) methodologies. Several classes of compounds such as sugars, amino acids, organic acids, fatty acids, polyphenols, and terpenes were identified and quantified in hydroalcoholic and organic Bligh-Dyer extracts. Sweet Lifeberry extracts were characterized by a higher content of sucrose with respect to the Big Lifeberry ones and high levels of amino acids (glycine, betaine, proline) were observed in SL berries harvested in October. Spectrophotometric analysis of chlorophylls and total carotenoids was also carried out, showing a decrease of carotenoids during the time. These results can be useful not only to valorize local products but also to suggest the best harvesting period to obtain a product with a chemical composition suitable for specific industrial use. Finally, preliminary studies regarding both the chemical characterization of Goji leaves generally considered a waste product, and the biological activity of Big Lifeberry berries extracts was also investigated. Goji leaves showed a chemical profile rich in healthy compounds (polyphenols, flavonoids, etc.) confirming their promising use in the supplements/nutraceutical/cosmetic field. MG63 cells treated with Big Lifeberry berries extracts showed a decrease of iNOS, COX-2, IL-6, and IL-8 expression indicating their significant biological activity. 相似文献
4.
A. Dretzke H. Backe G. Kube W. Lauth W. Ludolphs A. Morbach M. Sewtz 《Hyperfine Interactions》2001,132(1-4):497-500
Heavy element chemistry is related to the fundamental interest that lies in exploring the upper limits of the periodic table.
Chemical properties of the heaviest elements have already been studied at single atoms in aqueous solutions and in the gas
phase up to an atomic number Z = 107. These techniques allow to study nuclides with half lives as short as about 1 s. Next generation chemistry experiments
could be envisaged with an ion trap technique already developed for stable isotopes. At very low production rates in the order
of 1 per 100 s and/or half lives as short as about 10 ms, the ion-molecule reactions can be studied in a buffer gas cell,
in which the heavy elements are stopped and thermalize with a high probability as singly charged ions. Ion-molecule reactions
with well defined buffer gas admixtures, as, e.g., O2, H2O, CH4, CO2, are identified by mass selective detection.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
Mass spectrometry (MS) is extensively used for the identification and sequencing of nucleic acids but has so far seen limited
use for characterization of their higher order structures. Here, we have applied a range of different tandem mass spectrometry
techniques, including electron detachment dissociation (EDD), infrared multiphoton dissociation (IRMPD), activated ion (AI)
EDD, and EDD/IRMPD MS3, in a Fourier transform ion cyclotron resonance mass spectrometer to the characterization of three isomeric 15mer DNAs with
different sequences and predicted solution-phase structures. Our goal was to explore whether their structural differences
could be directly probed with these techniques. We found that all three 15mers had higher order structures in the gas phase,
although preferred structures were predicted for only two of them in solution. Nevertheless, EDD, AI EDD, and EDD/IRMPD MS3 experiments yielded different cleavage patterns with less backbone fragmentation for the more stable solution-phase structure
than for the other two 15mers. By contrast, no major differences were observed in IRMPD, although the extent of backbone cleavage
was higher with that technique for all three 15mers. Thus, experiments utilizing the radical ion chemistry of EDD can provide
complementary structural information compared to traditional slow heating methods, such as IRMPD, for structured nucleic acids. 相似文献
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A Comparative Study of Pyrolysis Liquids by Slow Pyrolysis of Industrial Hemp Leaves,Hurds and Roots
Ayobami Salami Jorma Heikkinen Laura Tomppo Marko Hyttinen Timo Keklinen Janne Jnis Jouko Vepslinen Reijo Lappalainen 《Molecules (Basel, Switzerland)》2021,26(11)
This study assessed the pyrolysis liquids obtained by slow pyrolysis of industrial hemp leaves, hurds, and roots. The liquids recovered between a pyrolysis temperature of 275–350 °C, at two condensation temperatures 130 °C and 70 °C, were analyzed. Aqueous and bio-oil pyrolysis liquids were produced and analyzed by proton nuclear magnetic resonance (NMR), gas chromatography–mass spectrometry (GC-MS), and atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (APPI FT-ICR MS). NMR revealed quantitative concentrations of the most abundant compounds in the aqueous fractions and compound groups in the oily fractions. In the aqueous fractions, the concentration range of acetic acid was 50–241 gL−1, methanol 2–30 gL−1, propanoic acid 5–20 gL−1, and 1-hydroxybutan-2-one 2 gL−1. GC-MS was used to compare the compositions of the volatile compounds and APPI FT-ICR MS was utilized to determine the most abundant higher molecular weight compounds. The different obtained pyrolysis liquids (aqueous and oily) had various volatile and nonvolatile compounds such as acetic acid, 2,6-dimethoxyphenol, 2-methoxyphenol, and cannabidiol. This study provides a detailed understanding of the chemical composition of pyrolysis liquids from different parts of the industrial hemp plant and assesses their possible economic potential. 相似文献
10.
Renfrow MB Mackay CL Chalmers MJ Julian BA Mestecky J Kilian M Poulsen K Emmett MR Marshall AG Novak J 《Analytical and bioanalytical chemistry》2007,389(5):1397-1407
IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis. In IgAN, IgA1 molecules with incompletely galactosylated
O-linked glycans in the hinge region (HR) are present in mesangial immunodeposits and in circulating immune complexes. It is
not known whether the galactose deficiency in IgA1 proteins occurs randomly or preferentially at specific sites. We have previously
demonstrated the first direct localization of multiple O-glycosylation sites on a single IgA1 myeloma protein by use of activated ion-electron capture dissociation (AI-ECD) Fourier
transform ion cyclotron resonance (FT-ICR) tandem mass spectrometry. Here, we report the analysis of IgA1 O-glycan heterogeneity by use of FT-ICR MS and liquid chromatography FT-ICR MS to obtain unbiased accurate mass profiles of
IgA1 HR glycopeptides from three different IgA1 myeloma proteins. Additionally, we report the first AI-ECD fragmentation on
an individual IgA1 O-glycopeptide from an IgA1 HR preparation that is reproducible for each IgA1 myeloma protein. These results suggest that future
analysis of IgA1 HR from IgAN patients and normal healthy controls should be feasible. 相似文献