INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2011
·Vol. 36
·期 23
·15266-15272
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IF 4.057
Pei Pei Yuan,Bin Hong Liu,Zhou Peng Li
A comparative study was performed on four LiBH 4 -based hydrogen storage composites 2LiBH 4 + MgX 2 and 6LiBH 4 + CaX 2 (X = H and F). The composites with fluorides and those with corresponding hydrides exhibited similar hydrogen storage properties. The dehydrogenation of 2LiBH 4 + MgF 2 demonstrated a strong dependence on the hydrogen back pressure , similar to that of 2LiBH 4 + MgH 2 . The reversible hydrogen storage of 2LiBH 4 + MgF 2 was achieved under a back pressure of 5 bar at 450 °C. Dehydrogenation under lower H 2 pressures resulted in the production of Mg and thus a partial reversibility. In contrast, both 6LiBH 4 + CaH 2 and 6LiBH 4 + CaF 2 revealed reversible hydrogen storage properties regardless of the hydrogen back pressure. The structural difference between MgB 2 and CaB 6 may account for the observed differences in hydrogen storage properties of the Mg- and Ca-containing LiBH 4 reactive composites.
研究领域:
材料科学
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能源化学
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固态储氢
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无机化学
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功能材料
✓ 已验证
DOI
高影响因子
JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
·
2017
·
IF 3.255
Yang Huang,Ying Feng,Guangyun Tang,Minyi Li,Tingting Zhang,Marianne Fillet,Jacques Crommen,Zhengjin Jiang
Flavonoids from plants always show a wide range of biological activities. In the present study, a rapid and highly efficient supercritical fluid chromatography (SFC) method was developed for the separation of 12 flavonoids. After careful optimization, the 12 flavonoids were baseline separated on a ZORBAX RX-SIL column using gradient elution. A 0.1% phosphoric acid solution in methanol was found to be the most suitable polar mobile phase component for the separation of flavonoids. From the viewpoint of retention and resolution, a backpressure of 200 bar and a temperature of 40 °C were shown to give the best results. Compared with a previously developed reverse phase liquid chromatography method, the SFC method could provide flavonoid separations that were about three times faster, while maintaining good peak shape and comparable peak efficiency. This SFC method was validated and applied to the analysis of five flavonoids (kaempferol, luteolin, quercetin, luteoloside, buddleoside) present in Chrysanthemum morifolium Ramat. from different cultivars (Chuju, Gongju, Hangju, Boju). The results indicated a good repeatability and sensitivity for the quantification of the five analytes with RSDs for overall precision lower than 3%. The limits of detection ranged from 0.73 to 2.34 μg/mL, while the limits of quantification were between 2.19 and 5.86 μg/mL. The method showed that SFC could be employed as a useful tool for the quality assessment of Traditional Chinese medicines (TCMs) containing flavonoids as active components.
研究领域:
分析化学
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生药学
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药物分析
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2022
·
IF 4.601
Yanyan Wang,Liuqian Bao,Jiajing Sun,Yuanyuan Ding,Jiasheng Shi,Zhengyu Duan,Zhiyong Chen
Fluorous affinity chromatography has received growing attention in separation and purification of fluoro compounds, but the wettability of the fluorinated stationary phases is seldom noticed. Here, we construct a series of micro-sized fluorine-containing microspheres by solvothermal precipitation polymerization. The fluorinated microspheres could be obtained with narrow size distribution at even high monomer loading of 15 wt%. Through alternating fluoro monomer, both the particle size and the wettability of the microsphere array could be tuned. Among them, the poly(divinylbenzene -dodecafluoroheptyl methacrylate), P(DVB-DFHMA), microsphere (6.1 μm) arrays displays superhydrophobicity with 153.2° water contact angle. The P(DVB-DFHMA) fluorinated microspheres (7.58% fluorine content) can be packed into steel-less columns as stationary phase for high-performance liquid chromatography. The retention mechanism of the fluorinated column is proven to be the specific fluorine-fluorine interaction. Compared to the commercial C18 silica column, the fluorinated column can completely separate fluorine-containing compounds under high water content mobile phase, including small fluoro molecules and fluoro macromolecules, at much lower back pressure by fluorous affinity.
研究领域:
化学
·
材料科学
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分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Analytical Methods
·
2020
·Vol. 12
·期 21
·2727-2734
·
IF 2.596
Yuhong Zhou,Qian Liang,Zhilun Zhang,Zhaodi Wang,Mingxian Huang
A hybrid silica monolith containing vinyl groups was synthesized by a sol–gel method, and then ground and treated, yielding silica particles with a 3–5 μm particle size and a 10–20 nm pore size. Cellulose derivatives containing 3,5-dimethylphenylcarbamate groups and methacrylate groups regioselectively were then immobilized onto the surface of the above particles by the thiol–ene click reaction using an alkanedithiol as the crosslinking agent, thus forming a solvent-resisting crosslinked network structure attached onto the surface of the particles. The immobilization degree was more than 80%, and the back pressure of the chiral stationary phase (CSP) packed column was relatively low and was maintained at around 3.0 MPa. The as-prepared CSPs were shown to be able to effectively separate various enantiomers with different mobile phases.
研究领域:
分析化学
·
材料科学
·
色谱学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Huiying Zuo,Yun Guo,Wenjie Zhao,Kai Hu,XiaoYu Wang,Lijun He,Shusheng Zhang
The unique properties of covalent triazine-based organic framework/polymers, including large surface area, hydrophilic–lipophilic-balanced adsorption, and economical preparation, make it a promising candidate as a stationary phase for high-performance liquid chromatography. However, irregular shapes and wide size distributions of such particles hinder column packing, resulting in a low column efficiency or a high back pressure. Herein, we describe the fabrication of SiO2@ covalent triazine-based organic polymer (CTP) core–shell microspheres with a distinct sphere-coating-sphere appearance using aminosilica as the supporting substrate to grow the CTP shell. By adjusting the amount of reactants, the thickness of the CTP shell, which consists of triazine and 1,3,5-triphenylbenzene monomers, was easily controlled. The developed core–shell microspheres were characterized via scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, solid-state 13C nuclear magnetic resonance analysis, and N2 adsorption experiments. The synergism of the triazine and aromatic moieties on CTP provides the new stationary phase with multiple retention mechanisms, including hydrophobic, π–π, electron donor–acceptor, hydrogen-bonding interactions, and so forth. On the basis of these interactions, successful separation and higher shape selectivity were achieved among several analytes that vary in polarity under both reversed-phase and hydrophilic interaction liquid chromatography conditions. Therefore, SiO2@CTP microspheres combine the advantages of good column packing properties of the uniform monodisperse silica microspheres and the recognition performance of CTP, generating flexible selectivity and application prospect for both hydrophilic and hydrophobic analytes.
研究领域:
材料科学
·
分析化学
·
化学工程
·
色谱学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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