COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2019
·
IF 3.131
Panpan Fan,Yuxian Wang,Jian Shen,Ling Jiang,Wei Zhuang,Yuwang Han,Hongman Zhang
The self-assembly properties of long-chain C 18 fatty acids salts have good application in the field of environmental protection, drug control relieve, renewable energy and so on. Their degree of unsaturation is varied from saturated, monounsaturated to polyunsaturated fatty acids , which influence their self-assembly behaviors. Moreover, different external stimuli can also affect different self-assembly behaviors. In this work, three different fatty acids (stearic acid, C 18:0 ; oleic acid , C 18:1 ; linoleic acid , C 18:2 ) were chosen as the building blocks to self-assemble with arginine, a basic amino acid . The phase behaviors of ion-pairing systems affected by pH, temperature and solvent were investigated based on diagrams in more detail. The rich phase transition was observed through the characterization by cryogenic-transmission electron microscopy (cryo-TEM), polarizing microscopy , particle size analysis and rheological properties. We hope that the phase transition (self-assembly behaviors) controlled by these external conditions may provide a good guide for many related fields.
研究领域:
材料科学
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生物化学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Ziyuan Xiu,Feng Wei,Xin Zhou,Xiaojun Han
Achieving high ammonia yield and Faraday efficiency is a long-sought-after goal in electrochemical N 2 fixation. Yet, the competitive hydrogen evolution in nitrogen reduction process and the low local concentration of nitrogen on the working electrode still limited the electrocatalytic performance. In the present contribution, a Fe-MoSe 2 nanosheet functioned with C18-thiol as a nano-hydrophobic surface was rationally constructed, which efficiently facilitated the three-phase contact of gas (N 2 ), liquid (H 2 O electrolyte), and solid (electrocatalyst). The fabrication of modified hydrophobic surface not only overcame the mass transfer limitation of N 2 and increased the local concentration of N 2 molecules on the catalyst, but also reduced the proton contact with electrocatalyst to inhibit HER. The three-phase electrocatalytic system achieved a high NH 3 yield of 34.75 μg h −1 mg −1 and outstanding Faraday efficiency of 23.31%. The adsorption and activation processes during NRR process were systematically investigated by the combination of experimental results and density function theory (DFT) simulations.
研究领域:
材料科学
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电化学
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催化反应
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高影响因子
FOOD RESEARCH INTERNATIONAL
·
2024
·
IF 7
Mengzi Nie,Jiaxin Li,Ran Lin,Xue Gong,Bin Dang,Wengang Zhang,Xijuan Yang,Lili Wang,Fengzhong Wang,Li-Tao Tong
In this study, five C18 fatty acids (FA) with different numbers of double bonds and configurations including stearic acid (SA), oleic acid (OA), elaidic acid (EA), linoleic acid (LA), and α-linolenic acid (ALA), were selected to prepare highland barely starch (HBS)-FA complexes to modulate digestibility and elaborate the underlying mechanism. The results showed that HBS-SA had the highest complex index (34.18 %), relative crystallinity (17.62 %) and single helix content (25.78 %). Furthermore, the HBS-C18 FA complexes were formed by EA (C18 FA with monounsaturated bonds) that had the highest R 1047/1022 (1.0509) and lowest full width at half-maximum (FWHM, 20.85), suggesting good short-range ordered structure. Moreover, all C18 FAs could form two kinds of V-type complexes with HBS, which can be confirmed by the results of CLSM and DSC measurements, and all of them showed significantly lower digestibility. HBS-EA possessed the highest resistant starch content (20.17 %), while HBS-SA had the highest slowly digestible starch content (26.61 %). In addition, the inhibition of HBS retrogradation by fatty acid addition was further proven, where HBS-SA gel firmness (37.80 g) and aging enthalpy value were the lowest, indicating the most effective. Overall, compounding with fatty acids, especially SA , could be used as a novel way to make functional foods based on HBS.
研究领域:
食品科学
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营养学
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DOI
PubMed
高影响因子
REVIEWS IN ANALYTICAL CHEMISTRY
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2024
·Vol. 43
·期 1
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IF 3.6
Xiaoxi Si,Yu Tian,Shufang Xu,Chunbo Liu,Zhenjie Li,Ji Yang,Ying Guan,Yangzhou Xie,Xiaoqing Shi,Zhigang Xu,Zhihua Liu
Alkaloid enantiomers have different physiological and pharmacological effects, and different chiral compositions have a large impact on cigarette sensory and use safety. Studying the effects of different configurations of alkaloid enantiomers on cigarette sensory is important for the development of tobacco products, but the chiral separation of alkaloid enantiomers has become the core problem. Here, the application of a C18 column coupled with a polysaccharide-based chiral column to separate and detect four pairs of alkaloid enantiomers in tobacco and cigarette smoke of different brands was investigated. Results showed that the tandem technology of the two columns enabled the baseline separation of four pairs of alkaloid enantiomers. The resolution of enantiomers of alkaloids in different tobacco samples differed in content and ratio, showing different chiral distribution characteristics. According to the different distribution characteristics of alkaloid enantiomers, tobacco samples of different brands can be distinguished and real cigarettes can be identified.
研究领域:
分析化学
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烟草科学
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药物化学
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DOI
高影响因子
PHYTOCHEMICAL ANALYSIS
·
2017
·Vol. 28
·期 4
·332-343
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IF 2.292
Qing Wang,Yao Long,Lin Yao,Mao Ye,Li Xu
Introduction Traditional methods for isolating and purifying quaternary ammonium alkaloids from Coptis chinensis do not discriminate the target alkaloids from co-extractives. Mixed-mode analytical chromatography has the potential to improve the separation of analytes in more complex extracts and, when used in a solid-phase extraction mode, improve the purity of isolated compounds. Objective To examine the high-performance liquid chromatographic separation capabilities of a mixed-mode, silica-based adsorbent and its application to the purification of quaternary ammonium alkaloids from Coptis chinensis based on solid-phase extraction. Methodology The C18-COOH silica was prepared via “thiol-ene” click chemistry. Its chromatographic performance was firstly investigated. It was employed as the solid-phase extraction sorbent to purify quaternary ammonium alkaloids. Results Hydrophobic, attractive/repulsive electrostatic and ion-exchange interactions were demonstrated to be the possible retention mechanisms of a C18-COOH silica stationary phase, which could separate analytes of various properties. In addition, to purify quaternary ammonium alkaloids from Coptis chinensis, the solid-phase extraction approach based on the C18-COOH silica provided a slightly higher purification efficiency (6.7%) than an alkaloid-salt precipitation protocol (5.3%). The method had satisfactory reproducibility, re-using the same solid-phase extraction column three times, with relative standard deviations ranging from 1.99% to 8.02% for the six target alkaloids. Conclusion A multi-functionalised silica was synthesised via “click chemistry”. As the high-performance liquid chromatographic stationary phase, the C18-COOH silica could be operated in trimodal reversed-phase/weak cation exchange/hydrophilic interaction mode. The C18-COOH silica also exhibited potential as solid-phase extraction sorbent in the purification of quaternary ammonium alkaloids from complex matrices. Copyright © 2017 John Wiley & Sons, Ltd.
研究领域:
药学
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分析化学
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PubMed
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2020
·Vol. 412
·期 6
·1365-1374
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IF 3.637
Luo Qiurong,Ren Xiujun,Wei Siping,Zheng Yunchao,Gao Die,Fu Qifeng,Xia Zhining,Wang Lujun
Molybdenum disulfide quantum dots (MoS 2 QDs) were chosen as a functional two-dimensional material to improve the separation performance of a traditional C18 column. In this work, MoS 2 QDs were synthesized by the combination of sonication and solvothermal treatment of bulk MoS 2 . The prepared MoS 2 QDs were characterized by transmission electron microscope (TEM), Zeta potential measurement, UV-visible absorption and fluorescence spectroscopy. Then, a novel MoS 2 QDs embedded C18 (Sil-MoS 2 -C18) stationary phase was prepared for performing mixed-mode liquid chromatography. The results of elemental analysis (EA), thermogravimetric analysis (TGA), Fourier transform infrared spectrometry (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and Brunauer-Emmett-Teller (BET) measurements indicated the stationary phase was prepared successfully. Five types of compounds including alkylbenzenes, polycyclic aromatic hydrocarbons (PAHs), nucleosides and nucleobases, anilines and flavonoids were utilized to evaluate reversed phase, weak cation exchange and hydrophilic interaction of the new column. To a certain extent, the column could achieve separation for different properties of samples on one column, with less organic solvent and shorter time than conventional alkyl and amino columns. Furthermore, the mechanism for separation was studied by investigating effects of mobile phase composition and pH on retentions. In summary, the Sil-MoS 2 -C18 stationary phase was deemed able to serve the performance of various types of phases, which revealed the prepared mixed-mode column could be potentially applied for the analysis of complex samples.
Graphical abstract
研究领域:
分析化学
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材料科学
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PubMed
高影响因子
ANALYTICA CHIMICA ACTA
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2015
·
IF 4.513
Qing Wang,Mao Ye,Li Xu,Zhi-guo Shi
A mixed-mode chromatographic packing material, C18 and diol groups modified silica (C18-Diol), was prepared with controllable hydrophobicity and hydrophilicity . It demonstrated excellent aqueous compatibility and stability in aqueous mobile phase ; compared to the traditional C18 column, improved peak shape of basic analytes was also obtained. Additionally, it exhibited both reversed-phase liquid chromatographic (RPLC) and hydrophilic interaction chromatographic (HILIC) performance; the analyte separation scope was thus enlarged, demonstrated by simultaneous separation of twenty acids, bases and neutrals. More interestingly, a novel on-line two-dimensional liquid chromatography on the single column (2D-LC-1C) was established by modifying the high performance liquid chromatographic instrument only with the addition of an extra six-port two-position valve. The early co-eluted components of the extract of Lonicera japonica on the 1st-dimension (RPLC) were collected for the online re-injection to the 2nd-dimension (HILIC) by conveniently varying the mobile phase components. Six more peaks were obtained. The established system was simple, easy operation and low cost, which had advantages in analyzing complicated samples.
研究领域:
分析化学
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药物分析
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色谱技术
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DOI
PubMed
高影响因子
ANALYTICAL SCIENCES
·
2018
·Vol. 34
·期 4
·445-451
·
IF 1.355
Zhang Xuemeng,Li Hengye,Zhang Lin,Kong Fenying,Fan Dahe,Wang Wei
Reduced imine cage (RCC3) was first adopted for the preparation of porous organic cage embedded C18 amide silica stationary phase for high performance liquid chromatography. The prepared stationary phase was characterized by scanning electron microscope (SEM) and Fourier transformation infrared spectrum (FT-IR). Its chromatographic performance under reversed-phase mode was investigated in detail and compared with that of an ODS column. Multiple interactions, including hydrophobic interaction, π-π interactions, electrostatic interactions and hydrogen bonding, were involved due to the synergism of the C18 chain and RCC3. The column showed typical methylene selectivity and enhanced aromatic selectivity for nonpolar analytes while demonstrating high selectivity for polar analytes. In addition, the stationary phase showed the capability of separation of polar and hydrophilic compounds under per aqueous liquid chromatography mode (PALC), providing a green and economical way for the separation of polar and hydrophilic compounds. These results indicated the great application potential of the prepared stationary phase in the analysis of complex samples.
研究领域:
分析化学
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材料科学
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DOI
PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHIC SCIENCE
·
2024
·
IF 1.5
Liang Shan-Yan,Xu Xiao-Min,Wang Peng,Ye Ming-Li,Zhang Shui-Feng,Zhao Yong-Gang
Novel C18-functionalized magnetic nanomaterials; i.e., C18@poly-styrene-divinylbenzene-glycidyl methacrylate-Fe3O4 (C18@PS-DVB-GMA-Fe3O4) have been synthesized by using N, N-dimethyloctadecylamine as modifying agent, which could be beneficial to remove the blood phospholipids. The C18@PS-DVB-GMA-Fe3O4 nanoparticles have been used and evaluated in the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) procedure for human plasma prior to the analysis of propofol by supercritical fluid chromatography (SFC). In the QuEChERS procedure, human plasma samples are directly mixed with extraction solvent and C18@PS-DVB-GMA-Fe3O4 nanoparticles, and the extraction and cleanup procedures have been accomplished simultaneously. The SFC separation was performed with a C18 column (Thermo Scientific™ Acclaim™ 120, 250 × 4. 6 mm, 5 μm) within 5 min, using thymol as the internal standard. Supercritical carbon dioxide was used as the mobile phase with methanol as the cosolvent at the flow rate of 1.0 mL/min. The column temperature was 38°C, and detection wavelength was 275 nm. A good linearity was obtained among the propofol concentration range of 0.5–10 mg/L (R2 = 0.9997) with the limit of detection of 0.17 mg/L. Recoveries were in the range of 76.5–91.9%, with RSD less than 7.9%. These results suggested that method is convenient, rapid with high accuracy and little matrix effect, and suitable for rapid determination of propofol plasma concentration.
研究领域:
分析化学
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医学
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PubMed
高影响因子
Nanomaterials
·
2023
·Vol. 13
·期 6
·1111
·
IF 5.3
Wen-Xin Liu,Wei-Na Zhou,Shuang Song,Yong-Gang Zhao,Yin Lu
A new type of magnetic nanomaterial with Fe3O4as the core and organic polymer as the shell was synthesized by seed emulsion polymerization. This material not only overcomes the problem of insufficient mechanical strength of the organic polymer, it also solves the problem that Fe3O4is prone to oxidation and agglomeration. In order to make the particle size of Fe3O4meet the requirement of the seed, the solvothermal method was used to prepare Fe3O4. The effects of the reaction time, amount of solvent, pH value, and polyethylene glycol (PEG) on the particle size of Fe3O4were investigated. In addition, in order to accelerate the reaction rate, the feasibility of preparing Fe3O4by microwave was studied. The results showed that under the optimum conditions, the particle size of Fe3O4could reach 400 nm and had good magnetic properties. After three stages of oleic acid coating, seed emulsion polymerization, and C18 modification, the obtained C18-functionalized magnetic nanomaterials were used for the preparation of the chromatographic column. Under optimal conditions, stepwise elution significantly shortened the elution time of sulfamethyldiazine, sulfamethazine, sulfamethoxypyridazine, and sulfamethoxazole while still achieving a baseline separation.Keywords:solvothermal method;chromatographic packing materials;magnetic Fe3O4particles;C18-functionalized magnetic nanomaterials
研究领域:
化学
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材料科学
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分析化学
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PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2020
·
IF 4.049
Jingqiu Zhou,Xiujun Ren,Qiurong Luo,Die Gao,Qifeng Fu,Di Zhou,Fengjiao Zu,Zhining Xia,Lujun Wang
A novel reversed-phase/hydrophilic interaction/ion-exchange (RPLC/HILIC/IEC) and chiral recognition mixed-mode stationary phase material was synthesized using 3-n-octadecyl-1-vinylimidazolium bromide and 6-(1-allylimidazolium)-cyclodextrin tosylate as functional monomers. After identifications of intermediates and stationary phase materials using nuclear magnetic resonance analysis, Fourier transform infrared spectrometer, element analysis and thermogravimetric analysis, the synthesized Sil-VMBD material was packed into an empty column under high pressure. The mixed-mode retention performance was researched by hydrophobic, hydrophilic and ionic compounds. And the retention mechanism of the multi-mode stationary phase was studied via changing the mobile phase composition and pH value. Moreover, the enantiomers of 1-phenyl-1-propanol, warfarin and styrene oxide were separated rapidly under reverse-phase mode. Fast enantioseparation of ibuprofen and ketoprofen were obtained within 4 min under polar organic mode. The experimental results show that the as-prepared mixed-mode column possesses reversed-phase, hydrophilic and ion-exchange interactions with various analytes, and these interactions also enable the stationary phase with multi-mode and chiral separation abilities.
研究领域:
分析化学
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色谱技术
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材料科学
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PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2011
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IF 4.194
Yun Li,Xin Xie,Milton L. Lee,Jiping Chen
Hydrophilic C18 monolithic polymer sorbents were synthesized for use in solid phase extraction (SPE) and in capillary liquid chromatography (LC). The approach involved incorporating both hydrophobic and hydrophilic monomers into a monolithic material, by copolymerization of stearyl methacrylate (SMA), poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) and ethylene dimethacrylate (EDMA) in the presence of selected porogens, to produce translucent mesoporous monolithic materials in bulk (SPE) or white macroporous monoliths inside fused silica capillary columns (capillary LC). A capillary column containing one of the hydrophilic C18 monoliths (i.e. poly(SMA-co-PEGMEMA-co-EDMA) with 15% (w/w) PEGMEMA) demonstrated nearly 35% reduction in retention of polycyclic aromatic compounds and greater than 40% increase in retention of phenols compared to a hydrophobic C18 monolithic column. In addition, the hydrophilic monolith demonstrated significantly improved resolution of phenols. Similar monolithic materials prepared in bulk were ground and sieved to obtain 45–65 μm particles with desired rigidity for SPE. To achieve optimum extraction performance for phenols, several parameters, including sample pH and volume, and eluent type and volume, were investigated. Under optimized experimental conditions, the method demonstrated good sensitivity (1.6 ng/mL LOD) and linearity ( R 2 > 0.97 for 10–200 ng/mL). Again, incorporation of 15% (w/w) PEGMEMA in the monolith increased the extraction efficiency of phenols in water from approximately 20% to 67–92% compared to a hydrophobic C18 monolithic material. Increased wettability of the sorbent by the aqueous sample matrix and the presence of hydrogen-bonding interactions are responsible for the improved retention of polar compounds.
研究领域:
分析化学
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材料科学
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PubMed
高影响因子
危险品化学品经营许可证（带存储）