PHYTOCHEMICAL ANALYSIS
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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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产品关联
DOI
PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2021
·
IF 5.455
Jun Liang,Yingying Wang,Xiangcheng Li,Ming Xu,Shaochun Shen,Chuang Liu,Wenhua Fu,Weichuan Tao,Zhiqing Yuan,Zhendong Wang,Weimin Yang
A novel quaternary ammonium hydroxide , p-Xylylene-bis(N-methylpiperidinium hydroxide) (XBMPOH), was prepared and used as an organic structure-directing agent (OSDA) for the syntheses of BEC zeolites . Both Si,Ge- BEC and Al incorporated BEC (Al- BEC ) zeolites were successfully synthesized. In comparison with commonly used OSDA (tetraethylammonium hydroxide (TEAOH)), XBMPOH was more suitable for the crystallization of BEC structure, especially in the Al containing system. Al- BEC zeolites were directly synthesized at lower germanium and OSDA content, in a wider (Si + Ge)/Al ratio range (20 to ∞ vs. 50 to ∞) and shorter time (6 h vs. 12 h). For the first time, Al- BEC zeolites were used as a solid acid to catalyze the alkylation of benzene with 1-dodecene, and showed significant catalytic performance. After an acidic treatment procedure, the catalytic performance was further improved due to the removal of non-framework Al with accompanied exposure of framework Al.
研究领域:
化学工程
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材料科学
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催化化学
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产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2014
·Vol. 90
·期 12
·2186-2194
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IF 2.494
Chao Zhong,Chunming Wang,Fengxue Wang,Honghua Jia,Ping Wei,Yin Zhao
BACKGROUND As one of the most abundant natural resources, lignocellulosic biomass is usually utilized at low efficiencies because of its complicated structure and poor degradability, and pretreatments prior to utilization are therefore considered necessary. To overcome the disadvantages of traditional pretreatments for lignocellulosic biomass, a method based on the application of quaternary ammonium hydroxide was investigated. RESULTS Remarkable structural transformation and compositional changes were detected in pretreated biomass, presenting significant removal of lignin and decreased cellulose crystallinity, which could contribute to enhanced degradability. Significant factors in this process were investigated by single-factor experiment and response surface methodology, and optimum conditions were calculated as: reaction time 7.0 h, temperature 51.6 °C, and concentration of solvent 16.8%. Biomass pretreated under these conditions presented a maximum saccharification yield of 73.71%, which was a 3-fold increase compared with the untreated sample. In addition, the solvent quaternary ammonium hydroxide was recycled five times for biomass pretreatment with high activity retained. CONCLUSIONS Enhanced saccharification efficiency of lignocellulosic biomass was achieved by pretreatment with quaternary ammonium hydroxide. © 2014 Society of Chemical Industry
研究领域:
生物化学
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可再生能源
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Hui Yu,Pian Jin,Fucheng Zhu,Makoto Takafuji,Hirotaka Ihara,Lei Nie,Houmei Liu
The analysis of body fluids (blood, urine, serum, etc .) to accurately detect drug contents has garnered considerable attention in pharmacokinetic and other related studies. Due to the complicated composition of body fluids and low concentration of drugs, efficient implementation of solid phase extraction (SPE) technology is a powerful strategy. This study introduces the preparation of novel π-conjugated polymer modified porous silica (SiO 2 @π-CP) as adsorbent for extraction of quaternary ammonium alkaloids (QAAs). The preparation process of SiO 2 @π-CP is easy and the cost is low. Due to the existing of large conjugate structure and rich polar groups (hydroxyl and amine) in π-CP, SiO 2 @π-CP can form efficient interactions with QAAs (jatrorrhizine, berberine, chelerythrine and sanguinarine as the model analytes). In order to get a better understanding about the adsorption mechanism and process, adsorption kinetics, adsorption isotherms, and thermodynamic studies were conducted. SiO 2 @π-CP was also proven to have outstanding corrosion resistance and reusability. By investigating the main SPE parameters, the SPE method based on SiO 2 @π-CP was developed. Excellent results were obtained, including satisfied limits of detections (0.5–2.0 ng/mL), limits of quantifications (0.5–20.0 ng/mL), linearities (0.5–4000 ng/mL), RSDs of inter-day (0.9%–3.4%) and intra-day (1.7–5.0%). This research highlights the novel SiO 2 @π-CP adsorbent possesses the potential for addressing the enrichment of QAAs in real urine samples.
研究领域:
分析化学
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药物代谢动力学
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DOI
高影响因子
PROCESS BIOCHEMISTRY
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2016
·
IF 2.529
Chao Zhong,Honghua Jia,Ping Wei
Lignocelluloses featuring complicated structure and poor degradability usually require pretreatment before its utilization. In this study, an ultrasonic-assisted pretreatment by using quaternary ammonium hydroxide was introduced to enhance biodegradability of lignocellulosic biomass. The synergistic chemical and mechanical pretreatment were supposed to be responsible for both external surface destruction and internal structure disruption of lignocelluloses. High-efficient lignin removal accompanied with obvious structural (crystallinity) transformation was achieved in the pretreated straws. Process analysis indicated that factors of time, temperature, concentration of solvent, and ultrasound power intensity turned out to be significant for pretreatment, and a 4-fold increased saccharification yield of around 92.4% as compared to untreated straw was obtained from the wheat straw pretreated by 15% solvent at 50 °C for 0.5 h in power intensity 344 W/cm 2 . All results suggest that the combined chemical and mechanical treatment can significantly improve the bio-accessibility of lignocelluloses, leading to the enhanced utilization efficiency.
研究领域:
生物化学
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可再生能源
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
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2016
·Vol. 51
·期 12
·5834-5842
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IF 2.302
Hu Yong,Gu Da Wei,Li Fan,Qi Xiang Chun,Yang Kai Hua,Liu Xun Dao,Li Hong,Zhang Yong Ming
Fluorinated block copolymers poly(2,3,4,5,6-pentafluorostyrene)- b -poly(styrene) (PFS- b -PS) synthesized by atom transfer radical polymerization was functionalized with quaternary ammonium base groups via chloromethylation of PFS- b -PS, followed by reactions with trimethylamine and ion exchange with KOH to prepare anion exchange block polymer electrolytes (AEBPEs). The challenges and limitations during the synthesis are discussed. A comparative study on the chloromethylation of PFS- b -PS with two kinds of chloromethylation agents is carried out. The thermal stability, morphology, and conductivity of the obtained AEBPEs (PFS- b -QAPS(OH)) were investigated by thermogravimetry analysis, differential scanning calorimeter, small-angle X-ray scattering, and AC impedance, respectively.
研究领域:
材料科学
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化学工程
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能源材料
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DOI
高影响因子
Analytical Methods
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2014
·Vol. 7
·期 1
·135-142
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IF 1.938
Houmei Liu,Yong Guo,Xusheng Wang,Yikun Li,Xiaojing Liang,Xia Liu
In this paper, a novel sorbent, double carboxyl silicane modified graphene oxide coated silica has been prepared and used as sorbent for solid-phase extraction of quarternary alkaloids. The synthesized sorbent material was characterized by elemental analysis and field emission scanning electron microscopy. The extraction properties of the developed sorbent were evaluated by four quarternary alkaloids: coptisine chloride, sanguinarine, berberine chloride and chelerythrine. Multiple interactions, i.e., electrostatic, hydrogen bonding and dipole–dipole interactions, take place during the extraction. After the optimization of conditions, several parameters, such as volume of sample loading, pH of sample, pH of eluent and sample loading velocity, were set up. Under the optimal conditions, good linearities with R2 ranging from 0.9990 to 0.9995 were obtained for the four compounds. The LODs were found to be in the range of 1–2 μg L−1, and the LOQs were found to be in the range of 2–5 μg L−1. The recoveries of the four quarternary alkaloids spiked with 5 μg L−1 in human urine samples ranged from 89.1% to 110.6% with RSDs in the range of 2.6–10.4%. The results showed that the new sorbent has excellent extraction capacity for the tested quarternary alkaloids.
研究领域:
分析化学
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药物分析
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产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
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2023
·
IF 6
Rui Peng,Yingying Guo,Jiage Liu,Huiyong Wang,Zhiyong Li,Xiaopeng Xuan,Yang Zhao,Jianji Wang
Metal−organic framework nanosheets (MONs) show promising applications in many fields, but the production of large amounts of high-quality MONs remains a challenge. Here, we report a general liquid-phase stripped approach to exfoliate a benzoic acid linked MOF (Al 2 (OH) 2 TCPP-Co) in water by using quaternary ammonium hydroxides as deprotonation reagent, intercalator and stabilizer simultaneously. It is shown that the stripped yield is high up to 27.5%, the thickness of MONs is mainly 1–3 nm, and the horizontal size is less than one hundred nanometers. The molecular geometry and alkalinity of quaternary ammonium hydroxides play vital roles in the exfoliation of MONs. Moreover, the MONs have been applied as photocatalysts for the conversion of CO 2 to CO in a gas–solid model under UV–visible light illumination without using any photosensitizer and sacrificial agents. The productivity rate of CO is 118.7 μmol g −1 h −1 , which outperforms most of the photocatalysts reported previously. Thus, the liquid phase stripping method reported in this work has great potential in the large-scale production of MONs for efficient photocatalysis of CO 2 reduction in the gaseous phase.
研究领域:
材料科学
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化学
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环境科学
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纳米技术
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产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2024
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IF 12.2
Yu Han,Yan Yang,Yuling Ma,Daxin Liang,Liping Wen,Jun Ma,Wei Wang
As lithium is the cornerstone of green energy development, it is crucial to realize a low environmental impact and efficient lithium extraction process. Ion-sieve adsorption is the most widely used method to extract liquid lithium resources, but this method is only efficient under alkaline conditions for H + and Mg 2+ competing adsorption. Conventional methods are often accompanied by the consumption of quantities of alkali, the generation of solid waste, and the acidification of liquid lithium resources. To address these issues, a selective ion-channel adsorbent was constructed. The composition comprises an ion sieve adsorbent and an organic carrier with a zwitterionic quaternary ammonium base group. This group storages OH - in situ, hinders H + diffusion, slows down Mg 2+ diffusion, and accelerates Li + diffusion by relying on the difference in binding energies, which reduces the competing adsorption and avoids acidification and solid waste generation. The saturated adsorption capacity (21.38 mg/g) and selectivity of the adsorbent are 4.7 and 24 times higher than that of conventional ion-sieve adsorbent under neutral conditions respectively. The dosage of alkali is 1/256 of the traditional method, the effluent remains neutral and no solid waste is generated. This study presents an environmental and effective adsorbent for lithium extraction.
研究领域:
材料科学
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环境科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）