MOLECULES
·
2023
·Vol. 28
·期 5
·2415
·
IF 4.6
Ao Xu,Yunlin Xue,Yuyu Zeng,Jing Li,Huiling Zhou,Zhen Wang,Yin Chen,Hui Chen,Jian Jin,Tao Zhuang
Furosemide is a widely used loop diuretic in the treatment of congestive heart failure and edema. During the preparation of furosemide, a new process-related impurity G in the levels ranging from 0.08% to 0.13% was detected in pilot batches by a new high performance liquid chromatography (HPLC) method. The new impurity was isolated and characterized by comprehensive analysis of FT-IR, Q-TOF/LC-MS, 1D-NMR (1H,13C, and DEPT), and 2D-NMR (1H-1H-COSY, HSQC, and HMBC) spectroscopy data. The possible formation pathway of impurity G was also discussed in detail. Moreover, a novel HPLC method was developed and validated for the determination of impurity G and the other six known impurities registered in the European Pharmacopoeia as per ICH guidelines. The HPLC method was validated with respect to system suitability, linearity, the limit of quantitation, the limit of detection, precision, accuracy, and robustness. The characterization of impurity G and the validation of its quantitative HPLC method were reported for the first time in this paper. Finally, the toxicological properties of impurity G were predicted by the in silico webserver ProTox-II.Keywords:furosemide;process-related impurity;characterization;Q-TOF/LC–MS and NMR;method validation
研究领域:
药物化学
·
分析化学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2020
·
IF 5.065
Shengbo Zhu,Wei Li,Bingyang Lu,Weixing Chen,Wenzhi Zhang,Xiaoling Niu,Xinbing Chen,Zhongwei An
Two series of terminal epoxy compounds, PmOBC (m = 1, 2, 3, 4) and P1OBEn (n = 6, 8, 10, 12), were synthesized for investigating the effect of epoxidation on mesomorphic and thermal stabilities. Molecular polarization and configuration obtained by DFT calculations can provide theoretical perspective. In addition, thermal stability is evaluated by the combination of DSC , TGA , and 1 H NMR. Compared with the corresponding alkenyl compounds, epoxidation reduces the molecular dipole moment and increase the molecular steric effect , which is not conducive to the formation of LC phases, but the reduced intramolecular energy may be helpful to improve thermal stability. Therefore, these terminal epoxy LCs are very promising for application in display devices requiring extremely high-temperature environments.
研究领域:
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
HETEROATOM CHEMISTRY
·
2015
·Vol. 27
·期 1
·63-71
·
IF 1.076
Wang Dai,Qiangqiang Liu,Xiaohui You,Zhongfei Zhou,Yanchun Guo,Yufen Zhao,Shuxia Cao
The Atherton–Todd-type reaction of hydrospirophosphoranes (HSPs) and sodium alcoholates was investigated. Direct alkoxylation of HSPs was accomplished with sodium alcoholates in acetonitrile under nitrogen atmosphere. The stereochemistry mechanism of the alkoxidation of HSPs was proposed by the 31 P NMR tracing experiment. The reaction proceeded via the chlorinated spirophosphorane intermediate with stereoretention of the configuration at phosphorus, followed by the rear and front attack of alkoxide anions to produce alkoxy spirophosphoranes. The reaction mechanism well explained the results of the reaction of HSPs with sodium alcoholates.
研究领域:
有机化学
·
合成化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Dongfang Zhao,Shoulong Dong,Liju Bai,Dongyang Li,Helei Liu
The concentration profiles of all chemicals obtained in the Amine-CO 2 -H 2 O system based on the Vapor-liquid equilibrium (VLE) plots are essential for the analysis and understanding of the kinetics. This work aims at obtaining accurate and reliable VLE plots of 3DMA1P via both experimental and mathematical methods. VLE plots are essential for understanding the reaction process and mechanism of carbon dioxide absorption into amine solutions. The experiments were conducted over a concentration range of 1 ∼ 2 mol/L, temperature of 298 K, and CO 2 partial pressure of 15 kPa. Regarding the experimental method, 13 C NMR detection was performed to generate concentrations of Amine and AmineH + based on the protonation calibration equation. The results showed that the 13 C NMR method had little difference between the results of mass conservation calculation and charge conservation calculation under different CO 2 loading. Among the mathematical methods, the results obtained by the pH method involving charge conservation were quite different from those calculated by mass conservation, while the D-M model method strictly following the theoretical system satisfied both the mass and charge conservation. The distribution curves of the concentration of each species obtained by the three methods were compared. It was found that 13 C NMR and D-M model method could secure closer and more accurate results than the pH method. In conclusion, both the 13 C NMR method and the D-M model method plots are useful for obtaining accurate and reliable VLE plots for the 3DMA1P-CO 2 -H 2 O system, as well as for other monoamine and mixed amine systems.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2024
·
IF 5.6
Weijie Lin,Dengwen Ning,Dezhong Xu,Shuai Wu,Qiuxia Zou,Ajoy Kanti Mondal,Fang Huang
This study compares the behavior of combined and free lignin on the cellulose enzymatic hydrolysis (EH). The combined lignin refers to the lignin naturally existed in the lignocellulose and the free lignin refers to the cellulolytic enzyme lignin. Three kinds of lignocelluloses (i.e., Moso bamboo, horsetail pine and aspen) are chosen for the research. Lignin is mainly biosynthesized of guaiacyl (G), syringyl (S), and p -hydroxyphenyl (H) structural units. The HSQC NMR analysis shows that the free lignin of Moso bamboo, horsetail pine and aspen are mainly composed of G-S-H, G-H and G-S type lignin units, respectively. Furthermore, a blood glucose meter (BGM), UV and fluorescence spectrophotometer are used to determine the cellulose conversion, enzyme adsorption and fluorescence intensities in the EH. It shows that the combined lignin has a weaker inhibitory effect on the EH breakdown than the free lignin. The influence of EH follows the order of Moso bamboo > aspen > horsetail pine. This study can be applied to the development of theoretical guidelines for mitigating the residual prohibition of lignin in the lignocellulose EH.
研究领域:
生物化学
·
植物学
✓ 已验证
产品关联
DOI
高影响因子
FOOD HYDROCOLLOIDS
·
2021
·
IF 9.147
Wei Tang,Dan Liu,Yu Li,Ming-Yue Zou,Yu-Chen Shao,Jun-Yi Yin,Shao-Ping Nie
The water-extracted polysaccharide from Portulaca oleracea L. mainly consisted of two pectic polysaccharides designated as POWP-H and POWP-L. The POWP-L was rich in linear homogalacturonan with GalA content of 77.6%, while POWP-H might be a rhamnogalacturonan I (RG-I) pectin composed of Rha (15.7%), Ara (31.7%), Gal (42.5%) and GalA (10.1%). The structure of POWP-H was elucidated by partial degradation, methylation analysis combined with GC-MS method and NMR spectroscopy. It had a weight-average molecular weight of 1.2 × 10 6 g/mol and high degree of branch of 0.57. The presence of abundant arabinogalactan-II and certain galactan side chains in POWP-H was verified by the T-Ara f (17.4%), 1,3,6-Gal p (11.8%), 1,3-Gal p (8.1%), T-Gal p (13.4%) and 1,4-Gal p (14.3%). The evidence for the RG-I backbone of POWP-H was demonstrated by the structure analysis of its degraded product POWP-H-H, which had the backbone of →4)-α-Gal p A-(1 → 2)-α-Rha p -(1 → 4)-α-Gal p A-(1 → 2,4)-α-Rha p -(1→ substituted by short side chain of β-Gal p -(1 → 4)-β-Gal p -(1→ at O -4 position of →2,4)-α-Rha p -(1 → . Moreover, the POWP-H-H was mainly O -acetylated at O -3 position of α-Rha p with 24.8% acetylation degree. In conclusion, POWP-H was mainly the highly branched and acetylated RG-I pectin with relative short RG-I backbone and abundant arabinogalactan II and certain galactan side chains. Besides, it adopted a flexible chain conformation in 0.1 M NaNO 3 solution.
研究领域:
植物化学
·
食品科学
·
分子生物学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2017
·
IF 6.035
Li Peng,Xiaohan Xu,Xun Yao,Hua Liu,Xuehong Gu
A series of novel hierarchical ZSM-5 zeolite membranes with tunable mesopore sizes have been prepared successfully by using amphiphilic organosilane 3-[(trimethoxysilyl) propyl]octyldimethyl-ammonium chloride (TPOAC) as the mesogenous template and part of the Si source. The effects of several synthesis parameters, such as the TPOAC/SiO 2 ratio, synthesis temperature and crystallization time, on the microstructures and rejection performance of the hierarchical ZSM-5 zeolite membranes were systematically investigated. Multiple techniques, such as XRD , SEM, N 2 adsorption techniques, TEM, IR, 13 C MAS NMR and 29 Si MAS NMR were employed for the characterizations. The filtration of dextran in water shows that the membranes have molecular weight cutoff (MWCO) ranging from 9500 to 943,000, corresponding to the molecular size in the range of 4.5–37 nm. The sharp increase in the rejection of dextran with the increase of molecular weight indicated narrow pore size distribution of the membrane. These results show that the hierarchical mesoporous ZSM-5 zeolite membranes have a great potential for ultrafiltration with high performance.
研究领域:
材料科学
·
化学工程
·
膜技术
✓ 已验证
产品关联
DOI
高影响因子
Magnetic Resonance Letters
·
2023
·
IF 0
Suyu Gu,Guozhong Lu,Nianrui Guo,Juncheng Xu,Yu Jiang,Ming Shen,Bingwen Hu
LiCoO 2 is an important category of active cathode materials in lithium-ion batteries due to its high compacted electrode density, good thermal stability , and stable voltage platform. Recent works on LiCoO 2 have focused on the realization of higher charging voltages to fully utilize its high theoretical capacity. However, an unambiguous atomic-level local probe is essential for the understanding of structure-function correlation. Here we employ high-resolution solid-state nuclear magnetic resonance (NMR) spectroscopy to study the local atomic environments in LiCoO 2 synthesized with three common sintering methods. While one-dimensional 7 Li NMR shows distinct linewidth and subtle dependence on lithium over-stoichiometry, both 7 Li and 59 Co relaxation times are highly dependent on the sintering method. We prove that the two-step sintering method favors the elimination of unreacted Co 3 O 4 , thereby enabling the best discharge capacity in all-solid-state lithium batteries assembled with LiCoO 2 /LGPS/LiIn, which is in accordance with its narrowest 7 Li linewidth and the longest 7 Li/ 59 Co T 1 .
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
DOI
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2022
·Vol. 24
·期 28
·16973-16978
·
IF 3.945
Fengyi Zhou,Ruifen Shi,Yingxiong Wang,Zhimin Xue,Baolong Zhang,Tiancheng Mu
Acidic deep eutectic solvents (ADESs) have been utilized in various applications. Clearly, it is crucial to obtain acidity information that could reveal the relationship with performance. However, appropriate methods for measuring acidity are limited. Herein, we developed two promising approaches (without additional solvents) to identify and characterize both Lewis and Brønsted acidities by applying acetonitrile as an infrared probe and trimethylphosphine oxide (TMPO) as a nuclear magnetic resonance (NMR) probe. The acetonitrile IR approach is suitable for measuring the acidity of Lewis ADESs by monitoring the peak of ν(CN) around 2300 cm−1, and the 31P-TMPO NMR approach could identify and scale both Lewis and Brønsted acidities precisely. Moreover, a perfect linear relationship between the IR shift of ν(CN) and the effective charge density of metal cations was established, which provides a better understanding of Lewis acidity. In short, this study not only offers two efficient acidity measurement methods but also provides a molecular basis for optimizing the performance of ADESs in applications.
研究领域:
化学
·
材料科学
✓ 已验证
DOI
高影响因子
iScience
·
2021
·
IF 5.458
Qingbin Zeng,Qianni Guo,Yaping Yuan,Baolong Wang,Meiju Sui,Xin Lou,Louis-S. Bouchard,Xin Zhou
Magnetic resonance imaging (MRI) provides structural and functional information, but it did not probe chemistry. Chemical information could help improve specificity of detection. Herein, we introduce a general method based on a modular design to construct a molecular building block Xe probe to help image intracellular biothiols (glutathione (GSH), cysteine (Cys) and homocysteine (Hcy)), the abnormal content of which is related to various diseases. This molecular building block possesses a high signal-to-noise ratio and no background signal effects. Its detection threshold was 100 pM, which enabled detection of intracellular biothiols in live cells. The construction strategy can be easily extended to the detection of any other biomolecule or biomarker. This modular design strategy promotes efficiency of development of low-cost multifunctional probes that can be combined with other readout parameters, such as optical readouts, to complement 129 Xe MRI to usher in new capabilities for molecular imaging.
研究领域:
生物化学
·
医学影像
·
分子生物学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Ocean University of China
·
2025
·Vol. 24
·期 6
·1827-1833
·
IF 1.2
Xin Wenyuan,Zhou Yunbing,Liu Daixi,Wang Cong,Sherwin K. B. Sy
Astaxanthin (AX) and vitamin E (VE) are widely consumed nutritional supplements in China, with its beneficial effects predominantly attributed to all-trans AX and VE. The aim of this study is to develop and validate a rapid and accurate method for quantifying the content of AX and VE in nutritional supplement products using highly sensitive 1 H NMR method. Coumarin was chosen as the internal standard. Specific signals from AX was optimal at H-7,7′ in the chemical shift range of δ 6.17–6.24 ppm, whereas the signals of VE at δ 2.59 ppm. To demonstrate the reliability of this analytical approach the proposed method underwent rigorous validation, specificity, limit of detection (LOD), limit of quantitation (LOQ), linearity, accuracy, precision, and recovery. The accuracy of the validation method was 3.10% for AX and 1.99% for VE. The results indicated that the method was precise and reliable. The method has been successfully applied to simultaneous quantification of AX and VE in nutritional supplements products.
研究领域:
分析化学
·
营养科学
·
药物分析
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 1
·251
·
IF 4.2
Qiulin Li,Yawen Yang,Qingfeng Wang,Xiang Han,Junfeng Zhu,Nan Zhang,Qiuhong Wang,Kanshe Li,Pin Gong,Fuxin Chen
This article applies nuclear magnetic resonance technology to the study of boron-containing traditional Chinese medicine, in order to explore the morphological evolution of boron elements in traditional Chinese medicine. Borax is a traditional Chinese medicine with anti-corrosion, anti-inflammatory, antibacterial, and anticonvulsant effects. It is made by boiling, removing stones, and drying borax minerals like borate salts. This article introduces an11B nuclear magnetic resonance method for identifying and characterizing boron-containing compounds in TCM. We applied this technology to borax aqueous solutions in different chemical environments and found that with boron mixed in the form of SP2hybridization in equilateral triangles and SP3hybridization in equilateral tetrahedra, the pH changes in alkaline environments significantly affected the ratio of the two. At the same time, it was found that in addition to the raw material peak, boron signals of other boron-containing compounds were also detected in 20 commercially available boron-containing TCM preparations. These new boron-containing compounds may be true pharmaceutical active ingredients, and adding them directly to the formula can improve quality and safety. This article describes the detection of11B NMR in boron-containing traditional Chinese medicine preparations. It is simple, non-destructive, and can provide chemical fingerprint studies for boron-containing traditional Chinese medicine.
研究领域:
药学
·
化学
✓ 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）