ANALYST
·
2023
·
IF 4.2
Lihua Xu,Qiong Wang,Yan Liu,Songsen Fu,Yufen Zhao,Shaohua Huang,Biling Huang
Chiral amino-group compounds are of significance for human health, such as biogenic amino acids (AAs), dipeptides, and even various drugs. Enantiospecific discrimination of these chiral compounds is vital in diagnosing diseases, identifying pathological biomarkers and enhancing pharmaceutical chemistry research. Here, we report a simple and rapid 19F NMR-based strategy to differentiate chiral AAs, dipeptides, and amines, that were derivatized with (R)-2-(2-fluorophenyl)-2-hydroxyacetic acid ((R)-2FHA). As a result, 19 proteinogenic AAs (37 isomers) as well as Gly could be concurrently resolved. Moreover, various mirror-image dipeptides, such as Ser–His, Leu–Leu, and Ala–Ala, were commendably recognized. Intriguingly, we found that the absolute configuration of AAs in the N-terminus of dipeptides decided the relative 19F chemical shifts between two enantiomers. Besides, the ability of this method for enantiodiscrimination was further demonstrated by non-AA amines, including aromatic and aliphatic amines, and even amines having chiral centers several carbons away from the amino-group. The structurally similar antibiotics, amoxicillin and ampicillin, were well discriminated. Furthermore, this method accurately determines the de or dr values of non-racemic mixtures. Therefore, our strategy provides an effective approach for 19F NMR-based enantiodiscrimination and diastereomeric purity determination of amino-group compounds.
研究领域:
分析化学
·
药物化学
·
生物化学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2025
·
IF 6.7
Shuyi Lu,Qian Wu,Shanshan Wang,Dongru Sun,Yan Liu,Shaohua Huang,Biling Huang
19F-labeled molecular probes offer significant advantages in chiral analysis, with their stereostructures playing a critical role in enantiodiscrimination. Rapid and accurate assignment of absolute configurations is particularly important for the pharmaceutical field and asymmetric synthesis. This work presents a comparative evaluation of two 19F-labeled probes as CDAs: aromatic P1 ((S)-1-(2-fluorophenyl)ethylamine) and aliphatic P2 (trans-2-fluorocyclohexanamine), focusing on their enantiomeric recognition of chiral carboxylic acids. The results demonstrate that P1 outperformed P2, particularly in analyzing carboxylic acids with chiral centers positioned several carbons away from the carboxyl group or possessing multiple chiral centers. Density functional theory calculations elucidated the underlying mechanisms, revealing that P1’s great recognition efficiency arises from a larger energy difference between diastereomers and the formation of hydrogen bonds between its fluorine atom and the analytes’ protons. These findings emphasize the importance of probe–analyte interactions in CDA-based enantiorecognition systems for achieving high-resolution discrimination. Moreover, P1 exhibited practical applications in determining ee values and analyzing various brands of ibuprofen capsules and tablets, highlighting its potential for pharmaceutical quality control. Furthermore, we introduced a novel online platform combining a P1-guided 19F NMR approach with machine learning for automated prediction of absolute configurations. This work sheds light on the differences between aromatic and aliphatic probes in enantiorecognition, while introducing an online predictive tool, in favor of the design of 19F molecular probes and the rapid assignment of absolute configurations.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MACROMOLECULES
·
2025
·
IF 5.2
Minzhi Duan,Ming Wu,Qi Jin,Yuling Liang,Jiawen Hou,Rongchun Zhang,Pingchuan Sun,Xiaoliang Wang
Unconventional polymer networks (UPNs) have unique mechanical properties due to their special network structures, e.g., the rotaxane dissipates external energy during stretching through the sliding of the rings. In this work, we made a rubbery poly(thioctic acid) (PTA) network by a facile method cross-linked by rotaxanes, which were obtained by self-assembly of α-cyclodextrins (α-CDs) with poly(ethylene glycol) diacrylate (PEGDA). By master-curve from time–temperature superposition experiments and transient stress relaxation experiments, the consistent rheological behavior of slide-ring energy dissipation was found. The results of low-field solid-state nuclear magnetic resonance with an in situ stretching fixture suggested that 16.56% of the α-CDs could slide along the PEGDA chains during stretching, transforming from the rigid fraction to the relatively mobile fraction. The α-CDs threaded on PEGDA were verified by 1H–1H and 1H–13C high-field solid-state nuclear magnetic resonance experiments. Furthermore, the changes in the local dynamics due to the dipolar interaction of the α-CDs with PEGDA were identified by 2D proton wide-line separation experiments. This work provided a facile way to synthesize rotaxane-based elastomers, and the energy dissipation mechanism therein was clearly demonstrated, which may pave a new way to design UPNs with better energy dissipation.
研究领域:
高分子科学
·
材料科学
·
物理化学
·
机械工程
·
核磁共振光谱学
✓ 已验证
产品关联
DOI
高影响因子
CEMENT AND CONCRETE RESEARCH
·
2025
·
IF 13.1
Jing Qiao,Chunsheng Zhou,Jingjing Feng,Miao Miao,Yanliang Ji,Linan Gu
Limestone powder (LS) with large particle sizes is widely used, but its effect on water migration behavior remains unclear. This study investigates the influence of LS and viscosity-enhancing admixtures (VEAs) on the water migration behavior and water distribution in fresh cement paste using 1 H low-field nuclear magnetic resonance (LF-NMR). Results indicate that LS increases the size of water migration channels, accelerates the water migration rate, and raises the bleeding ratio, while VEAs substantially mitigate the effects of LS. Compared to polyacrylamide, cellulose ether significantly slows down the water migration rate before 40 min, thereby reducing the bleeding ratio. Additionally, relaxation times were found to decrease during bleeding and can reflect the sedimentation process. It is confirmed that the pore structure of fresh paste exhibits fractal characteristics, with the fractal dimension closely correlating with water migration rates. The underlying mechanisms and their implications on material behavior are thoroughly analyzed and discussed.
研究领域:
材料科学
·
土木工程
✓ 已验证
DOI
高影响因子
JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
·
2013
·
IF 2.947
Baogang Xie,Aihong Liu,Xiuzhong Fang,Ying Chen,Haijun Zhong
Determination of alendronate is crucial to routine quality control of alendronate tablets. However, tedious sample treatment processes such as derivatization were generally required by chromatographic separation of alendronate as its high polarity and no chromophore in the molecular structure. Here, we describe the use of 1 H NMR for the quantification of alendronate sodium in tablets. Linearity, recovery, selectivity and sensitivity of the assay were validated to be satisfactory with quick sample preparation and acquisition. The contents of alendronate sodium in tablets from five manufacturers were determined, the results showed that all assayed tablets fell within the range of 90.0–110.0% of the label claim and the relative standard deviation was less than 6.0%. The method was also successfully employed for alendronate tablet dissolution assay in this study.
研究领域:
药学
·
分析化学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2023
·Vol. 42
·期 1
·113-124
·
IF 4.3
Lv Jing,Chen Xu,Wu Zi-Shuo,Li Ya-Hui,Chen Wei
The chain dynamics heterogeneity of the poly(vinyl butyral) (PVB) plasticized by triethylene glycol bis(2-ethylhexanoate) (TEG-EH) was investigated by various solid-state NMR techniques. The plasticized PVB shows two domains in distinct molecular dynamics differences, namely, rigid and soft domains, where the latter is the plasticizer-rich domain. The time domain low field NMR was first used to investigate the dynamics heterogeneity of the plasticized PVB, and the results show the decreasing activated energy of components in the soft domain of plasticized PVB ( E a =20.2 kJ/mol) as compared with that of the pristine one ( E a =24.3 kJ/mol). Detailed dynamics heterogeneity was obtained by high-field NMR with site-specific features. The quadrupole-echo 2 H-NMR was adopted to elucidate the dynamics heterogeneity of the vinyl alcohol (VA) units, where only the hydroxyl group of VA is deuterated. The 1 H- 13 C WISE NMR spectra show that there is not much difference in the mobility of the VB unit in PVB with and without plasticizer, whereas the glass transition temperature differed by approximately 53 °C. This is further supported by Torchia’s T 1 relaxation measurements. The origin of such an unusual phenomenon is attributed to the critical role of the remaining VA (∼22%) in the soft domain, where the VA units locally aggregate through hydrogen bonding. Also, the existence of a mobility gradient in the VB unit has been demonstrated. Moreover, the mobility difference for VB with different stereo-geometry ( meso or racemic conformation) is observed for the first time. This indicates the importance of modulating the ratio of meso over racemic VB for controlling the macroscopic performance of PVB.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
·
2016
·
IF 4.509
Dehua Wang,Shutao Xu,Miao Yang,Yueying Chu,Peng Tian,Zhongmin Liu
A pure fluorinated aluminophosphate [Al8P8O32F4·(C3H12N2)2(H2O)2] (ULM-6) has been synthesized via an aminothermal strategy, in which triisopropanolamine (TIPA) is used as the solvent together with the addition of propyleneurea and HF. The 13C NMR spectrum demonstrates that 1,3-diaminopropane, the in situ decomposer of propyleneurea, is the real structure-directing agent (SDA) for ULM-6 crystals. The local Al, P, and F environments of the dehydrated ULM-6 are investigated by 1D and 2D solid-state NMR spectroscopy. The spatial proximities are extracted from 19F{27Al}, 19F{31P}, 27Al{19F}, and 31P{19F} rotational-echo double resonance (REDOR) NMR experiments as well as 19F → 31P heteronuclear correlation (HETCOR) NMR and {31P}27Al HMQC NMR experiments, allowing a full assignment of all the 19F, 27Al, and 31P resonances to the corresponding crystallographic sites. Moreover, it is found that the structure of ULM-6 is closely related to that of AlPO4-14. A combination of high-temperature powder XRD, thermal analysis, and 19F NMR reveals that the removal of fluorine atoms at higher temperature is crucial to the phase transformation of ULM-6 to AlPO4-14. The calcined product shows high CO2/CH4 and CO2/N2 selectivity with ratios of 15.5 and 29.1 (101 kPa, 25 °C), respectively.
研究领域:
材料科学
·
无机化学
·
固体核磁共振波谱学
·
微孔材料
·
分子筛
✓ 已验证
DOI
高影响因子
Green Energy & Environment
·
2017
·
IF 0
Fen Yue,Christian Marcus Pedersen,Xiuyin Yan,Yequn Liu,Danlei Xiang,Caifang Ning,Yingxiong Wang,Yan Qiao
Hydrothermal carbonization (HTC) is a valuable approach to convert furfural residue (FR) into carbon material. The prepared biochars are usually characterized comprehensively, while the stock process water still remains to be studied in detail. Herein, a NMR study of the main components in stock process water generated at different HTC reaction conditions was reported. Various qualitative and quantitative NMR techniques ( 1 H and 13 C NMR, 1 H– 1 H COSY and 1 H 13 C HSQC etc. ) especially 1D selective gradient total correlation spectroscopy (TOCSY NMR) were strategically applied in the analysis of HTC stock process water. Without separation and purification, it was demonstrated that the main detectable compounds are 5-hydroxymethylfurfural, formic acid, methanol, acetic acid, levulinic acid, glycerol, hydroxyacetone and acetaldehyde in this complicate mixture. Furthermore, the relationship between the concentration of major products and the reaction conditions (180–240 °C at 8 h, and 1–24 h at 240 °C) was established. Finally, reasonable reaction pathways for hydrothermal conversion of FR were proposed based on this result and our previously obtained characteristics of biochars. The routine and challenging NMR methods utilized here would be an alternative other than HPLC or GC for biomass conversion research and can be extended to more studies.
研究领域:
化学工程
·
生物质能研究
✓ 已验证
产品关联
DOI
FUEL PROCESSING TECHNOLOGY
·
2018
·
IF 3.956
Hui Ma,Yan Qiao,Christian Marcus Pedersen,Pengfei Wang,Mengjie Wu,Pengfei Liu,Xianglin Hou,Tuoping Hu,Yingxiong Wang
Fischer–Tropsch wastewater (FTW), co-produced with hydrocarbons in Fischer–Tropsch process, is usually rich in water-soluble oxygenates, e.g. carboxylic acids, alcohols and aldehydes. Purification of FTW is crucial for achieving effective resource utilization and environmental concerns. The adsorption of FTW by humic acid (HA) has been studied via NMR. Butanol isomers, n-butanol (n-BuOH), sec-butanol (s-BuOH), iso-butanol (i-BuOH) and tert-butanol (t-BuOH), were used as model compounds of water soluble organic constituent for FTW. The interaction between HA and BuOHs was evaluated based on the NMR study. Lack of chemical shift change and broadening of peak width were observed with successive HA addition, 1 H spin-lattice and spin-spin relaxation time of BuOHs decrease and 1 H correction time increased. Association percentage to HA, association constants and Gibbs free energies for BuOHs were calculated. The adsorption efficiency of BuOHs decreased in the order: s-BuOH > n-BuOH > i-BuOH > t-BuOH. The effects of HA concentration and solution pH value on the interaction were examined, and the interaction is favored by increasing HA concentration, but less dependent on solution pH value. The studied process is effective for treating FTW and has a great potential for industrial applications due to its simplicity and low price.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOLUTION CHEMISTRY
·
2016
·Vol. 45
·期 3
·359-370
·
IF 1.256
Zhu Xiao,Zhang Huan,Xu Yingjie
In order to uncover the micro-structural heterogeneities in solutions of ammonium based ionic liquids, triethylamine nitrate (N 222 NO 3 ) has been synthesized using acid–base neutralization and the 1 H NMR spectra of two binary mixtures, namely N 222 NO 3 /dimethyl sulfoxide (DMSO) and N 222 NO 3 /acetone at different concentrations, have been measured at 298.15 K. The internal reference method was adopted to obtain the concentration-dependent chemical shifts of –CH 3 in N 222 NO 3 , which have been correlated using the 1 H NMR local composition (LC) model to obtain the local mole fractions. It has been revealed that within N 222 NO 3 rich region, self-association of the ionic liquid was predominant instead of N 222 NO 3 –solvent interactions. However, in the solvent rich region, N 222 NO 3 mainly interacts with solvent molecules, indicating that the self-association network of N 222 NO 3 has been greatly destroyed by solvents. In addition, the different influences of DMSO and acetone have been detected. DMSO molecules more effectively destroy the original network of the ionic liquid, due to its higher dielectric constant. Also, LC behavior in N 222 NO 3 /DMSO systems is more significant than in N 222 NO 3 /acetone, indicating that DMSO can induce more obvious heterogeneities in DMSO/N 222 NO 3 mixtures, which is consistent with physicochemical properties and cellulose solubility of solutions.
研究领域:
化学
·
物理化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MAGNETIC RESONANCE IN CHEMISTRY
·
2017
·Vol. 56
·期 1
·37-45
·
IF 1.601
Chen Yu,Qian Zhang,Peng-yao Xu,Yin Bai,Wen-bin Shen,Bin Di,Meng-xiang Su
Quantitative nuclear magnetic resonance (qNMR) is a well-established technique in quantitative analysis. We presented a validated 1 H-qNMR method for assay of octreotide acetate, a kind of cyclic octopeptide. Deuterium oxide was used to remove the undesired exchangeable peaks, which was referred to as proton exchange, in order to make the quantitative signals isolated in the crowded spectrum of the peptide and ensure precise quantitative analysis. Gemcitabine hydrochloride was chosen as the suitable internal standard. Experimental conditions, including relaxation delay time, the numbers of scans, and pulse angle, were optimized first. Then method validation was carried out in terms of selectivity, stability, linearity, precision, and robustness. The assay result was compared with that by means of high performance liquid chromatography, which is provided by Chinese Pharmacopoeia. The statistical F test, Student's t test, and nonparametric test at 95% confidence level indicate that there was no significant difference between these two methods. qNMR is a simple and accurate quantitative tool with no need for specific corresponding reference standards. It has the potential of the quantitative analysis of other peptide drugs and standardization of the corresponding reference standards.
研究领域:
药物分析
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL RESEARCH IN TOXICOLOGY
·
2022
·
IF 3.973
Liming Wang,Shuo Huang,Tongtong Zhu,Xiaoyan Ge,Chenxi Pei,Ge Hong,Lifeng Han
Iohexol, the raw material of nonionic X-ray computed tomography (X-CT) contrast medium, is usually injected into the vein before CT angiography diagnosis. It is used for angiography, urography, and lymphography. With the advantages of low contrast density and good tolerance, it is currently one of the most popular contrast media. However, the renal toxicity of iohexol seriously affects its safety use. Therefore, it is of great importance to identify new potential diagnostic biomarkers and therapeutic targets in the process of contrast medium-induced acute kidney injury (CI-AKI) in order to safely use iohexol in clinical practice. In this study, in order to understand the metabolic mechanism of CI-AKI, ultra-high-performance liquid chromatography/quadrupole-Orbitrap-mass spectrometry and 1H NMR-based metabolomic techniques were utilized to study the metabolic spectra of kidney, plasma, and urine from CI-AKI rats, and a total of 30 metabolites that were closely related to kidney injury were screened out, which were mainly related to 9 metabolic pathways. The results further indicated that iohexol might intensify kidney dysfunction in vivo by disrupting the metabolic pathways in the body, especially through blocking energy metabolism, amino acid metabolism, and promoting inflammatory reactions.
研究领域:
药理学
·
毒理学
·
代谢组学
·
临床医学
✓ 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）