Journal of the American Chemical Society
·
2026
·
IF 16.6
Xiaoli Xia,Fang Wang,Changju Yang,Yujie Wen,Xiang Ning,Zhengting Zhang,Juan Wen,Zhonghan Feng,Xiaokang Ke,Zhiwu Yu,Hanxi Guan,Wenhua Hou,Xuefeng Guo,Weiping Ding,Di Wu,Yadong Li,Luming Peng
Light-element isolated species represent an emerging class of atomically dispersed nanomaterials, yet their precise local and higher-shell coordination environments remain largely inaccessible due to the intrinsic limitations of conventional nanoscale probes. Here, we establish a solid-state NMR method, combining 23Na and 17O spectroscopy with first-principles calculations, to directly resolve the atomic-scale structure of light-element isolated species beyond the first coordination shell. Using Na-modified CeO2 as a representative system, isolated and aggregated sodium species are distinguished by characteristic 23Na NMR signatures, while 17O NMR further reveals how light element dopants perturb oxygen coordination across the first to third atomic shells. This approach enables clear differentiation of Na–O–Ce linkages from more remote Na–O–Ce–O environments that are inaccessible to electron microscopy and X-ray-based techniques. As a demonstration of atomic-scale structure-adsorption correlation, CO2 is shown to preferentially adsorb at Na–O–Ce sites rather than at Na–O–H groups.
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npj Materials Degradation
·
2026
·
IF 7.5
Khan Muhammad Amer,Hu Lili,Chen Shubin,Xu Yongchun,Ren Jinjun
Corrosion mechanism of minerals and glass is a critical study domain in geology and materials science, vital for comprehending material durability under various environmental conditions. Despite decades of extensive study, a core aspect of these mechanisms—specifically, the formation of amorphous alteration layers upon exposure to aqueous environments—remains controversial. In this study, the corrosion behavior of a boro-alumino-phospho-silicate glass (BAPS) was investigated using advanced solid-state nuclear magnetic resonance (SSNMR) and SEM techniques. The results are consistent with a uniform nanoscale phase separation into aluminum phosphrous -rich and aluminum silicate-rich domains. During corrosion, the aluminum phosphrous -rich domains undergo gelation, whereas the aluminum silciate-rich domains remain vitreous, forming a gel layer comprised of both phases. Although SEM images show a sharp gel/glass interface—suggestive of a dissolution-precipitation mechanism, multiple lines of evidence indicate that an in situ transformation mechanism is more consistent with our findings, even if dissolution–precipitation cannot be entirely excluded. This in situ transformation is governed by a series of coupled chemical reactions, involving: (i) preferential hydrolysis of aluminum phosphrous -rich domains leading to porous gel regions; (ii) retention of aluminum silciate-rich glass domains within the gel layer, with water infiltrating inter-network spaces; and (iii) selective leaching of phosphorus over aluminum, leading to reorganization of the gel network. The alternative text for this image may have been generated using AI.
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ENERGY & FUELS
·
2026
·Vol. 40
·期 33
·18014-18027
·
IF 6
Wang Chong,Xia Runtian,Cai Xinheng,Zhang Zhihua,Wang Wei,Zhang Qundan
To
support the optimization and screening of catalysts for the
residue hydrodesulfurization (HDS) process, it is essential to conduct
in-depth characterization of sulfur-containing compounds (SCCs) in
the residue. In this study, a combination of 13 C-methylation
derivatization and 13 C nuclear magnetic resonance (NMR)
spectroscopy was employed to investigate the structural details of
sulfur-containing compounds in residual oil on the basis of diverse
model compounds. The results showed that the chemical shift of the 13 C-methyl group attached to the sulfur atom in the internal-type
thiophenic aromatic compounds (such as dibenzothiophene) is greater
than 35 ppm, while the chemical shift of the 13 C-methyl
group attached to the sulfur atom in the thiophenes, terminal-type
thiophenic aromatic compounds (such as naphthothiophene), and those
with alkyl substituents is 29–35 ppm. When the 13 C-methyl is substituted on the carbon atom in the terminal thiophene
ring, its chemical shift is within the range of 10–15 ppm.
In addition, the chemical shift range of 15–29 ppm is observed
and attributed to the 13 C-methyl and alkyl groups substituted
on the aromatic ring in both the internal-type and terminal-type thiophenic
aromatic compounds. These rules were further applied to the characterization
of the residue oil and its hydrodesulfurization product. The analytical
results indicate that the molecular structure of refractory sulfur
compounds in the deep hydrotreated residue is dominated by the sterically
hindered internal-type thiophenes with long alkyl side chains. The
established method can be used for the characterization of isomers
of sulfur-containing compounds in the residue and other petroleum
products, thereby providing reference information for subsequent hydrodesulfurization
and hydrogenation research.
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BMC Chemistry
·
2025
·Vol. 19
·期 1
·1-10
·
IF 4.6
Niu Jiajia,He Aimin,Gao Feng,Yu Zhenhua,Li Jiehui,Liu Yang,Hao Hongling,Chen Jingzheng,Zhang Fengmei,Chen Chen,Yue Liqing
It is important to accurately test the content of the main components (i.e., oxyacetyl, vinyl, and vinyl alcohol) of VAE-type adhesives/emulsions. In this study, we first investigated the solubility of dried VAE samples. Dimethyl sulfoxide (DMSO) was the best solvent tested, and at a sample concentration of 10,000 µg/mL, complete dissolution was achieved after 3 h of ultrasonication. Second, different chemical shifts of protons in the 1H NMR spectrum of VAE samples were assigned as follows: 2.01 ppm for CH3 of oxyacetyl groups, 1.5–1.8 ppm for the backbone CH2 connected to vinyl alcohol or oxyacetyl groups, and 1.2 ppm for the backbone CH2. Based on these assignments, an 1H NMR normalization-based quantification method was established. Meanwhile, correction factors of each VAE functional group relative to the internal standard benzyl benzoate were calculated to establish an 1H NMR internal standard-based quantification method. For the vinyl acetate monomer that was tested as a proxy for the oxyacetyl group, the 1H NMR internal standard-based quantification method yielded a closer result (37.44%) to the classical method (37.30%) than the normalization-based method. The method exhibited good repeatability and reproducibility (repeatability RSD < 5%, reproducibility RSD: vinyl and oxyacetyl < 5%, vinyl alcohol < 11.24%). In contrast, a 13C NMR internal standard-based quantification method was deemed unsuitable for the quantitative analysis of VAE main components due to its high sample concentration requirements, lengthy test durations, and tendency to underestimate the actual contents. Finally, a 1H NMR internal standard-based quantification method was established for the determination of the main components of VAE-type adhesives/emulsions.
研究领域:
分析化学
·
高分子科学
·
材料工程
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ANALYTICAL CHEMISTRY
·
2025
·
IF 6.7
Huan Yao,Ting Huang,Zhifang Li,Huaxin Wu,Xueyao Li,Hua Tang,Fuhai Su,Xinliang Jin,Wei Zhang
Purity assessment is critical for the quality control of active pharmaceutical ingredients (APIs). However, there is a lack of rapid and accurate purity assessment methods that operate independently of target-specific certified reference materials (CRMs). Herein, we proposed a traceable quantification method, named SFC-ISC-qNMR, for purity assessment and quantitative determination of low-purity APIs, which was accomplished by tracing the test solution to the reference solution via supercritical fluid chromatography (SFC) collection with internal standard-correction (ISC), followed by an SI-traceable quantitative nuclear magnetic resonance (qNMR) analysis of the reference solution (SI = International System of Units). Digitoxin, a widely used cardiac glycoside in the treatment of heart failure and arrhythmias, was used as a model compound. By employing a mobile phase of supercritical CO2 modified with 24%–26% methanol, digitoxin with a purity exceeding 99.87% was isolated and collected. A national CRM of ethyl para-hydroxybenzoate was used as the IS for digitoxin. The SFC-ISC reference solution can be prepared in 15 min without the need for precise weighing, simply by reconstitution of the SFC collected high-purity analyte in deuterated methanol containing IS. The feasibility and reliability of the SFC-ISC-qNMR method were exhibited through the quantitative determination of digitoxin in chemical mixtures. The purity of a commercially available digitoxin reagent was determined to be 94.17% ± 0.15%, which was consistent with high-resolution qNMR analysis. The contents of spiked digitoxin in a digoxin analytical standard were measured at 1.06%, 1.37%, 2.39%, and 4.43%, respectively, showing high consistency with the gravimetric value with a bias less than 0.13%. In contrast, direct qNMR with deconvolution and HPLC analysis failed to provide accurate measurements. These results highlight the applicability of the SFC-ISC-qNMR method for drug evaluation and research, demonstrating its significant potential for the purity assessment of APIs.
研究领域:
分析化学
·
药物分析
·
色谱分析
·
核磁共振（NMR）
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LWT-FOOD SCIENCE AND TECHNOLOGY
·
2024
·
IF 6
Dan Peng,Qi Zhou,Min Su,Shaoshuai Zheng,Shuli Xie,Jun Li
Low-field nuclear magnetic resonance (LF-NMR) combined with chemometrics was used for the rapidly and nondestructively quantitative determination of carbonyl value (CV) of frying oils during frying process. The quality indices of frying oils during frying process were analyzed as well as the changes of its LF-NMR signal, followed by exploring the correlation between the quality indices of frying oils and the relaxation-characteristic indices and investigating the influences of modeling data and preprocessing methods on the modeling performance. Based on the echo decay curves data of LF-NMR and the relaxation-characteristic indices data, the prediction model of CV was established by partial least square (PLS), principal component regression (PCR), multiple linear regression (MLR), and support vector machine regression (SVR). Results showed that there was a significant correlation between CV and relaxation-characteristic indices ( p < 0.01) with both modeling data and preprocessing methods affecting the model performance. The prediction performance of non-linear SVR model was significantly superior to that of linear modeling methods (PLS, PCR, and MLR). The best prediction model of CV was built using the SVR method based on echo decay curves data. The root mean square error of prediction and coefficient of determination were 2.599 mmol/kg and 0.9873, respectively.
研究领域:
食品科学
·
分析化学
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WATER RESEARCH
·
2025
·
IF 12.4
Ping Sun,Xuan-Xin Chen,Yuan-Ping Zeng,Zhi-Yi He,Yun-Yan Gao,Raymond Jianxiong Zeng,Hou-Feng Wang
The distribution and transformation of water content critically influence sludge dewatering performance and remain central to sludge treatment research. Low-field nuclear magnetic resonance (LF-NMR), known for its non-destructive and rapid analysis, has emerged as a vital tool for characterizing water distribution in sludge, though its limitations require further investigation. This study employed LF-NMR to analyze T₂ relaxation spectra of sludge under various pretreatments and with differing water contents (97 %–62 %). Results indicated that, despite similar overall water content, sludge subjected to different pretreatments exhibited significant variations in T₂ peak counts and times. Notably, T₂₁, T₂₂, T₂₃, and T₂₄ showed significant exponential relationships with water content (p < 0.0001). The transformation and migration of adsorbed, interstitial, and free water demonstrated complex bidirectional continuity. Removal of adsorbed and interstitial water significantly altered sludge structure, diminishing the reversibility of water reabsorption, whereas removal of free water had minimal impact on microstructure. Overlapping T₂ relaxation peaks suggested continuous transitions among water states, challenging the traditional discrete categorization. Neglecting changes in T₂ peak times may lead to misinterpretation of water states and affect assessments of dewatering performance. While LF-NMR shows great potential, its limitations in resolving overlapping peaks and quantitatively assessing water states must be acknowledged. Consequently, LF-NMR should be regarded as a qualitative or semi-quantitative method rather than a purely quantitative tool as often assumed. Future research should integrate higher-resolution T₁–T₂ two-dimensional NMR techniques with advanced data processing to more accurately elucidate the mechanisms of water migration and transformation within sludge.
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ACS Catalysis
·
2024
·
IF 11.3
Wei Gao,Guodong Qi,Chao Wang,Qiang Wang,Jiawei Liang,Jun Xu,Feng Deng
The co-aromatization of methane and organic compounds using metal-modified zeolite catalysts represents a promising approach for the direct conversion of natural gas into valuable aromatics. In this work, we employ solid-state nuclear magnetic resonance (NMR) spectroscopy to systematically examine the reaction mechanism and evaluate the impact of co-feeding furan on methane aromatization over Mo/ZSM-5 zeolite. The results reveal a dual role of furan in promoting methane to aromatics and stabilizing the Mo/ZSM-5 zeolite catalyst in the co-aromatization. It is found that co-feeding a moderate amount of furan enhances methane conversion and boosts the selectivity to benzene, toluene, and xylene (BTX). The 12C/13C isotope switching experiments coupled with 1H and 13C MAS NMR spectroscopy reveal that furan actively participates in the methane aromatization reaction by forming an olefin pool, which promotes methane activation and contributes to the following aromatics formation. Two-dimensional 1H–95Mo heteronuclear correlation NMR spectroscopy indicates that furan facilitates the activation of Mo oxides into MoOxCy species, which serve as the active sites for methane aromatization. The co-feeding furan also helps to enhance catalyst stability by limiting the agglomeration of Mo and the deposition of coking species.
研究领域:
催化化学
·
材料科学
·
能源化学
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ANALYTICAL CHEMISTRY
·
2024
·
IF 6.7
Xijian Wu,Xin Tong,Biling Huang,Shaohua Huang
Rapid detection of amines in complex mixtures presents a significant challenge. Here, we introduce a novel nuclear magnetic resonance (NMR) method for amine detection utilizing a probe with two fluorine atoms in distinct chemical environments. Upon interaction with an amine, the probe generates two atomic resonance peaks, which are used to create coordinates, revealing fluorine chemical shifts on the 19F NMR spectroscopy. This innovative approach allows for the clear distinction of amine signals in a two-dimensional plane. This method has been effectively employed in analyzing amines in pharmaceuticals and amino acids in Ophiopogon japonicus and dry white wine, providing a robust and general approach for amine analysis.
研究领域:
分析化学
·
药物分析
·
核磁共振波谱学
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JOURNAL OF MOLECULAR STRUCTURE
·
2025
·
IF 4.7
Wanting Guo,Christian Marcus Pedersen,Zhihui Liu,Wenbo Dong,Lingyu Jia,Shuwei Chen,Yingxiong Wang,Yan Qiao
Carbazole (CAR) and anthracene (AN) are high value compounds derived from coal tar, but their separation is challenging due to their structural similarity. Promising results, using deep eutectic solvents (DESs) for the separation, have recently been obtained. However, choosing the optimal DESs for the separation of CAR and AN is difficult due to a lack of knowledge about the interaction of DESs with CAR and AN. Herein, the interactions between CAR and AN with seven DESs containing ethylene glycol (EG) as the hydrogen bond donor (HBD) were investigated by nuclear magnetic resonance (NMR). The interaction between CAR and tetrabutylammonium chloride/ ethylene glycol (TBAC/EG) was investigated using various NMR methods such as chemical shift titration, variable temperature NMR (VT-NMR), relaxation time measurements and diffusion-ordered spectroscopy (DOSY). From the chemical shift differences of the N H proton of CAR, a strong interaction between CAR and the DES consisting of TBAC and EG, was revealed. TBAC/EG was therefore proposed as a promising solvent for the separation of CAR and AN. In addition, VT-NMR showed that the hydrogen bonding interaction between CAR and TBAC/EG increased with decreasing temperature. The changes in relaxation time (T 1 , T 2 ), molecular correlation time (τ c ) and the molecular self-diffusion coefficients (D) supported the existence of interactions between CAR and TBAC/EG, presumably dominated by hydrogen bonding between the N H and the chloride ion. This study introduces an efficient method for screening solvents to separating CAR and AN, and it can also be applied to other fields of separating complex mixtures.
研究领域:
化学
·
分离科学
·
材料科学
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MOLECULES
·
2021
·Vol. 26
·期 9
·2793
·
IF 4.412
Tao Chen,Xin Hu,Zhong Chen,Xiaohong Cui
The synergism/inhibition level, solubilization sites and the total solubility (St) of co-solubilization systems of phenanthrene, anthracene and pyrene in Tween 80 and sodium dodecyl sulfate (SDS) are studied by1H-NMR, 2D nuclear overhauser effect spectroscopy (NOESY) and rotating frame overhauser effect spectroscopy (ROESY). In Tween 80, inhibition for phenanthrene, anthracene and pyrene is observed in most binary and ternary systems. However, in SDS, synergism is predominant. After analysis, we find that the different synergism or inhibition situation between Tween 80 and SDS is related to the different types of surfactants used and the resulting different co-solubilization mechanisms. In addition, we also find that three polycyclic aromatic hydrocarbons (PAHs) have similar solubilization sites in both Tween 80 and SDS, which are almost unchanged in co-solubilization systems. Due to the similar solubilization sites, the chemical shift changes of surfactant and PAH protons follow the same pattern in all solubilization systems, and the order of chemical shift changes is consistent with the order of changes in the St of PAHs. In this case, it is feasible to evaluate Stof PAHs by chemical shift. In both Tween 80 and SDS solutions, the ternary solubilization system has relatively high Strankings. Therefore, in practical applications, a good overall solubilization effect can be expected.Keywords:polycyclic aromatic hydrocarbon;co-solubilization;surfactant;NMR;total solubility
研究领域:
环境科学
·
化学
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JOURNAL OF NANOPARTICLE RESEARCH
·
2020
·Vol. 22
·期 11
·1-9
·
IF 2.132
Gao Wenshan,Zhang Yuangong,Zheng Ying,Zhang Hailei,Wang Xiaoke,Bai Libin,Wu Yonggang,Ba Xinwu
The 19 F nuclear magnetic resonance (NMR) has been widely employed as a detection tool in biological studies due to its low biological background, noninvasiveness, high sensitivity, and real-time monitoring capability. Herein, we report a one-pot synthesis of halloysite nanotubes (HNTs) treated with benzeneboronic acids (6FBB) to afford the HNT-based 19 F NMR probe which is capable to detect the H 2 O 2 in low concentration. The product was well characterized by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The intensity of signals of 19 F was enhanced with the increasing concentration of fluorine, and the signals apparently shifted from − 62.68 to − 62.85 ppm upon the addition of H 2 O 2 . The obtained 19 F NMR probes also displayed a long spin-spin (T2) relaxation time (91.27 ms), which can strengthen image intensity. Moreover, the 19 F NMR probe exhibited non-toxic against HeLa cell. The 19 F NMR probe may serve as a desirable candidate to predict the change of H 2 O 2 in vivo.
研究领域:
生物化学
·
医学影像学
·
材料科学
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危险品化学品经营许可证（带存储）