ANALYTICA CHIMICA ACTA
·
2019
·
IF 5.256
Hui Ma,Christian Marcus Pedersen,Qi Zhao,Zexiang Lyu,Hui Chang,Yan Qiao,Xianglin Hou,Yingxiong Wang
The Fischer–Tropsch (FT) process is a practical approach to convert synthesis gas (CO and H 2 ) into hydrocarbons and oxygenates, and these product mixtures are usually well-characterized. However, the analysis of Fischer–Tropsch waste water (FTW) is still somewhat underdeveloped and the exact composition of FTW remains unclear. Herein, various qualitative NMR techniques, especially diffusion-ordered spectroscopy (DOSY) and one dimension (1D) selective gradient total correlation spectroscopy (SelTOCSY) were strategically applied in the analysis of FTW. The NMR results show that the DOSY technique can pseudo-separate most of components in complex mixtures over the diffusion dimension. The SelTOCSY technique is used as a supporting method in the cases where the DOSY technique cannot clearly distinguish overlapped signals. Moreover, the quantitative 1 H NMR (qNMR) was further used to quantify the components of the sample. These routine and advanced qualitative and quantitative NMR technique utilized here provide a fast, effective and feasible method for the identification of complex mixtures in FTW, which might be a powerful and fast alternative to gas chromatography or high performance liquid chromatography for FTW research.
研究领域:
化学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Magnetic Resonance Letters
·
2021
·
IF 0
Hui Ma,Christian M. Pedersen,Qi Zhao,Shiyu Jia,Bin Yuan,Xianglin Hou,Yingxiong Wang
Coal chemical wastewater (CCW) with the features of high toxicity and poor biodegradability is a big issue in environmental remediation, posing a great threat to aquatic ecosystems and to human beings. Such complex molecular mixtures are notoriously difficult to characterize without initial physical separation. Herein, we present the 3D diffusion ordered spectroscopy (DOSY) analysis for CCW using DOSY-COSY and DOSY-HSQC methods, the advantages of this strategy have been demonstrated in the analysis of mixtures of aliphatic oxygenates and aromatic compounds, before being implemented on a genuine CCW sample in this study. The results showed that 3D DOSY is a robust and reliable tool for providing superior resolution and virtual separation of complex pollutants, and can be used as a general approach for structural elucidation.
研究领域:
环境科学
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分析化学
·
污染控制
✓ 已验证
DOI
JOURNAL OF MOLECULAR LIQUIDS
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2021
·
IF 6.165
Hui Ma,Dan Luo,Qi Zhao,Rui Liu,Zhenzhou Zhang,Xianglin Hou,Xiaohuan Sun,Yingxiong Wang
Diffusion-ordered spectroscopy (DOSY) is a powerful and efficient technique for the analysis of complex mixtures, relying on their differential in self-diffusion coefficient. However, DOSY is often struggled to separate signals pertaining to isomeric species, especially positional isomers. Here, for the first time, we describe the novel design of 18-crown ether-6 (18C6) and 18C6/K + complex as matrixes to discriminate and identify positional isomeric mixtures of phenylenediamine, nitroaniline, phthalic acid, dimethoxybenzoic acid, aminophthalic acid and even amino acids using 1 H DOSY spectrum. The superior performance of 18C6 and 18C6/K + complex as matrix depends on that they can interact with different components with varying binding energy as demonstrated by MMMF calculations and the DFT calculation. The methodology presented here is simple yet efficient. Moreover, the crown ether and crown ether/K + complex provide the dual mode discrimination for both amino and carboxylic substituted positional isomers.
研究领域:
分析化学
·
物理化学
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产品关联
DOI
高影响因子
ENERGY & FUELS
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2018
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IF 3.024
Zexiang Lyu,Fen-e Gao,Lizhu Wen,Kemeng Shi,Minjun Ma,Chunju Li,Yingxiong Wang,Yan Qiao
Analyzing the mixtures obtained from hydrogenation or hydrogenolysis reactions of biomass-derived platform chemicals is challenging work. With the development and improvement of NMR techniques, the NMR spectrometer proves to be an alternative and highly efficient piece of equipment for the rapid analysis of complex mixtures without the need for tedious purification. Herein, diffusion-ordered spectroscopy (DOSY) is applied in analyzing four model mixtures, which consist of the reactants and products from hydrogenation/hydrogenolysis reactions of biomass-derived platform chemicals. The results show that the DOSY technique can pseudoseparate most components in the model mixtures. The 1D selective gradient TOCSY technique is used as a supporting tool in the cases where the DOSY technique cannot clearly distinguish between the components of the mixtures. This is generally a problem when components in the mixture have very similar diffusion coefficients or severe overlap of peaks. The results show that DOSY and 1D selective gradient TOCSY techniques make a strong combination for complex mixture analyses.
研究领域:
分析化学
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生物化学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL CHEMISTRY
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2022
·
IF 8.008
Anqi He,Lei Ni,Hui Fu,Xiu Zhang,Zhen-Qiang Yu,Jun Song,Limin Yang,Yizhuang Xu,Yukihiro Ozaki,Isao Noda
When diffusion coefficients of different components in a mixture are similar, NMR spectra of pure individual components are difficult to be obtained via a diffusion-ordered spectroscopy (DOSY) experiment. Two-dimensional correlation spectroscopy (2D-COS) is used to analyze the data from the DOSY experiment. Through the properties of the systematic absence of cross-peak (SACP) in the 2D asynchronous spectra, spectra of pure components can be obtained even if their diffusion coefficients are similar. However, fluctuations in peak-position and peak-width are often unavoidable in NMR spectra, which makes SACPs unrecognizable. To address the problem, a 2D quotient spectrum is used to identify the masked SACPs. However, undesirable interference peaks due to the fluctuations in peak-position and peak-width are still present when we extract a spectrum of a component by slicing the 2D asynchronous spectrum across the SACP. A genetic algorithm (GA) is used to select a suitable subset of spectra where the diversities of peak-position and peak-width are significantly reduced. Then, we used the selected spectra to construct a refined 2D asynchronous spectrum so that the spectra of pure components with significant attenuated interference can be obtained. The above approach has been proven to be effective on a model system and a real-world example, demonstrating that 2D-COS possesses a bright perspective in the analysis of the bilinear data from DOSY experiments.
研究领域:
分析化学
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核磁共振波谱学
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数据分析
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产品关联
DOI
PubMed
高影响因子
Separations
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2022
·Vol. 9
·期 12
·388
·
IF 3.344
Yulin You,Dongxiao Guo,Weiliang Cui,Zhifan Wang,Chunguo Yang,Yongqiang Lin,Shuqi Wang
Matrix-assisted diffusion-ordered spectroscopy (MA DOSY) technology enables efficient the virtual separation of components in a mixture according to their coefficients (D). In the current research, MA DOSY technology was applied for the analysis of a flavonoid mixture. To establish the method, five representative active flavonoid ingredients, including baicalein, baicalin, quercetin, puerarin and rutinum, were selected for the mixture model. The effects of the type and concentration of the matrix, solvent polarity, and nuclear magnetic resonance (NMR) experimental conditions on the resolution of the DOSY spectrum were investigated. It turned out that sodium dodecyl sulfate (SDS) showed the best performance in increasing the resolution of different analytes, which initially increased to the peak below the added amount of 9 mg, and decreased upon the addition of more SDS. In addition, the five flavonoids showed higher resolution in DMSO–d6than in MeOD. Experimental parameters of DOSY, including the number of scans (NS), dummy scans (DS), and value of the FID data points (TD), were also optimized. Finally, the above optimized method was used for the qualitative analysis of the total flavonoid mixture extracted fromScutellaria baicalensisGeorgi. A total of nine compounds were identified and confirmed by comparing them with mass spectrometry data, which further verifies the practical value of this method upon analyzing flavonoid mixtures and provides some reference significance for the follow-up research.Keywords:NMR;MA-DOSY;flavonoids;mixture separation
研究领域:
分析化学
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药学
·
天然产物化学
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产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2018
·
IF 3.956
Zexiang Lyu,Fen Yue,Xiuyin Yan,Jianfeng Shan,Danlei Xiang,Christian Marcus Pedersen,Chunju Li,Yingxiong Wang,Yan Qiao
Hydrogenolysis is necessary for preparing various value-added chemicals from glycerol. Routine methods like GC and HPLC are not sufficient for analysis the reaction mixtures because the products usually have high boiling or similar polarity, especially when new chromatographic peaks are found which requires other technologies such as NMR . Although they were developed for years, but either DOSY or 1D selective TOCSY NMR has nature limitations. Herein we took their advantages and combined them to analyse glycerol hydrogenolysis mixtures for the first time. A model reaction mixture was first pseudo separated in DOSY spectrum, and 1D selective gradient TOCSY was further applied to assign the overlapped signal which could not be confirmed just by DOSY. A genuine reaction mixture was tried afterwards, and main signals could be assigned well in DOSY diffusion dimension. Notably, n-propanol was found as by-product by 1D selective gradient TOCSY, which is not visible in DOSY spectrum. The experimental results demonstrate that the combination of these two NMR methods could provide a fast, effective, feasible and reliable way for the identification of glycerol hydrogenolysis mixtures and is expected to apply in other research areas.
研究领域:
化学
·
生物化学
·
分析化学
✓ 已验证
DOI
高影响因子
PHYTOCHEMICAL ANALYSIS
·
2025
·
IF 2.6
Shanghong Li,Cuifen Fang,Sinan Wang,Hsiuting Chang,Cheng Zheng,Yi Wang,Yu Tang
Introduction Despite significant advances in analytical methods, the quality evaluation and adulteration detection of chemically complex traditional Chinese medicines continues to be a major challenge. Objectives We developed a custom diffusion-ordered spectroscopy (DOSY) approach for the qualitative analysis of precious Calculus Bovis (CB) and detection of its adulterants. Methods Using Artificial Calculus Bovis as an example, we focused on the effects of NMR spectrometers, solvent viscosity, matrices, matrix concentration, and temperature on separation efficiency of DOSY. The optimal conditions also successfully applied for the identification of Natural Calculus Bovis, Calculus Bovis Sativus, and adulterated samples. The accuracy of DOSY was verified by 13 C NMR. Results Via inspection of NMR spectrometers, solvents, matrices, matrix concentration, and temperature, the optimal conditions for DOSY experiments of CB were found to be using methanol- d 4 as the solvent, adding 4 mg of polyvinyl pyrrolidone (PVP) as the matrix, and a temperature of 298 K. Under these conditions, five types of compounds, cholic acid (CA), deoxycholic acid (DCA), hyodeoxycholic acid (HDCA), taurine-conjugated bile acids (tBAs), and glycine-conjugated bile acids (gBAs), were unequivocally identified in three types of CB. 13 C NMR validated the accuracy of the DOSY results. As for the sugar-adulterated CB, the signals of sugar could be clearly identified on the DOSY spectrum. Conclusions This study verified the feasibility of DOSY for the quality evaluation of CB and provided a reference point for future qualitative and quantitative analysis of other complex traditional Chinese medicines, as well as the characterization of adulterated samples.
研究领域:
中药学
·
分析化学
✓ 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）