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Effect of ligand chain length on hydrophobic charge induction chromatography revealed by molecular dynamics

Lin ZHANG, Yan SUN

《化学科学与工程前沿（英文）》 2013年 第7卷 第4期   页码 456-463 doi: 10.1007/s11705-013-1357-y

摘要： Hydrophobic charge induction chromatography (HCIC) is a mixed-mode chromatography which is advantageous for high adsorption capacity and facile elution. The effect of the ligand chain length on protein behavior in HCIC was studied. A coarse-grain adsorbent pore model established in an earlier work was modified to construct adsorbents with different chain lengths, including one with shorter ligands (CL2) and one with longer ligands (CL4). The adsorption, desorption, and conformational transition of the proteins with CL2 and CL4 were examined using molecular dynamics simulations. The ligand chain length has a significant effect on both the probability and the irreversibility of the adsorption/desorption. Longer ligands reduced the energy barrier of adsorption, leading to stronger and more irreversible adsorption, as well as a little more unfolding of the protein. The simulation results elucidated the effect of the ligand chain length, which is beneficial for the rational design of adsorbents and parameter optimization for high-performance HCIC.

关键词： adsorption     desorption     irreversibility     protein conformational transition     molecular dynamics simulation    

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Molecular size characterization of heavy oil fractions in vacuum and solution by molecular dynamic simulation

Wenpo REN, Honggang CHEN, Chaohe YANG, Honghong SHAN,

《化学科学与工程前沿（英文）》 2010年 第4卷 第3期   页码 250-256 doi: 10.1007/s11705-009-0281-7

摘要： Two kinds of heavy oils were fractionated into eight fractions by Liquid-Solid Adsorption Chromatography, respectively, and samples were collected to measure properties. According to the elemental analysis, molecular weight and H-NMR data, average molecular structures of polycyclic aromatic and heavy resin were constructed with improved Brown-Ladner (B-L) method and several corrections. And then, the most stable conformations of polycyclic aromatic and heavy resin in vacuum and toluene solution were obtained by molecular dynamic simulation, and the molecular size was gotten via the radius of gyration analysis. The results showed that the radius of gyration of polycyclic aromatic and heavy resin was 0.55–0.70 nm in vacuum and 0.60–0.90 nm in toluene solution. With molecular weight increasing, the molecular size in vacuum and toluene solution also increased. Due to the swelling behavior of solvent, the alkyl side chains of heavy oil molecule in solution were more stretched. Thus, the molecular size in toluene solution was larger than that in vacuum.

关键词： dynamic simulation     molecular dynamic     behavior     molecule     Adsorption Chromatography    

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Application of high-speed counter-current chromatography coupled with high performance liquid chromatography

Shengguo DENG, Zeyuan DENG, Yawei FAN, Jing LI, Rong LIU, Dongmei XIONG,

《化学科学与工程前沿（英文）》 2009年 第3卷 第4期   页码 375-382 doi: 10.1007/s11705-009-0247-9

摘要： Quercetin-3--sambubioside Quercetin-3--β-D-xylopyranosyl (1→2)-β-D-glucopyranoside was separated and purified by semi-preparative high-speed counter-current chromatography (HSCCC) with a two-phase-solvent system composed of ethyl acetate-n-butanol–water (4∶1∶5, v/v) from the leaves of (Lotus). A total of 5.0mg of the targeted compound with a purity of 98.6% as determined by high performance liquid chromatography (HPLC) was obtained from 100m g of the crude extract cleaned up by AB-8 macroporous resin in a one-step separation. Quercetin-3--sambubioside was a novel flavonoid glycoside from the leaves of , and its chemical structure was identified by means of ESI-MS, 1D NMR and 2D NMR.

关键词： two-phase-solvent     flavonoid glycoside     high-speed counter-current     macroporous     counter-current chromatography    

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isopropylacrylamide with 3-(methacryloxy)propyl trimethoxysilane on ultrafine silica and its application in chromatography

ZHANG Liping, ZHU Yi, NI Caihua

《化学科学与工程前沿（英文）》 2008年 第2卷 第3期   页码 242-247 doi: 10.1007/s11705-008-0043-y

摘要： Thermosensitive core-shell particles were synthesized through graft copolymerization of -isopropylacrylamide with [ 3-(methacryloxy) propyl]trimethoxysilane (MPT) coupled on the surface of ultrafine silica beads. The copolymerization was carried out using polyvinyl alcohol as a surfactant, water and cyclohexanol as mixed solvent, and 2,2′-azobis(isobutyronitrile) as an initiator. The effect of surfactant concentration and the composition of the mixed solvent on the graft rate were investigated. The structure of modified silica was confirmed by infrared spectra. Differential scanning calorimetry (DSC) has revealed the thermosensitivity of the particles. The thermosensitive particles were used as packing materials of high performance liquid chromatography (HPLC) columns for separating naphthalene derivatives. Satisfactory separation was obtained by controlling the temperature of the column. In contrast, the packing material of silica-MPT has no such separation efficiency due to the lack of thermosensitivity. The effect of the composition of the mobile phase on the separating efficiency was also investigated. The temperature-controlled separation was effective only when the water content was higher than 90% (v/v) in the water-methanol mobile phase. The mechanism for the temperature-controlled separation is attributed to a polarity change of poly(-isopropylacrylamide) which undergoes volume phase transition on the silica surface as the temperature increases.

关键词： undergoes     water-methanol     surfactant concentration     copolymerization     chromatography    

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Fast determination of tobramycin by reversed-phase ion-pair high performance liquid chromatography with

Liang ZHU, Jingkang WANG

《化学科学与工程前沿（英文）》 2013年 第7卷 第3期   页码 322-328 doi: 10.1007/s11705-013-1348-z

摘要： A simple and direct method without a derivation step for routine analysis of tobramycin has been developed. This method used reversed-phase ion-pair high performance liquid chromatography (HPLC) with a refractive index (RI) detector and a C18 column which is stable at pH above 1.00. The presence of 4.50 mg·mL trifluoroacetic acid (TFA) in the mobile phase improved the protonation of tobramycin and the formation of ion-pairs, and thus reduced its hydrophility. This unique separation–detection combination showed good linearity with correlation coefficients 0.9996 in the concentration range of 0.25–2.50 mg·mL . The quantitation limit and detection limit were determined to be 0.23 mg·mL and 0.071 mg·mL , respectively. Tobramycin was recovered in 98.00%, 98.84% and 99.64% for tobramycin solutions at concentrations of 2.25 mg·mL , 1.50 mg·mL and 0.75 mg·mL , respectively. The relative standard deviations for six spiked samples ranged from 0.20% to 2.40%, indicating a good reproducibility of this method.

关键词： tobramycin     aminoglycoside     refractive index detector     high-performance liquid chromatography     ion-pairing    

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Simultaneous analysis of five taste and odor compounds in surface water using solid-phase extraction and gas chromatography-mass

Wenfeng SUN, Ruibao JIA, Baoyu GAO

《环境科学与工程前沿（英文）》 2012年 第6卷 第1期   页码 66-74 doi: 10.1007/s11783-010-0257-3

摘要： In this paper, a method using solid-phase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS) was developed to simultaneously analyze five taste and odor compounds in surface water, i.e., 2-methylisoborneol (2-MIB), 2,4,6-trichloroanisole (TCA), 2-isopropyl-3-methoxy pyrazine (IPMP), 2-isobutyl-3-methoxy pyrazine (IBMP), and -1,10-dimethyl- -9-decalol (geosmin, GSM). The mass spectrometry was operated in selective ion monitoring (SIM) mode. Three kinds of SPE columns and three eluting solvents were compared, the C18 column was chosen as optimum SPE column, and methanol was chosen as the optimum eluting solvent. It was found that the method showed good linearity in the range of 1–200 ng·L and gave detection limits of 0.5–1.5 ng·L for individual compounds. Good recoveries (93.5%–108%) and relative standard deviations (1.58%–7.31%) were also obtained. Additionally, concentrations of these taste and odor compounds in Jinan’s surface and drinking water were analyzed by applying this method, and the results showed that GSM and 2-MIB were the dominant taste and odor compounds in Jinan’s raw water.

关键词： solid-phase extraction (SPE)     gas chromatography-mass spectrometry (GC-MS)     taste and odor compounds     surface water     micropollutant    

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Simultaneous quantification of several classes of antibiotics in water, sediments, and fish muscles by liquid chromatography–tandem

WEI Yimei,ZHANG Yuan,XU Jian,GUO Changsheng,LI Lei,FAN Wenhong

《环境科学与工程前沿（英文）》 2014年 第8卷 第3期   页码 357-371 doi: 10.1007/s11783-013-0580-6

摘要： Precise and sensitive methods for the simultaneous determination of different classes of antibiotics, including sulphonamides, fluoroquinolones, macrolides, tetracyclines, and trimethoprim in surface water, sediments, and fish muscles were developed. In water samples, drugs were extracted with solid-phase extraction (SPE) by passing 1000 mL of water through hydrophilic lipophilic balanced (HLB) SPE cartridges. Sediment samples were solvent-extracted, followed by tandem SPE (strong anion exchange (SAX) + HLB) clean-ups. Fish muscles were extracted by a mixture of acetonitrile and citric buffer (80:20, v/v) solution, and cleaned by SPE. Liquid chromatography–tandem mass spectrometry (LC-MS/MS) with multiple reaction monitoring (MRM) detection was employed to quantify all compounds. The recoveries for the antibiotics in the spiked water, sediment, and fish samples were 60.2%–95.8%, 48.1%–105.3%, and 59.8%–103.4%, respectively. The methods were applied to samples taken from Dianchi Lake, China. It showed that concentrations of the detected antibiotics ranged from limits of quantification (LOQ) to 713.6 ng·L (ofloxacin) in surface water and from less than LOQ to 344.8 μg·kg (sulphamethoxazole) in sediments. The number of detected antibiotics and the overall antibiotic concentrations were higher in the urban area than the rural area, indicating the probable role of livestock and human activities as important sources of antibiotic contamination. In fish muscles, the concentration of norfloxacin was the highest (up to 38.5 μg·kg ), but tetracyclines and macrolides were relatively low. Results showed that the methods were rapid and sensitive, and capable of determining several classes of antibiotics from each of the water, sediment, and fish matrices in a single run.

关键词： antibiotics     liquid chromatography–tandem mass spectrometry (LC-MS/MS)     water     sediment     fish muscle    

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analysis of off-flavor/odor compounds in water using liquid-liquid microextraction coupled with gas chromatography—positive

Jian LU,Paul S. WILLS,P. CHRIS WILSON

《环境科学与工程前沿（英文）》 2016年 第10卷 第3期   页码 477-481 doi: 10.1007/s11783-015-0820-z

摘要： A rapid, inexpensive and laboratory friendly method was developed for analysis of off-flavor/odor compounds in fresh and salt water using gas chromatography with chemical ionization-tandem mass spectrometry. Off-flavor/odor compounds included geosmin, 2-methylisoborneol (MIB), 2-isobutyl-3-methyoxypyrazine (IBMP), and 2-isopropyl-3-methoxypyrazine (IPMP). Using this method, a single sample can be extracted within minutes using only 1 mL of organic solvent. The ion transitions for IPMP, IBMP, MIB, and geosmin were 153>121, 167>125, 152>95, and 165>109, respectively. The linearity of this method for analyzing MIB ranged from 4 to 200 ng·L , and from 0.8 to 200 ng·L for the other analytes. Method recoveries ranged from 97% to 111% and percent relative standard deviations ranged from 3% to 9%, indicating that the method is accurate, precise, and reliable.

关键词： off-flavor/odor compounds     liquid-liquid microextraction     gas chromatography-tandem mass spectrometry    

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organic compounds in water using automated online solid-phase extraction with large-volume injection/gas chromatography

Yongtao LI, Christina L. MCCARTY, Ed J. GEORGE

《环境科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 417-425 doi: 10.1007/s11783-011-0310-x

摘要： A rapid, sensitive, and cost-effective analytical method was developed for the analysis of selected semi-volatile organic compounds in water. The method used an automated online solid-phase extraction technique coupled with programmed-temperature vaporization large-volume injection gas chromatography/mass spectrometry. The water samples were extracted by using a fully automated mobile rack system based on x-y-z robotic techniques using syringes and disposable 96-well extraction plates. The method was validated for the analysis of 30 semi-volatile analytes in drinking water, groundwater, and surface water. For a sample volume of 10 mL, the linear calibrations ranged from 0.01 or 0.05 to 2.5μg·L , and the method detection limits were less than 0.1μg·L . For the reagent water samples fortified at 1.0μg·L and 2.0?μg·L , the obtained mean absolute recoveries were 70%–130% with relative standard deviations of less than 20% for most analytes. For the drinking water, groundwater, and surface water samples fortified at 1.0μg·L , the obtained mean absolute recoveries were 50%–130% with relative standard deviations of less than 20% for most analytes. The new method demonstrated three advantages: 1) no manipulation except the fortification of surrogate standards prior to extraction; 2) significant cost reduction associated with sample collection, shipping, storage, and preparation; and 3) reduced exposure to hazardous solvents and other chemicals. As a result, this new automated method can be used as an effective approach for screening and/or compliance monitoring of selected semi-volatile organic compounds in water.

关键词： automated solid-phase extraction     programmed-temperature vaporization     large-volume injection     gas chromatography/mass spectrometry     semi-volatile organic compounds     water analysis    

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Tetra-detector size exclusion chromatography characterization of molecular and solution properties of

Qingbin Guo,Sheng Chang

《环境科学与工程前沿（英文）》 2017年 第11卷 第2期 doi: 10.1007/s11783-017-0922-x

摘要： Tetra-detector HPSEC was evaluated for the SMP characterization Molecular weight and intrinsic viscosity of the SMP were characterized Specific viscosity and osmotic pressure of the SMP solution were studied Approach to analyze the concentration polarization of the SMP was discussed Characterization of the molecular properties of soluble microbial products (SMP) is critical for understanding the membrane filtration and fouling mechanisms in anaerobic and aerobic membrane bioreactors (AnMBR & MBR). In this study, the distributions of the absolute molecular weight and intrinsic viscosity of SMP polysaccharides from an AnMBR were effectively determined by a high performance size exclusion chromatography (HPSEC) that was coupled with the refractive index (RI), diode array UV (DAUV), right and low angle light scattering (LS), and viscometer (Vis) detectors. Based on the tetra-detector HPSEC determined absolute molecular weights and intrinsic viscosity, a universal calibration relationship for the SMP polysaccharides was developed and the molecular conformations, average molecular weights, and hydrodynamic sizes of the SMP polysaccharides were also explored. Two factors which can be derived from the tetra-detector HPSEC analysis were proposed for the characterization of the viscous and osmotic pressure properties of the SMP polysaccharides. In addition, it was also extrapolated how to analyze the resistance characteristics of the concentration polarization layers formed in membrane filtration based on the molecular properties determined by the tetra-detector HPSEC analysis.

关键词： Soluble microbial product     Extracellular polymeric substance     Membrane bioreactor     Membrane fouling     Molecular weight     Intrinsic viscosity    

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Continuous size fractionation of magnetic nanoparticles by using simulated moving bed chromatography

Carsten-Rene Arlt, Dominik Brekel, Stefan Neumann, David Rafaja, Matthias Franzreb

《化学科学与工程前沿（英文）》 2021年 第15卷 第5期   页码 1346-1355 doi: 10.1007/s11705-021-2040-3

摘要： The size fractionation of magnetic nanoparticles is a technical problem, which until today can only be solved with great effort. Nevertheless, there is an important demand for nanoparticles with sharp size distributions, for example for medical technology or sensor technology. Using magnetic chromatography, we show a promising method for fractionation of magnetic nanoparticles with respect to their size and/or magnetic properties. This was achieved by passing magnetic nanoparticles through a packed bed of fine steel spheres with which they interact magnetically because single domain ferro-/ferrimagnetic nanoparticles show a spontaneous magnetization. Since the strength of this interaction is related to particle size, the principle is suitable for size fractionation. This concept was transferred into a continuous process in this work using a so-called simulated moving bed chromatography. Applying a suspension of magnetic nanoparticles within a size range from 20 to 120 nm, the process showed a separation sharpness of up to 0.52 with recovery rates of 100%. The continuous feed stream of magnetic nanoparticles could be fractionated with a space-time-yield of up to 5 mg/(L∙min). Due to the easy scalability of continuous chromatography, the process is a promising approach for the efficient fractionation of industrially relevant amounts of magnetic nanoparticles.

关键词： magnetic chromatography     simulated moving bed chromatography     magnetic nanoparticles     size fractionation    

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Contributions of adsorption, bioreduction and desorption to uranium immobilization by extracellular polymeric

《环境科学与工程前沿（英文）》 2023年 第17卷 第9期 doi: 10.1007/s11783-023-1707-z

摘要：

● EPS immobilizes U(VI) via adsorption, bioreduction and desorption.

关键词： Adsorption     Bioreduction     Desorption     Kinetics     Isotherm     Uranium    

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Determination of persistent organic pollutants by gas chromatography/laser multiphoton ionization/time-of-flight

Osamu SHITAMICHI, Taiki MATSUI, Yamei HUI, Weiwei CHEN, Totaro IMASAKA

《环境科学与工程前沿（英文）》 2012年 第6卷 第1期   页码 26-31 doi: 10.1007/s11783-011-0374-7

摘要： An authentic mixture of polychlorinated biphenyls was measured using a short wide-bore capillary column for the group separation of major components present in an actual sample of Kanechlor. The limits of detection were improved by ca. 2 fold in comparison with those obtained using a conventional capillary column, since the retention time was reduced and the amount of analytes introduced into the mass spectrometer per unit time could be increased. On the other hand, surface-water and sediment samples containing polycyclic aromatic hydrocarbons (PAHs) were collected from the river located in the vicinity of a waste water treatment plant. Even acenaphthylene, a minor component of the mixture could be measured for the sediment sample, and the concentrations were determined for several heavy PAHs. As demonstrated, a technique involving laser multiphoton ionization/time-of-flight mass spectrometry was useful as a sensitive and selective analytical tool for the trace analysis of persistent organic pollutants in an environmental sample.

关键词： polychlorinated biphenyls (PCBs)     polycyclic aromatic hydrocarbons (PAHs)     laser multiphoton ionization/time-of-flight mass spectrometry (MPI/TOF-MS)    

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Polypropylene microplastics alter the cadmium adsorption capacity on different soil solid fractions

《环境科学与工程前沿（英文）》 2022年 第16卷 第1期   页码 3-3 doi: 10.1007/s11783-021-1437-z

摘要：

Microplastics (MPs) are widely present in a variety of environmental media and have attracted more and more attention worldwide. However, the effect of MPs on the interaction between heavy metals and soil, especially in soil solid fraction level, is not well understood. In this study, batch experiments were performed to investigate the adsorption characteristics of Cd in bulk soil and three soil solid fractions (i.e. particulate organo matter (POM), organic-mineral compounds (OMC), and mineral) with or without polypropylene (PP) MPs.

关键词： Polypropylene microplastics     Cadmium     Adsorption     POM     OMC     Mineral    

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Cesium removal from radioactive wastewater by adsorption and membrane technology

《环境科学与工程前沿（英文）》 2023年 第18卷 第3期 doi: 10.1007/s11783-024-1798-1

摘要：

● Removal of cesium from radioactive wastewater is still a challenging.

关键词： Cesium     Adsorption     Membrane separation     Advanced liquid processing system     Fukushima nuclear accident    

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标题 作者 时间 类型 操作

Effect of ligand chain length on hydrophobic charge induction chromatography revealed by molecular dynamics

Lin ZHANG, Yan SUN

期刊论文

Molecular size characterization of heavy oil fractions in vacuum and solution by molecular dynamic simulation

Wenpo REN, Honggang CHEN, Chaohe YANG, Honghong SHAN,

期刊论文

Application of high-speed counter-current chromatography coupled with high performance liquid chromatography

Shengguo DENG, Zeyuan DENG, Yawei FAN, Jing LI, Rong LIU, Dongmei XIONG,

期刊论文

isopropylacrylamide with 3-(methacryloxy)propyl trimethoxysilane on ultrafine silica and its application in chromatography

ZHANG Liping, ZHU Yi, NI Caihua

期刊论文

Fast determination of tobramycin by reversed-phase ion-pair high performance liquid chromatography with

Liang ZHU, Jingkang WANG

期刊论文

Simultaneous analysis of five taste and odor compounds in surface water using solid-phase extraction and gas chromatography-mass

Wenfeng SUN, Ruibao JIA, Baoyu GAO

期刊论文

Simultaneous quantification of several classes of antibiotics in water, sediments, and fish muscles by liquid chromatography–tandem

WEI Yimei,ZHANG Yuan,XU Jian,GUO Changsheng,LI Lei,FAN Wenhong

期刊论文

analysis of off-flavor/odor compounds in water using liquid-liquid microextraction coupled with gas chromatography—positive

Jian LU,Paul S. WILLS,P. CHRIS WILSON

期刊论文

organic compounds in water using automated online solid-phase extraction with large-volume injection/gas chromatography

Yongtao LI, Christina L. MCCARTY, Ed J. GEORGE

期刊论文

Tetra-detector size exclusion chromatography characterization of molecular and solution properties of

Qingbin Guo,Sheng Chang

期刊论文

Continuous size fractionation of magnetic nanoparticles by using simulated moving bed chromatography

Carsten-Rene Arlt, Dominik Brekel, Stefan Neumann, David Rafaja, Matthias Franzreb

期刊论文

Contributions of adsorption, bioreduction and desorption to uranium immobilization by extracellular polymeric

期刊论文

Determination of persistent organic pollutants by gas chromatography/laser multiphoton ionization/time-of-flight

Osamu SHITAMICHI, Taiki MATSUI, Yamei HUI, Weiwei CHEN, Totaro IMASAKA

期刊论文

Polypropylene microplastics alter the cadmium adsorption capacity on different soil solid fractions

期刊论文

Cesium removal from radioactive wastewater by adsorption and membrane technology

期刊论文