ELECTROPHORESIS
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2021
·Vol. 42
·期 24
·2664-2671
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IF 3.535
Wei Zhou,Xinhong Yu,Yikun Liu,Wenqi Sun,Zilin Chen
Enhancing the specific surface area of stationary phase is important in chromatographic science, especially in open-tubular column in which the coating only exists on the inner surface. In this work, a porous layer open-tubular (PLOT) column with stationary phase of styrene and itaconic acid-copolymerized polymer was developed. Thermal-initiated polymerization method with strategies like controlling the ratio of reaction reagents to solvents and reaction time, confinement by the narrow inner diameter of capillary were used for preparing the stationary phase with uniform structure and relatively thick layer. Due to the high separation efficiency and capacity, the PLOT column was used for capillary electrochromatography (CEC) separation of multiple groups of analytes like alkylbenzenes, phenyl amines, phenols, vanillins, and sulfonamides with theoretical plates (N) up to 1,54,845 N/m. In addition, due to high permeability of the CEC column and large electroosmotic flow mobility generated by abundant carboxyl groups in the coating material, the PLOT-CEC column was successfully coupled with mass spectrometry (MS) through a sheath flow interface. The developed PLOT-CEC-MS method was used for the analysis of antiseptics like parabens and herbicides like pyridines.
研究领域:
分析化学
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分离科学
✓ 已验证
DOI
高影响因子
ELECTROPHORESIS
·
2018
·Vol. 39
·期 7
·941-947
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IF 2.569
Li Zhou,Shenmeng Jiang,Xue Zhang,Linlin Fang,Xingjie Guo
In this paper, β-cyclodextrin (β-CD) modified gold nanoparticles (AuNPs) coated open tubular column (OT column) was prepared for capillary electrochromatography. The open tubular column was constructed through self-assembly of gold nanoparticles on 3-mercaptopropyl-trimethoxysilane (MPTMS) prederivatized capillary and subsequent modification of thiols β-cyclodextrin (SH-β-CD). Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ultraviolet visible spectroscopy were carried out to characterize the prepared open tubular column and synthesized gold nanoparticles. By comparing different coating times of gold nanoparticles and thiols β-cyclodextrin, we got the optimal conditions for preparing the open tubular column. Also, the separation parameters were optimized including buffer pH, buffer concentration and applied voltage. Separation effectiveness of open tubular column was verified by the separation of four pairs of drug enantiomers including bifonazole, fexofenadine, omeprazole and lansoprazole, and satisfactory separation results were achieved for these analytes studied. In addition, the column showed good stability and repeatability. The relative standard deviation values less than 5% were obtained through intra-day, inter-day, and column-to-column investigations.
研究领域:
分析化学
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药学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TALANTA
·
2019
·
IF 4.916
Wei Zhou,Wenqi Sun,Yikun Liu,Zhenkun Mao,Zilin Chen
Developing novel capillary electrochromatography (CEC) column with high separation efficiency and capacity is an essential work in CEC. In this work, porous layer open tubular (PLOT) column has been developed by co-polymerization of quaternary ammonium typed ionic liquid (IL), 1-allyl-methylimidazolium chloride (AlMeIm + Cl − ) with styrene (IL-styrene) and ethylene dimethacrylate (EDMA) for CEC-MS analysis. The PLOT-CEC column possesses high separation efficiency and capacity while keeping the inherent advantages of open tubular (OT) column unaltered, which is suitable for CEC analysis. Due to the uniform branch-like structure with large specific surface area, the IL-styrene based PLOT-CEC column showed excellent separation efficiency towards multiple kinds of analytes with theoretical plates up to N = 322,277 N/m for phloroglucinol . And thanks to the high permeability and large EOF mobility generated by positively charged ionic liquid, the PLOT-CEC column showed good performance in CEC-MS analysis of parabens , amino acids and peptides with stable separation and ESI spray . Good repeatability with relative standard deviations for intra-day, inter-day runs and between tubes less than 4.94% was obtained.
研究领域:
分析化学
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生物分析
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TALANTA
·
2016
·
IF 4.035
Tao Bao,Pingxiu Tang,Zhenkun Mao,Zilin Chen
A novel capillary column with metal-organic framework-5 (MOF-5) as the stationary phase was prepared for open-tubular capillary electrochromatography (OT-CEC). To grow MOF-5, the fused-silica capillary was functionalized firstly using 3-aminopropyltriethoxysilane and glutaraldehyde as covalent linkers; and then MOF-5 would be immobilized on the inner wall of COOH-terminated capillary by epitaxial growth , to produce a MOF-5-modified capillary. The successful growth of MOF-5 has been characterized and confirmed by scanning electron microscopy, X-Ray diffraction and Fourier transform infrared spectra . The influence of pH value and methanol on electroosmotic flow (EOF) of the MOF-5-modified capillary column was investigated. The EOF showed a pH-dependent from anode to cathode. The immobilization of MOF-5 improved the interactions between analytes and layer on inner wall of the capillary. Excellent separations of substituted benzenes and acidic and basic analytes were obtained on the fabricated capillary columns. The MOF-5-modified capillary columns exhibited good repeatability, with relative standard deviations for intra-day, inter-day runs and column-to-column less than 1.87%, 3.53%, and 8.49%, respectively. Our successful application of MOF-5 paved the way for introducing series of dicarboxylate-based isoreticular MOFs to OT-CEC as novel stationary phase.
研究领域:
分析化学
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材料科学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF SEPARATION SCIENCE
·
2016
·Vol. 39
·期 19
·3736-3744
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IF 2.741
Li Peng,Manman Zhu,Lingyi Zhang,Haiyan Liu,Weibing Zhang
A 3 m zwitterionic polymeric porous layer open tubular column (3 m × 25 μm id × 375 μm od) with a polymeric porous layer thickness of 4 μm was fabricated by the copolymerization of [2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide and N , N ’-methylenebis(acrylamide). The effects of the diameter of the capillary, reaction temperature, and polymerization time on the preparation of the open tubular column were investigated. Characterized by scanning electron microscopy, the zwitterionic layer was observed to be rough and throughout the fused-silica capillary homogenously, which increased the phase ratio. The separation of neutral, basic, and acidic compounds demonstrates the strong hydrophilicity of the poly[2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide coating. In addition, the poly[2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide porous layer open tubular column was applied for the analysis of flavonoids from the rootstalk of licorice, revealing the potential in separating complex samples. The relative standard deviation of retention time for run-to-run ( n = 5), day-to-day ( n = 3), and column-to-column ( n = 3) of toluene, N , N -dimethylformamide, formamide, and thiourea were below 1.2%, exhibiting good repeatability.
研究领域:
分析化学
·
色谱技术
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2018
·
IF 3.716
Xin Liu,Shucheng Sun,Rongbin Nie,Jicheng Ma,Qishu Qu,Li Yang
We report a highly uniform porous layer open tubular (PLOT) column for capillary electrochromatography (CEC) analysis. The PLOT column is easily fabricated using a single-step in-situ biphasic reaction, producing homogeneous porous-layer modified surface with ∼240 nm thickness in a 50 μm-id capillary. CEC performance of the PLOT column has been investigated and optimized under various experimental parameters. Using a mixture of naphthalene and biphenyl as the test sample, we show that the PLOT column exhibits good separation efficiency with resolution >3.0 and theoretical plate numbers over 6 × 10 4 , as well as good intra-/inter-day repeatability and column-to-column repeatability. The column has been successfully applied for CEC analysis of three different types of samples without any further modification of the columns, including complicated peptide products from tryptic-digestion of proteins (lysozyme and BSA), β-blockers (basic samples) and polycyclic aromatic hydrocarbons (neutral samples). Efficient separation has been achieved, which could be attributed to the enhanced surface-to-volume ratio of the PLOT column that will increase the interaction between solid phase and mobile phase in CEC. In addition, base-line separation of neutral samples indicates the reversed phase chromatographic property of the PLOT column, which could be induced by the residue of hexadecyltrimethylammonium bromide used in the fabrication process. Our study show that the present PLOT column is a promising approach that can significantly enhance CEC separation efficiency and could be of potential value in analysis of various different samples.
研究领域:
分析化学
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生物分析
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产品关联
DOI
PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 44
·期 3
·1028-1035
·
IF 3.069
Xiaoshuang Zhao,Linzhen Liu,Na Li,Tingting Wang,Yuzhu Chai,Ziyue Yang,Jiannong Ye,Qingcui Chu,Li Chen
Novel open-tubular (OT) columns were prepared for the first time based on zeolite silica nanoparticles (SiO2NPs) as the nano coating materials. The main immobilization factors, including the size and concentration of zeolite SiO2NPs, the content of bovine serum albumin (BSA), heat temperature and time, were investigated to obtain OT columns with good stability and repeatability. Then, the separation performance of the prepared OT columns with/without BSA modifier was explored using capillary electrochromatography with an amperometric detection system. Under the optimum conditions, eight groups of model molecules, including homologues, structural isomers, epimers and enantiomers, underwent baseline separation in the prepared OT columns. The zeolite SiO2NPs-OT columns provided an efficiency of up to 108 200 plates m−1 for 4-chloro-2-methylaniline, and the OT column modified with BSA accomplished the separation and analysis of ephedrine and pseudoephedrine in ephedra herbs. The relative standard deviations of the migration time, peak area and resolution of the selected model analytes were within 8.4% for run-to-run, day-to-day, and column-to-column repeatability. Furthermore, the prepared OT columns could provide acceptable separation performance in a simple running buffer without any organic additives or surfactants, indicating their promising potential for isomer separation.
研究领域:
分析化学
·
纳米材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2022
·
IF 4.601
Zongping Jia,Chengying Du,Lulu Zhu,Zhonglai Wang
An alumina porous layer open-tubular (Al 2 O 3 PLOT) column coated with γ–alumina nanoparticles (20 nm) for highly volatile hydrocarbons (C1 to C5) separation was described. Relative to the coating of bulk alumina, this column was easily coated with dynamic method under 0.4 or 0.6 MPa for 0.53 mm or 0.32 mm capillary, respectively. And the thickness of coating layer could be tuned by repeating the coating process after column was dried and activated at 300 °C for 3 h. The effect of deactivation agents on the physicochemical properties of nano γ–alumina was characterized by X–ray diffraction (XRD) measurement and nitrogen adsorption–desorption isotherms. The influences of deactivation agents, film thickness, conditioning and column dimensions on the inertness, polarity, selectivity and elution order of C1 to C5 separation were investigated in detail. The crystallite structure and size of nano alumina were not affected by the deactivation agents and remained constant during the column making processes, whereas specific surface area, pore volume and average half pore width altered significantly. The specific surface area decreased to 125.4 m 2 g –1 or 174.0 m 2 g –1 and the average half pore size distributions decreased to 1.6–8.4 nm or 2.4–14.3 nm when it was deactivated with potassium chloride or sodium sulfate solution, respectively. The deactivation agents and its concentrations impacted significantly on the retention performance of column. The column deactivated with sodium sulfate solution exhibited stronger polarity and lower selectivity than which deactivated with potassium chloride solution although both columns showed good inertness. The length, internal diameter and film thickness of the column had less influence on the selectivity and resolution for C1 to C5 hydrocarbons separation, whereas the conditioning temperature and time had an obvious influence. The column had distinguished polarity and selectivity which was different from either bulk or commercial alumina columns. Typically, the hydrocarbons were baseline separated with resolutions ranging from 1.65 to 15.33 within 9 min under programmed temperature below 100 °C, and the tailing factors ranging from 1.02 to 1.07.
研究领域:
分析化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2020
·
IF 4.049
Qianqian Xu,Baogen Su,Zongbi Bao,Yiwen Yang,Qiwei Yang,Qilong Ren
Gas-liquid chromatography is an effective method to determine infinite dilution activity coefficients ( γ ∞ ). Wall-coated open-tubular (WCOT) column which offers more advantages over packed column should be a preferable column type; however, the small carrier gas flow rate and stationary phase amount in WCOT columns limit its application in the determination of γ ∞ . Mathematical strategy made some progress to avoid the quantification problem in the determination of γ ∞ by static-wall-coated open-tubular (SWCOT) columns. However, the previously reported strategy was based on the assumption that SWCOT column was geometrically an ideal hollow cylinder, which indeed deviates from the reality. In this study, without that assumption, we derived a new microgeometry-independent equation by using the relationship between the hold-up volume ( V M ) and the volume of stationary phase ( V L ), and used it to measure the γ ∞ of various organic solutes in two ionic liquids (ILs) 1‑butyl‑3-methylimidazolium dicyanamide and 1,3-dibutyronitrile-imidazolium bis((trifluoromethyl)sulfonyl)imide, both of which contain double cyano groups in the anion or cation. Phase loading study was adopted to eliminate the influence of interfacial adsorption to partition. The infinite dilution partial molar excess enthalpy, selectivity and capacity were directly calculated from the experimental γ ∞ values, and the linear solvation energy relationship (LSER) model was used to characterize the specific properties of both ILs. This new established equation will promote the application of SWCOT columns in thermodynamic measurement and benefit the fast screening of novel solvents for chemical separation processes.
研究领域:
化学热力学
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分离科学
·
分析化学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Pharmaceutical Analysis
·
2021
·
IF 4.769
Xiaodong Sun,Bing Niu,Qi Zhang,Qin Chen
Homochiral metal-organic frameworks (MOFs) have attracted considerable attention in many fields of research, such as chiral catalysis and chiral chromatography. However, only few homochiral MOFs can be effectively used in capillary electrochromatography (CEC) and their performances are far from adequate. In this study, we successfully synthesized achiral nanocrystalline MIL-53. A facile post-synthetic modification strategy was then implemented to functionalize the product, yielding a homochiral MOF: l -His-NH-MIL-53. This MOF was then employed as a chiral coating in open-tubular CEC mode (OT-CEC), and, as such, it exhibited high enantioselectivities for several racemic drugs. The homochiral MOF and the fabricated capillary coating were systematically characterized using transmission electron microscopy, scanning electron microscopy (with energy-dispersive X-ray spectrometry), Fourier-transform infrared spectroscopy, X-ray diffractometry, thermogravimetric analysis, circular dichroism spectroscopy, Brunauer-Emmett-Teller surface area measurements, and X-ray photoelectron spectroscopy. This study is expected to provide a new strategy for the design and establishment of MOF-based chiral OT-CEC systems.
研究领域:
分析化学
·
材料科学
·
色谱学
·
纳米技术
✓ 已验证
DOI
高影响因子
JOURNAL OF LIQUID CHROMATOGRAPHY & RELATED TECHNOLOGIES
·
2020
·
IF 0.992
Shiyun Tang,Yuanxing Duan,Feng Chang,Wei Jiang,Fengmei Zhang,Zhihua Liu,Yuting Yang,Chunbo Liu,Yingzhuang Chen
The porous layer open-tube (PLOT) columns, which were characterized by their considerable specific surface area and high permeability, have attracted a growing attention from researchers in liquid chromatography. In this work, a hydrophilic PLOT column rich in carboxylic acid functional groups was successfully synthesized in capillary with an inner diameter of 200 µm by thermally initiated aqueous two-phase polymerization. Methacrylic acid (MAA) areas monomers that responsible for the introduction of polar functional groups, and poly(ethylene glycol) diacrylate (PEGDA) are as cross-linker. The optimized PLOT column has a uniform, moderately thick porous layer, which is tightly bonded to the inner wall without any detachment. The hollow structure gives the PLOT column good permeability, which facilitates fast mass transfer. The systematical evaluations of the resulting PLOT columns were performed by using polar analytes including nucleosides, bases, amides, phenols and carboxylic acids. Those results demonstrated excellent separation performance for the small polar molecules. Compared to the poly(PEGDA) PLOT column, the hydrophilic retention of analytes on poly(PEGDA-co-MAA) porous layer open-tube column is significantly improved by the introduction of carboxylic acids. Furthermore, with modified nucleosides and chlorophenols being disease markers and the persistent pollutant of wide concern, respectively, the separation was optimized and the linear range of the quantitative analysis was examined for both targets. which indicates the potential application of such PLOT column for analysis of real samples.
研究领域:
分析化学
·
色谱技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2020
·
IF 4.049
Mingxuan Ma,Cheng Chen,Xinqi Zhu,Xiaoqi Li,Yingxiang Du,Liu Zhang,Jie Gan
New material zeolitic imidazolate framework-4, 5-imidazoledicarboxylic acid (ZIF-IMD) located on the pore surface of porous layer open-tubular (PLOT) column previously functionalized with N-(3-aminopropyl)-imidazole have been prepared via a layer-by-layer self-assembly strategy. This new ZIF-IMD coating hybrids are used as solid-phase carriers for chiral selector pepsin immobilization. The ZIF-IMD material was characterized by scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscope and X-ray diffraction. The synthesized pepsin@ZIF-IMD@POLT column achieved the baseline separation of hydroxychloroquine (HCQ), chloroquine (CHQ) and hydroxyzine (HXY) (the resolution of HCQ: 2.19; CHQ: 1.84; HXY: 1.53). Compared with the pepsin@PLOT column (without ZIF-IMD material), the chiral separation capability of the pepsin@ZIF-IMD@POLT column can be remarkably improved. Several key parameters including concentration of chiral selector, buffer pH, applied voltage and buffer concentration were systematically evaluated to provide the optimal enantioseparation condition. The relative standard deviations (RSDs) of intra-day, inter-day, column-to-column and inter-batch of migration time and Rs of the HCQ were evaluated in detail, respectively (RSD < 7.21%). Additionally, the potential mechanism of increased resolution was discussed in the article.
研究领域:
分析化学
·
材料科学
·
药物分析
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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）