JOURNAL OF CHROMATOGRAPHY A
·
2020
·
IF 4.049
Hanzhi Zhang,Chunli Lou,Jing Li,Jingwu Kang
A method for the preparation of an on-column ESI emitter used as the sheathless interface for coupling capillary electrophoresis (CE) with mass spectrometry (MS) was developed. The emitter was directly fabricated at the outlet end of the separation capillary which was etched with HF solution to a symmetrical tip. The tip was covered with a small piece of gold foil which was fixed by epoxy resin glue for electrical contact. Such a prepared ESI emitter can produce a stable ESI signal over the wide range of flow rate from 50 nL/min to 800 nL/min. The performance of the CE-MS with the sheathless interface was evaluated by using the separation of four alkaloids. It was found that the strong electroosmotic flow produced by the multiple polyelectrolyte coating on the capillary is necessary for maintaining a stable MS signal. Effect of the running buffer composition, concentration and the CE separation voltages on the ESI signal strength were investigated. The absolute detection limits for the alkaloids was determined as fmol level. Moreover, the CE-MS was applied for the analyses of trypsin digestion of cytochrome C and small molecular organic anions. The emitter performed very stable with a lifetime of at least 180 h.
研究领域:
分析化学
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生物分析
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DOI
PubMed
高影响因子
CHIRALITY
·
2019
·Vol. 31
·期 4
·283-292
·
IF 1.927
Yingjie Li,Yimin Tang,Shili Qin,Xue Li,Qiang Dai,Lidi Gao
In order to use the enantioseparation capability of cationic cyclodextrin and to combine the advantages of capillary electrochromatography (CEC) with open-tubular (OT) column, in this study, a new OT-CEC, coated with cationic cyclodextrin (1-allylimidazolium-β-cyclodextrin [AI-β-CD]) as chiral stationary phase (CSP), was prepared and applied for enantioseparation. Synthesized AI-β-CD was characterized by infrared (IR) spectrometry and mass spectrometry (MS). The preparation conditions for the AI-β-CD-coated column were optimized with the orthogonal experiment design L 9 (3 4 ). The column prepared was characterized by scanning electron microscopy (SEM) and elemental analysis (EA). The results showed that the thickness of stationary phase in the inner surface of the AI-β-CD-coated columns was about 0.2 to 0.5 μm. The AI-β-CD content in stationary phase based on the EA was approximately 2.77 mmol·m −2 . The AI-β-CD-coated columns could separate all 14 chiral compounds (histidine, lysine, arginine, glutamate, aspartic acid, cysteine, serine, valine, isoleucine, phenylalanine, salbutamol, atenolol, ibuprofen, and napropamide) successfully in the study and exhibit excellent reproducibility and stability. We propose that the column, coated with AI-β-CD, has a great potential for enantioseparation in OT-CEC.
研究领域:
分析化学
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色谱技术
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DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2012
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IF 5.856
Qishu Qu,Chenhao Gu,Xiaoya Hu
Graphene oxide (GO) nanosheets were immobilized onto the capillary wall using 3-aminopropyldiethoxymethyl silane as coupling agent. Graphene coated column (G@column) was fabricated by hydrazine reduction of GO modified column. Scanning electron microscopy (SEM) images provided visible evidence of the GO grafted on the capillary wall. Energy dispersive X-ray spectrometry (EDS) indicated the high coverage of the GO on the capillary wall. The G@column exhibited a pH-dependent electroosmotic flow (EOF) from anode to cathode in the pH range of 3–9 while the graphene oxide coated column (GO@column) showed a constant EOF. Both GO@column and G@column were evaluated for open-tubular capillary electrochromatography (OT-CEC). The GO@column was also evaluated for open-tubular capillary liquid chromatography (OT-CLC). Good separation of the tested neutral analytes on the GO@column was achieved on the basis of a typical reversed-phase behavior. On the contrary, G@column showed poor separation performance because of the strong π–π stacking and hydrophobic interactions between graphene and polyaromatic hydrocarbons. The high coverage of GO improved the column phase ratio which makes the GO@column promising for OT-CLC separation. Five of the major known proteins including three glycoisoforms of ovalbumin in chicken egg white were identified in a single run on the GO@column with phosphate buffer (5 mM, pH 7.0) and an applied voltage of 20 kV. The run-to-run, day-to-day, and column-to-column reproducibilities are evaluated by calculating the relative standard deviations (RSDs) of the EOF in OT-CEC and retention time of naphthalene in OT-CLC, respectively. These RSD values were found to be less than 3%.
研究领域:
分析化学
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材料科学
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DOI
PubMed
高影响因子
ELECTROPHORESIS
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2014
·
IF 3.161
Ying Feng,Tingting Wang,Zhengjin Jiang,Bezhan Chankvetadze,Jacques Crommen
A series of eight chiral β-blocker drugs, acebutolol, atenolol, carazolol, carteolol, carvedilol, propranolol, sotalol, and talinolol, have been enantioseparated using two single-component anionic β-CD derivatives, namely heptakis (2,3-di- O -methyl-6-sulfo)-β-CD (HDMS-β-CD) and heptakis (2,3-di- O -acetyl-6-sulfo)-β-CD (HDAS-β-CD), in aqueous CE and NACE. The influence of the nature of substituents (methyl or acetyl) in positions 2 and 3 on the CD derivatives and of the electrophoretic medium (water or methanol) on the enantioselectivity and enantiomer affinity pattern (EAP) of these structurally related compounds was systematically studied. All eight β-blockers could be enantioseparated at least partially in the four CE systems, except sotalol with HDMS-β-CD in NACE. In general, lower affinity and enantioselectivity were obtained in the presence of HDMS-β-CD compared to HDAS-β-CD. Reversals of EAPs were observed for all compounds. EAPs toward these two CDs were found to be opposite to each other in NACE for all compounds except carvedilol and in aqueous CE for atenolol, carteolol, talinolol, and sotalol. It is particularly noteworthy that opposite EAPs were also observed using the same CD derivative when the aqueous BGE was replaced with the methanolic one: for carazolol, carvedilol, and propranolol in the presence of HDMS-β-CD and for acebutolol and carvedilol with HDAS-β-CD.
研究领域:
药物化学
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分析化学
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产品关联
DOI
PubMed
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2019
·Vol. 411
·期 6
·1193-1202
·
IF 3.286
Sun Xiaodong,Guo Jie,Yu Tao,Du Yingxiang,Feng Zijie,Zhao Shiyuan,Huang Zhifeng,Liu Jie
Magnetic microparticles (MMPs) have been extensively studied and aroused considerable interest in separation science owing to their superior characteristics. In this paper, a novel coated capillary with carboxymethyl-β-cyclodextrin-functionalized magnetic microparticles (CD-MMPs) as stationary phase was constructed and then applied to establish an open-tubular capillary electrochromatography enantioseparation system. The preparation of the CD-MMP-coated open-tubular column was very convenient because the coating of the magnetic microparticles onto the capillary column could be easily manipulated by an external magnetic field. The preparation conditions of the coated capillary such as magnetic field intensity and coating time are discussed in detail. The new constructed CD-MMP capillary system was applied to separate enantiomers of several racemic drugs. Compared to the uncoated capillary system, obviously preferable separations of tested enantiomers were obtained. Several important parameters affecting the enantioseparation, such as CM-β-CD concentration, running buffer pH, organic solvent, and applied voltage, were systematically optimized. Furthermore, satisfactory repeatability and chemical stability of this new CD-MMP capillary system were achieved in the experiment.
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研究领域:
分析化学
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分离科学
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药物分析
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DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2018
·
IF 3.716
Qing Liu,Kevin Yan,Qiaomei Chen,Soumia Cheddah,Lin Shen,Han Xiao,Yan Wang,Chao Yan
Capillary column packed with silica colloidal crystals (SCC) exhibits great efficiency in liquid chromatography because of its highly-ordered structure and extremely narrow channels (about hundred nanometer in diameter) between the particles. However, problems arise due to the extremely high back-pressure created with its dense packings. It is also a challenge to prepare a stable SCC column with an appropriate length for chromatographic separation on a commercial instrument. We have synthesized monodispersed, sub-micron SiO 2 particles bonded with C18 functionality and fabricated SCC capillary columns up to 100 mm in length. The packing materials in the column displayed Bragg diffraction with blueish color under irradiation with white light, indicating the formation of SCC. The column performance was evaluated using pressurized capillary electrochromatography (pCEC) and column efficiencies of more than a hundred thousand plates per column (plate height < 1 μm) were achieved using peptide as a sample. The run-to-run reproducibility expressed with RSD in terms of retention time and peak area for aromatic compounds were less than 0.076% and 1.96%, respectively. These results demonstrate that the combination of pCEC and SCC columns may provide an innovative analytical technique with extraordinary efficiency, resolution and speed for the separation of complex samples.
研究领域:
分析化学
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色谱技术
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DOI
PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY A
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2019
·
IF 3.858
Wei Zhou,Yikun Liu,Xiaoyan Liao,Zilin Chen
Nonaqueous capillary electrophoresis (CE) and organic-aqueous CE using high content of organic solvents are common techniques in capillary electrophoresis-mass spectrometry (CE-MS) due to various advantages. However, the long-term stability of commonly used polyimide coated fused silica capillary remains a major problem that polyimide coating is prone to swelling in organic solvents and aminolysis in alkaline buffer, which cause serious problems like irregular electrospray, current drop or clogging event. In this work, robust PEEK capillary was used as separation capillary for tolerance to high content of organic solvents in CE-MS system. It is interesting that the high mechanical and chemical stability of PEEK capillary ensured stable CE separation and electrospray when used in CE-MS. All quantitative experiments were accomplished by single PEEK capillary. In addition, the using of organic solvents as running buffer reduced adsorption of hydrophobic compounds on PEEK capillary wall and improved the symmetry of peak shape. The PEEK-based CE-MS method showed good separation performance in analysis of several groups of active alkaloids in traditional Chinese medicines and was applied for quantitative analysis of peimine and peiminine in Bulbus Fritillariae thunbergii herb with high sensitivity. Based on the advantages like simple pretreatment, easy to cut, stable and good separation performance of PEEK column in CE-MS, this study provides an effective way for improving the stability and employment of high content of organic solvents in CE-MS analysis.
研究领域:
分析化学
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中药学
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DOI
PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2021
·
IF 4.759
Yuanyuan Fu,Zhentao Li,Qiaoyan Li,Changjun Hu,Yikun Liu,Wenqi Sun,Zilin Chen
Covalent organic frameworks (COFs), considered as a series of newly emerging porous organic materials, have been widely utilized in separation fields. Herein, a novel COF (TFPB-BD) was first employed as stationary phase for high-efficiency capillary electrochromatographic separation. Benzidine (BD) and 1,3,5-Tris-(4-formylphenyl)benzene (TFPB) were selected as organic linkers and then introduced into the aldehyde group modified capillary for the in situ growth of TFPB-BD onto the capillary inner wall at room temperature. The morphology and formation of TFPB coated capillary column were confirmed by a variety of tools including Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). It's interesting that the TFPB globular crystals with nanoscale were uniformly and densely modified on the capillary inner surface. Hence, the prepared column exhibited prominent separation performance for the test analytes including alkylbenzenes, chlorobenzenes and phenolic compounds with high efficiency and high resolution. The maximum column efficiency can reach about 1.8 × 10 5 plates•m −1 . Additionally, the high resolutions of anilines, amino acids and parabens were also achieved on the TFPB modified capillary. The precisions (RSDs) of the retention times of alkylbenzenes of intra-day runs ( n = 3), inter-day runs ( n = 3) and parallel columns ( n = 3) were all less than 2.83%. This innovative COF-based stationary phase gives great promise for the chromatographic separation field.
研究领域:
分析化学
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材料科学
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DOI
PubMed
高影响因子
MICROCHIMICA ACTA
·
2021
·Vol. 188
·期 11
·1-7
·
IF 5.833
Wang Tingting,Yang Li,Cheng Yuhuan,Zhang Yulian,Ye Jiannong,Chu Qingcui,Cheng Guifang
A novel kind of chiral open-tubular (OT) column was established with homochiral zeolitic imidazolate framework-8 nanomaterials using L-histidine as the chiral carbon center (L-His-ZIF-8). The morphologies of L-His-ZIF-8 nanoparticles and chiral OT column were characterized by scanning electron microscopy. The effects of L-His-ZIF-8 concentrations, pH values, and concentrations of the running buffer on the resolution of the selected chiral compounds were investigated based on miniaturized capillary electrochromatography with amperometric detection system (mini-CEC-AD), respectively. The separation performances of the prepared L-His-ZIF-8@OT chiral columns were explored under the optimal conditions, and the RSDs of run-to-run, day-to-day, and column-to-column reproducibility were less than 6.7% using salbutamol raceme as the model enantiomers. The prepared chiral OT columns have been successfully applied to the enantioseparation of one pair of amino acid enantiomers, two pairs of racemic drugs, and three pairs of neurotransmitter enantiomers. Under the optimum conditions, the prepared OT columns were applied to real-world sample analysis of salbutamol aerosol. The limits of detection of salbutamol raceme were 0.90 μg·mL −1 (S/N = 3), and the recovery was 80.4–82.7%. The assay results indicated that this kind of chiral OT column modified with homochiral L-His-ZIF-8 possesses good reproducibility and stability. This developed mini-OT-CEC-AD system has some attractive characteristics of sensitivity and low cost, providing a potential way for the separation of chiral compounds. Graphic Abstract
研究领域:
分析化学
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材料科学
·
生物医学
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DOI
PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
·
2018
·
IF 2.441
Yueping Zhu,Zhenqing Li,Ping Wang,Lisong Shen,Dawei Zhang,Yoshinori Yamaguchi
Capillary electrophoresis (CE) is an effective tool for protein separation and analysis. Compared with capillary gel electrophoresis (CGE), non-gel sieving capillary electrophoresis (NGSCE) processes the superiority on operation, repeatability and automaticity. Herein, we investigated the effect of polymer molecular weight and concentration, electric field strength, and the effective length of the capillary on the separation performance of proteins, and find that (1) polymer with high molecular weight and concentration favors the separation of proteins, although concentrated polymer hinders its injection into the channel of the capillary due to its high viscosity. (2) The resolution between the adjacent proteins decreases with the increase of electric field strength. (3) When the effective length of the capillary is long, the separation performance improves at the cost of separation time. (4) 1.4% (w/v) hydroxyethyl cellulose (HEC), 100 V/cm voltage and 12 cm effective length offers the best separation for the proteins with molecular weight from 14,400 Da to 97,400 Da. Finally, we employed the optimal electrophoretic conditions to resolve Lysozyme , Ovalbumin , BSA and their mixtures, and found that they were baseline resolved within 15 min.
研究领域:
分析化学
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生物化学
·
电泳技术
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DOI
PubMed
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2021
·
IF 5.876
Jiaxin Huang,Yatian Zhang,Chunxian Tao,Shanni Li,Qingxiang You,Dawei Zhang,Zhenqing Li,Yoshinori Yamaguchi
Background Capillary electrophoresis (CE) is an effective method for protein analysis. Although previous researchers have proved that the separation performance of large DNA molecules was improved by pulsed field capillary electrophoresis (PFCE), there is lack of research about proteins separation by PFCE. Methods Herein, we systematically investigated the separation performance of proteins sized from 44 kDa to 200 kDa under square wave and inversion electric field, respectively. Findings Results showed that for pulsed electric field with same forward and backward time duration, there was a resonance frequency for protein molecule re-orientation and applied frequency, and the apparent mobility ( μ ) was the lowest at the resonance frequency. μ was positively correlated to modulation depth ( M ) if M was below 200%, while μ was negatively correlated to M if M was higher than 200%. For CE with same forward and backward voltage, it demonstrated that μ dropped as M went up, but the separation performance for proteins with high molecular mass improved. Through PFCE, albumin and α- globulins in human serum were also resolved within 7 min. Such a work may shed new light on the analysis of proteins by PFCE.
研究领域:
分析化学
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生物技术
·
生物化学
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产品关联
DOI
高影响因子
MICROCHEMICAL JOURNAL
·
2024
·
IF 4.9
Xin-Ran Ma,Yi-Wen Wu,Qian-Xue Shen,Yan-Hua Jiao,Jun Cao,Li-Hong Ye
One-step admicelle to cyclodextrin sweeping (ACDS) method in capillary electrophoresis (CE) has been developed for the separation and preconcentration of toxic aristolochic acids (AAs) by applying cetyltrimethylammonium chloride (CTAC) between the critical micelle concentration and critical surface aggregation concentration. The analytes were captured into the CTAC admicelles, after the more stable inclusion complexes were formed, the release and preconcentration of the analytes could be realized. The CE enrichment parameters, such as the types of cationic surfactants and cyclodextrins (CDs), the concentration of cationic surfactants, disodium tetraborate decahydrate (borax) and CDs, the volume ratio of acetonitrile (ACN) in background electrolyte (BGE) and the sample injection time were optimized systemically. The optimal BGE was composed of 20 mM borax, 10 mM γ-CD and 10 % (v/v) ACN, the sample matrix consisted of 0.2 mM CTAC, 20 mM borax and five analytes. The limit of detection of this method was 3–6 ng/mL, and good linearity values (R 2 ) were obtained for five AAs in the range of 0.997–0.999. Applying optimized conditions, the enrichment efficiencies of five AAs were enhanced with the sensitivity enrichment factors of 30–68. The sweeping approach was successfully applied to the determination of A, B, Ⅶ a , C and D in Aristolochia and Asarum samples, which could provide a potential in the enrichment of the other toxic compounds.
研究领域:
分析化学
·
毒理学
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DOI
高影响因子
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