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Guo Z, Chen Y, Wang S, Pang J, Liu Z. Dendritic Mesoporous Silica Nanospheres: Toward the Ultimate Minimum Particle Size for Ultraefficient Liquid Chromatographic Separation. ACS APPLIED MATERIALS & INTERFACES 2021; 13:22970-22977. [PMID: 33956437 DOI: 10.1021/acsami.1c03985] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Use of smaller particle size of packing materials in liquid chromatography leads to faster separation and higher efficiency. This basic law has driven the evolution of packing materials for several generations. However, the use of nanoscale packing materials has been severely hampered by extremely high back pressure. Here, we report a new possibility of solving this issue via introducing novel nanomaterials with highly favorable structures. n-Octyl-modified monodispersed dendritic mesoporous silica nanospheres (DMSNs) with an unprecedentedly small diameter (ca. 170 nm) and appropriate pore size (5.6 nm) were controllably synthesized and demonstrated to be a practically applicable packing material offering ultrahigh efficiency. The center-radial centrosymmetric mesopore channels significantly improved the permeability of packed capillaries, enabling column packing and capillary electrochromatographic separation on regular instruments. Due to the unique morphology, very tiny particle size, and highly uniform packing, the packed column exhibited ultrahigh efficiency up to 3 500 000 plates/m. Powerful separation capability was demonstrated with glycan profiling of cancerous and normal cells, which revealed that cancerous cells exhibited characteristic N-glycans. Because DMSNs with tunable particle size and mesopores can be controllably prepared, DMSNs hold great potential to be a new record toward the ultimate generation of packing materials for ultraefficient liquid chromatographic separation.
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Affiliation(s)
- Zhanchen Guo
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China
| | - Yang Chen
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China
| | - Shuangshou Wang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China
| | - Jilei Pang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China
| | - Zhen Liu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China
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Tetrabutylammonium bromide assisted preparation of monodispersed submicrometer silica particles. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.126171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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3
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Adam V, Vaculovicova M. CE and nanomaterials - Part II: Nanomaterials in CE. Electrophoresis 2017; 38:2405-2430. [DOI: 10.1002/elps.201700098] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 07/04/2017] [Accepted: 07/05/2017] [Indexed: 12/23/2022]
Affiliation(s)
- Vojtech Adam
- Department of Chemistry and Biochemistry; Mendel University in Brno; Brno Czech Republic
- Central European Institute of Technology; Brno University of Technology; Brno Czech Republic
| | - Marketa Vaculovicova
- Department of Chemistry and Biochemistry; Mendel University in Brno; Brno Czech Republic
- Central European Institute of Technology; Brno University of Technology; Brno Czech Republic
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4
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Fanali S. An overview to nano-scale analytical techniques: Nano-liquid chromatography and capillary electrochromatography. Electrophoresis 2017; 38:1822-1829. [PMID: 28256745 DOI: 10.1002/elps.201600573] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 02/17/2017] [Accepted: 02/21/2017] [Indexed: 01/04/2023]
Abstract
Nano-liquid chromatography (nano-LC) and CEC are microfluidic techniques mainly used for analytical purposes. They have been applied to the separation and analysis of a large number of compounds, e.g., peptides, proteins, drugs, enantiomers, antibiotics, pesticides, nutraceutical, etc. Analytes separation is carried out into capillaries containing selected stationary phase. The mobile phase is moved either by a pump (nano-LC) or by an EOF, respectively. The two tools can offer some advantages over conventional techniques, e.g., high selectivity, separation efficiency, resolution, short analysis time and consumption of low volumes of mobile phase. Flow rates in the range 50-800 nL/min are usually applied. The low flow rate reduces the chromatographic dilution increasing the mass sensitivity. Special attention must be paid in avoiding peak dispersion selecting the appropriate detector, injector and tube connection. Finally due to the low flow rate these microfluidic techniques can be easily coupled with mass spectrometry.
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Affiliation(s)
- Salvatore Fanali
- Institute of Chemical Methodologies, Italian National Research Council, Monterotondo, Italy
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Zhang Y, Wang W, Xiao X, Jia L. Separation of monoclonal antibody charge state variants by open tubular capillary electrochromatography with immobilised protein as stationary phase. J Chromatogr A 2016; 1466:180-8. [DOI: 10.1016/j.chroma.2016.09.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 09/01/2016] [Accepted: 09/02/2016] [Indexed: 11/25/2022]
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D'Orazio G, Asensio-Ramos M, Fanali C, Hernández-Borges J, Fanali S. Capillary electrochromatography in food analysis. Trends Analyt Chem 2016. [DOI: 10.1016/j.trac.2016.06.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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7
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Ali I, Suhail M, Lone MN, Alothman ZA, Alwarthan A. Chiral resolution of multichiral center racemates by different modalities of chromatography. J LIQ CHROMATOGR R T 2016. [DOI: 10.1080/10826076.2016.1152582] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Imran Ali
- Department of Chemistry, Jamia Millia Islamia Central University, New Delhi, India
| | - Mohd Suhail
- Department of Chemistry, Jamia Millia Islamia Central University, New Delhi, India
| | - Mohammad Nadeem Lone
- Department of Chemistry, Jamia Millia Islamia Central University, New Delhi, India
| | - Zeid A. Alothman
- Department of Chemistry, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
| | - Abdulrahman Alwarthan
- Department of Chemistry, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
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Sun B, Qi L, Li Y, Qiao J, Wang M. Separation of aromatic amines by an open-tubular capillary electrochromatography method. J Sep Sci 2013; 36:3629-34. [DOI: 10.1002/jssc.201300822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 07/28/2013] [Accepted: 08/17/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Bingbing Sun
- College of Food Sciences and Engineering; Shandong Agricultural University; Tai'an Shandong P. R. China
- Beijing National Laboratory for Molecular Sciences; Key Lab of Analytical Chemistry for Living Biosystems; Institute of Chemistry, Chinese Academy of Sciences; Beijing P. R. China
| | - Li Qi
- Beijing National Laboratory for Molecular Sciences; Key Lab of Analytical Chemistry for Living Biosystems; Institute of Chemistry, Chinese Academy of Sciences; Beijing P. R. China
| | - Yaping Li
- Beijing National Laboratory for Molecular Sciences; Key Lab of Analytical Chemistry for Living Biosystems; Institute of Chemistry, Chinese Academy of Sciences; Beijing P. R. China
- Graduate School; University of Chinese Academy of Sciences; Beijing P. R. China
| | - Juan Qiao
- Beijing National Laboratory for Molecular Sciences; Key Lab of Analytical Chemistry for Living Biosystems; Institute of Chemistry, Chinese Academy of Sciences; Beijing P. R. China
| | - Minglin Wang
- College of Food Sciences and Engineering; Shandong Agricultural University; Tai'an Shandong P. R. China
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Bou Khalil M, Hou W, Zhou H, Elisma F, Swayne LA, Blanchard AP, Yao Z, Bennett SAL, Figeys D. Lipidomics era: accomplishments and challenges. MASS SPECTROMETRY REVIEWS 2010; 29:877-929. [PMID: 20931646 DOI: 10.1002/mas.20294] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Lipid mediators participate in signal transduction pathways, proliferation, apoptosis, and membrane trafficking in the cell. Lipids are highly complex and diverse owing to the various combinations of polar headgroups, fatty acyl chains, and backbone structures. This structural diversity continues to pose a challenge for lipid analysis. Here we review the current state of the art in lipidomics research and discuss the challenges facing this field. The latest technological developments in mass spectrometry, the role of bioinformatics, and the applications of lipidomics in lipid metabolism and cellular physiology and pathology are also discussed.
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Affiliation(s)
- Maroun Bou Khalil
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, Canada K1H 8M5
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10
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Chiral separation by capillary electromigration techniques. J Chromatogr A 2008; 1204:140-56. [DOI: 10.1016/j.chroma.2008.07.071] [Citation(s) in RCA: 208] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 06/27/2008] [Accepted: 07/08/2008] [Indexed: 11/19/2022]
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Chen XJ, Ji H, Wang YT, Li SP. Simultaneous determination of seven flavonoids in Epimedium using pressurized liquid extraction and capillary electrochromatography. J Sep Sci 2008; 31:881-7. [PMID: 18293424 DOI: 10.1002/jssc.200700615] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Herba Epimedii (known as Yinyanghuo in China) is one of the commonly used Chinese medicines. Flavonoids are considered as its active components. In this study, a CEC method was developed for the simultaneous determination of seven flavonoids, including hexandraside E, kaempferol-3-O-rhamnoside, hexandraside F, icariin, epimedin A, B, and C, in Epimedium using baicalein as internal standard (IS). The influence of relevant parameters such as buffer concentration, pH, and proportion of ACN was investigated and optimized. Baseline separation was obtained using a Hypersil C18 capillary (3 microm, 100 microm/25 cm) with a mixture of 20 mM phosphate buffer (pH 4.0)/ACN (70:30 v/v) as mobile phase running at 30 kV and 25 degrees C in 20 min. All calibration curves showed good linearity (r2 >0.9992) within test ranges. The LOD and LOQ were lower than 8.6 and 42.8 microg/mL, respectively. The RSDs of intra- and interday for relative peak areas of seven analytes were less than 3.1 and 4.4%, and the recoveries were 95.2-103.3%. Samples of different Epimedium species were analyzed using the validated method, which is useful for quality control of Epimedium and its medical preparations.
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Affiliation(s)
- Xiao-jia Chen
- Institute of Chinese Medical Sciences, University of Macau, Macao SAR, China
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Carbonnier B, Guerrouache M, Denoyel R, Millot MC. CEC separation of aromatic compounds and proteins on hexylamine-functionalizedN-acryloxysuccinimide monoliths. J Sep Sci 2007; 30:3000-10. [DOI: 10.1002/jssc.200700384] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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13
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Lü H, Wang J, Wang X, Wu X, Lin X, Xie Z. Single-step preparation and characterization of polymeric monolith for pressurized capillary electrochromatography of typical homologs. J Sep Sci 2007; 30:2993-9. [PMID: 17880031 DOI: 10.1002/jssc.200700220] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A monolithic stationary phase was prepared in a single step by in situ copolymerization of iso-butyl methacrylate (IBMA), ethylene dimethacrylate (EDMA), and N,N-dimethylallylamine (DMAA) in a binary porogenic solvent consisting of N,N-dimethylformamide (DMF) and 1,4-butanediol. As the frame structures of monoliths, the amino groups are linked to support the EOF necessary for driving the mobile phase through the monolithic capillary, while the hydrophobic groups are introduced to provide the nonpolar sites for the chromatographic retention. To evaluate the column performance, separations of typical kinds of neutral or charged homologs, such as alkylbenzenes, phenols (including isomeric compounds of hydroquinone, resorcin, and catechol), and anilines (including isomeric compounds of o-phenylenediamine and 1,4-phenylenediamine), were performed, respectively on the prepared column under the mode of pressurized pCEC. Effects of the buffer pH and the mobile phase composition on the linear velocity of mobile phase and the retention factors of these compounds were investigated. It was found that the retention mechanism of charged solutes could be attributed to a mixed mode of hydrophobic interaction and electrophoresis, while an RP chromatographic behavior on the monolithic stationary phases was exhibited for neutral solutes. Especially, basic compounds such as anilines were well separated on the monolithic columns in the "counterdirectional mode," which effectively eliminated the electrostatic adsorption of basic analytes on the charged surface of the stationary phases.
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Affiliation(s)
- Haixia Lü
- College of Materials Science and Engineering, Fuzhou University, Fuzhou, Fujian, China
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Abstract
In this review, an overview of CEC and EKC methods with their developments are summarized for different natural compounds. It is divided into three main parts. The first part elaborates the separation of lipophilic compounds without any charged groups. The second part constitutes CEC and EKC of lipophilic compounds containing ionizable functional groups whereas the third part contains hydrophilic compounds. Packed, monolithic, coated, or raw fused-silica (FS) capillaries are among the choice for stationary phases. Applications of these phases on the above-mentioned three classes of compounds, coupled with different detection methods, e.g. MS or LIF, are explored and their advantages and disadvantages are discussed.
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Affiliation(s)
- Heimo Scherz
- Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens-University, Innsbruck, Austria
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15
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Mistry K, Grinberg N. Separation of Peptides and Proteins by Capillary Electrochromatography. J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-120030601] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Kavita Mistry
- a Analytical Research , Merck & Co., Inc. , RY818‐C208, P.O. Box 2000, Rahway , New Jersey , 07065 , USA
| | - Nelu Grinberg
- a Analytical Research , Merck & Co., Inc. , RY818‐C208, P.O. Box 2000, Rahway , New Jersey , 07065 , USA
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Musenga A, Mandrioli R, Ferranti A, D'Orazio G, Fanali S, Raggi MA. Analysis of aromatic and terpenic constituents of pepper extracts by capillary electrochromatography. J Sep Sci 2007; 30:612-9. [PMID: 17444231 DOI: 10.1002/jssc.200600456] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
An original method based on CEC has been developed for the determination of aromatic and terpenic compounds in extracts of spices obtained from Piper nigrum. The method is based on the use of a fused silica capillary (effective length: 23.5 cm, internal diameter: 100 microm) packed with a C18 sorbent (packing length: 23 cm, particle size: 5 microm). The mobile phase is a 50 mM, pH 6.0 ammonium acetate/ACN (10:90 v/v) mixture. Applying a 30 kV voltage, the following 11 compounds were separated and analysed: terpinen-4-ol, caryophyllene oxide, limonene, alpha-pinene, 3-carene, beta-pinene, alpha-humulene, beta-caryophyllene, alpha-phellandrene, eugenol and piperine. Compound determination is carried out using a diode-array detector set at 265 and 338 nm for alpha-phellandrene and piperine, respectively, and at 210 nm (reference subtraction at 282 nm) for all the other analytes. The optimised method has been validated with good results in terms of linearity, limits of quantitation, detection and precision. The CEC method was successfully applied to the analysis of essential oils and methanolic extracts of 'black', 'white' and 'green' pepper.
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Affiliation(s)
- Alessandro Musenga
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Alma Mater Studiorum - University of Bologna, Bologna, Italy
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17
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Rocco A, Aturki Z, D'Orazio G, Fanali S, Solínová V, Hlavácek J, Kasicka V. CEC separation of insect oostatic peptides using a strong-cation-exchange stationary phase. Electrophoresis 2007; 28:1689-95. [PMID: 17476717 DOI: 10.1002/elps.200600452] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The separation of several insect oostatic peptides (IOPs) was achieved by using CEC with a strong-cation-exchange (SCX) stationary phase in the fused-silica capillary column of 75 microm id. The effect of organic modifier, ionic strength, buffer pH, applied voltage, and temperature on peptides' resolution was evaluated. Baseline separation of the studied IOPs was achieved using a mobile phase containing 100 mM pH 2.3 sodium phosphate buffer/water/ACN (10:20:70 v/v/v). In order to reduce the analysis time, experiments were performed in the short side mode where the stationary phase was packed for 7 cm only. The selection of the experimental parameters strongly influenced the retention time, resolution, and retention factor. An acidic pH was selected in order to positively charge the analyzed peptides, the pI's of which are about 3 in water buffer solutions. A good selectivity and resolution was achieved at pH <2.8; at higher pH the three parameters decreased due to reduced or even zero charge of peptides. The increase in the ionic strength of the buffer present in the mobile phase caused a decrease in retention factor for all the studied compounds due to the decreased interaction between analytes and stationary phase. Raising the ACN concentration in the mobile phase in the range 40-80% v/v caused an increase in both retention factor, retention time, and resolution due to the hydrophilic interactions of IOPs with free silanols and sulfonic groups of the stationary phase.
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Affiliation(s)
- Anna Rocco
- Institute of Chemical Methodologies, National Council of Research, Monterotondo Scalo, Rome, Italy
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18
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Yang FQ, Li S, Li P, Wang YT. Optimization of CEC for simultaneous determination of eleven nucleosides and nucleobases inCordyceps using central composite design. Electrophoresis 2007; 28:1681-8. [PMID: 17464961 DOI: 10.1002/elps.200600416] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A CEC method is described for the simultaneous determination of 11 nucleosides and nucleobases including cytosine, uracil, uridine, hypoxanthine, 2'-deoxyuridine, inosine, guanosine, thymidine, adenine, adenosine, and cordycepin in Cordyceps using 5-chlorocytosine arabinoside as internal standard (IS). Chemometric optimization based on central composite design was employed to find the optimum conditions. The factors for optimization were defined as three parameters: voltage, pH, and concentration of ACN as organic modifier. The resolution (R(s)) between inosine and guanosine, as well as the entire run time were employed to evaluate the response function. A running buffer composed of 4 mM ammonium acetate and 2 mM triethylamine (TEA) adjusted to pH 5.3 using acetic acid, and containing 3% ACN as modifier, with gradient voltage (0-4 min: 20 kV, 4-12 min: linear gradient from 20 to 30 kV; 12-16 min: 30 kV) were found to be the optimum conditions for the separation. Separation of the 11 investigated compounds and 5-chlorocytosine arabinoside was achieved within 16 min. The contents of the 11 compounds in natural and cultured Cordyceps sinensis, and cultured Cordyceps militaris were also compared. The result showed that CEC is an efficient method for analysis of nucleosides and nucleobases in Cordyceps, which is helpful to control the quality of this valued traditional Chinese medicine.
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Affiliation(s)
- Feng Q Yang
- Institute of Chinese Medical Sciences, University of Macau, Taipa, Macau, China
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Li P, Li SP, Yang FQ, Wang YT. Simultaneous determination of four tanshinones insalvia miltiorrhiza by pressurized liquid extraction and capillary electrochromatography. J Sep Sci 2007; 30:900-5. [PMID: 17536735 DOI: 10.1002/jssc.200600368] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A pressurized liquid extraction (PLE) and CEC were developed for the simultaneous determination of four tanshinones (dihydrotanshinone I, cryptotanshinone, tanshinone I, and tanshinone IIA) in Salvia miltiorrhiza. High extraction efficiency (>98.5%) was achieved under the optimum PLE conditions. A good separation was obtained by using a Hypersil C18 capillary (3 microm, 100 microm/25 cm) with a mixture of 30 mM Tris-HCl (pH 8.5)-ACN (1:3, v/v) as BGE solution running at 20 kV and 20 degrees C within 12 min. All the calibration curves showed good linearity (r2 >0.9958) within test ranges. The developed method showed good repeatability for the quantification of four investigated components in S. miltiorrhiza with intra- and interday variations of less than 4.4 and 6.8%, respectively. The validated method was successfully applied to quantify four tanshinones in S. miltiorrhiza, which is helpful to control the quality of S. miltiorrhiza.
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Affiliation(s)
- Peng Li
- Institute of Chinese Medical Sciences, University of Macau, Taipa, Macau, China
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20
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Debowski JK. SELECTED APPLICATIONS OF CAPILLARY ELECTROCHROMATOGRAPHY IN THE PHARMACEUTICAL INDUSTRY: TO BUY OR NOT TO BUY? J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-120013988] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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21
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Okamoto Y, Ikawa Y, Kitagawa F, Otsuka K. Preparation of fritless capillary using avidin immobilized magnetic particles for electrochromatographic chiral separation. J Chromatogr A 2007; 1143:264-9. [PMID: 17240386 DOI: 10.1016/j.chroma.2007.01.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Revised: 12/26/2006] [Accepted: 01/02/2007] [Indexed: 10/23/2022]
Abstract
In capillary electrochromatography (CEC), magnetic particles (MPs) were packed in a fused silica capillary by using the magnetic field to be retained without frits. For a chiral CEC separation, avidin was immobilized onto the surface of the MPs (AVI-MPs) as a stationary phase by using the physical adsorption technique. The injected AVI-MPs into the capillary were stably captured with the magnet (surface magnetic flux density, 250 mT) under the separation voltage of 10 kV (190 V/cm). By employing the fritless AVI-MPs packed capillary, the chiral separation of ketoprofen was successfully attained with the packing length of only 5 cm. Effects of the modification condition of avidin, pH of background solution, and the packing length on the enantioseparation were also investigated. Under the optimal condition, furthermore, the repeatability for the retention time of ketoprofen was better than 1.5% in the relative standard deviation and the capillary-to-capillary reproducibility was also acceptable in the prepared fritless capillaries.
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Affiliation(s)
- Yukihiro Okamoto
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
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Zhang K, Yan C, Zhang Z, Wang Q, Gao R. Mixed Mode of Hydrophilic and Ionic Interaction Pressurized Capillary Electrochromatography for Separation of Basic Compounds. J LIQ CHROMATOGR R T 2006. [DOI: 10.1081/jlc-120022397] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Kai Zhang
- a State Key Laboratory of Elemento‐Organic Chemistry , Nankai University , Tianjin , 300071 , P.R. China
| | - Chao Yan
- b Unimicro Technologies, Inc. , Pleasanton , California , USA
| | - Zhichao Zhang
- a State Key Laboratory of Elemento‐Organic Chemistry , Nankai University , Tianjin , 300071 , P.R. China
| | - Qinsun Wang
- a State Key Laboratory of Elemento‐Organic Chemistry , Nankai University , Tianjin , 300071 , P.R. China
| | - Ruyu Gao
- a State Key Laboratory of Elemento‐Organic Chemistry , Nankai University , Tianjin , 300071 , P.R. China
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Lin B, Shi ZG, Zhang HJ, Ng SC, Feng YQ. Perphenylcarbamoylated β-cyclodextrin bonded-silica particles as chiral stationary phase for enantioseparation by pressure-assisted capillary electrochromatography. Electrophoresis 2006; 27:3057-65. [PMID: 16800030 DOI: 10.1002/elps.200500906] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Perphenylcarbamoylated beta-cyclodextrin bonded-silica particles (5 microm) were packed into 75-mum fused-silica capillaries, and used for the enantiomer separation of neutral and basic solutes by pressure-assisted capillary electrochromatography. Triethylammonium acetate and phosphate buffer were employed as the BGEs. A cathodic EOF was observed with these two BGEs. Seven chiral analytes were successfully resolved into their enantiomers under optimized conditions, and five of them could be baseline-separated within 12 min due to their high electrophoretic mobility. Better results were achieved with phosphate buffer as the BGE. The effects of organic content and pH on the enantioseparation were also investigated.
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Affiliation(s)
- Bo Lin
- Department of Chemistry, Wuhan University, Wuhan 430072, P. R. China
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Gübitz G, Schmid MG. Chiral separation principles in chromatographic and electromigration techniques. Mol Biotechnol 2006; 32:159-80. [PMID: 16444017 DOI: 10.1385/mb:32:2:159] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Almost half of the drugs in use today are chiral. It is well established that the pharmacological activity is mostly restricted to one of the enantiomers (eutomer). There can be qualitative and quantitative differences in the activity of the enantiomers. In many cases, the inactive enantiomer (distomer) shows unwanted side effects or even toxic effects. Even if the side effects are not that drastic, the distomer has to be metabolized and this represents an unnecessary burden for the organism. Therefore, the development of methods for the separation of enantiomers, both on analytical and preparative scale, has become increasingly important. Chromatographic techniques such as thin layer chromatography (TLC), gas chromatography (GC), supercritical fluid chromatography (SFC), and above all high-performance liquid chromatography (HPLC) have been used for enantiomer separation for about two decades. More recently, electromigration techniques, such as capillary electrophoresis and capillary electrochromatography, have been shown to be powerful alternatives to chromatographic methods. This review gives a short overview of different chiral separation principles and their application. Several new developments are discussed.
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Affiliation(s)
- Gerald Gübitz
- Institute of Pharmaceutical Sciences, Department of Pharmaceutical Chemistry, Karl-Franzens University, Universitätsplatz 1, A-8010 Graz, Austria
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25
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Tian R, Sun J, Zhang H, Ye M, Xie C, Dong J, Hu J, Ma D, Bao X, Zou H. Large-pore mesoporous SBA-15 silica particles with submicrometer size as stationary phases for high-speed CEC separation. Electrophoresis 2006; 27:742-8. [PMID: 16421943 DOI: 10.1002/elps.200500630] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A new mesoporous sphere-like SBA-15 silica was synthesized and evaluated in terms of its suitability as stationary phases for CEC. The unique and attractive properties of the silica particle are its submicrometer particle size of 400 nm and highly ordered cylindrical mesopores with uniform pore size of 12 nm running along the same direction. The bare silica particles with submicrometer size have been successfully employed for the normal-phase electrochromatographic separation of polar compounds with high efficiency (e.g., 210,000 for thiourea), which is matched well with its submicrometer particle size. The Van Deemeter plot showed the hindrance to mass transfer because of the existence of pore structure. The lowest plate height of 2.0 microm was obtained at the linear velocity of 1.1 mm/s. On the other hand, because of the relatively high linear velocity (e.g., 4.0 mm/s) can be generated, high-speed separation of neutral compounds, anilines, and basic pharmaceuticals in CEC with C18-modified SBA-15 silica as stationary phases was achieved within 36, 60, and 34 s, respectively.
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Affiliation(s)
- Ruijun Tian
- National Chromatographic R&A Center, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, PR China
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26
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Abstract
In this review, an updated view of the different strategies used up to now to enhance the sensitivity of detection in chiral analysis by CE will be provided to the readers. With this aim, it will include a brief description of the fundamentals and most of the recent applications performed in sensitive chiral analysis by CE using offline and online sample treatment techniques (SPE, liquid-liquid extraction, microdialysis, etc.), on-column preconcentration techniques based on electrophoretic principles (ITP, stacking, and sweeping), and alternative detection systems (spectroscopic, spectrometric, and electrochemical) to the widely used UV-Vis absorption detection.
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Affiliation(s)
- Carmen García-Ruiz
- Departamento de Química Analítica, Facultad de Química, Universidad de Alcalá, Alcalá de Henares, Madrid, Spain
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Alexander C, Andersson HS, Andersson LI, Ansell RJ, Kirsch N, Nicholls IA, O'Mahony J, Whitcombe MJ. Molecular imprinting science and technology: a survey of the literature for the years up to and including 2003. J Mol Recognit 2006; 19:106-80. [PMID: 16395662 DOI: 10.1002/jmr.760] [Citation(s) in RCA: 776] [Impact Index Per Article: 43.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Over 1450 references to original papers, reviews and monographs have herein been collected to document the development of molecular imprinting science and technology from the serendipitous discovery of Polyakov in 1931 to recent attempts to implement and understand the principles underlying the technique and its use in a range of application areas. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by papers dealing with fundamental aspects of molecular imprinting and the development of novel polymer formats. Thereafter, literature describing attempts to apply these polymeric materials to a range of application areas is presented.
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Affiliation(s)
- Cameron Alexander
- The School of Pharmacy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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28
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Abstract
In order to investigate the amino acids (AAs) in plant cells, we explore an avenue for intracellular derivatization with FITC. In this method, FITC was used to mark AAs in living protoplasts derived from embryogenic calli of common wheat (Triticum aestivum L. c.v. Jinan 177) mediated by PEG. After FITC-derivatization, the AAs in the lysate were determined by CE. The result reveals that this PEG method can be used to transfer FITC into plant cells efficiently, which provides a good method for AA analysis in plant cells.
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Affiliation(s)
- Fanguo Chen
- School of Life Science, Shandong University, Jinan, P.R. China
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29
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Gübitz G, Schmid MG. Recent advances in chiral separation principles in capillary electrophoresis and capillary electrochromatography. Electrophoresis 2005; 25:3981-96. [PMID: 15597419 DOI: 10.1002/elps.200406173] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This review summarizes recent developments in chiral separation in capillary zone electrophoresis (CZE), electrokinetic chromatography (EKC), and capillary electrochromatography (CEC) covering literature published since the year 2000. New chiral selectors and innovative approaches for CE and CEC are introduced. Recent progress in column technology for CEC is highlighted and the development of new chiral stationary phases is discussed. This review is not dedicated to list applications but will focus on new developments.
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Affiliation(s)
- Gerald Gübitz
- Institute of Pharmaceutical Sciences, Dept. of Pharm. Chemistry, Karl-Franzens-University, Graz, Austria.
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30
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Zhang K, Yan C, Yang J, Zhang Z, Wang Q, Gao R. Preparation and characterization of C16 monolithic columns for capillary electrochromatography. J Sep Sci 2005; 28:217-24. [PMID: 15776922 DOI: 10.1002/jssc.200401873] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A series of methacrylamide-based C16 monolithic columns were prepared and characterized to determine how their porous structural properties and chromatographic behavior are affected by the percentages of functional monomer, base monomer, and cross-linker in the polymerization solution. Baseline separation of 6 neutral compounds can be readily obtained in an optimized column. Furthermore, the effects of organic additive in the mobile phase, operating voltages, and temperature on retention behaviors and separation efficiencies were also studied. The separation mechanism is also discussed. High column efficiency and good reproducibility indicate that the monolithic columns hold considerable promise.
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Affiliation(s)
- Kai Zhang
- State Key Laboratory of Elemento-Organic Chemistry, Nankai University, 94 Weijin Road, Tianjin 300071, China.
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31
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Kahle V, Kost'ál V, Zeisbergerová M. Sample injection in capillary electrochromatography by heart-cut technique. J Chromatogr A 2004; 1044:259-65. [PMID: 15354446 DOI: 10.1016/j.chroma.2004.04.054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The splitter working in heart-cut regime was used for sample injection in capillary electrochromatography. The principle was implemented in an automated microgradient system allowing to inject from microlitre down to nanolitre volumes with high repeatability and minimal extra-column band broadening. The apparatus is able to deliver discrete volumes of liquids at a preset volumetric flow rate and to stop and restore the flow at any moment. This brings a high degree of liquid manipulation flexibility. An extremely low split ratio is sufficient during the analysis, which saves mobile phase consumption substantially. The key parameters influencing the function of the heart-cut splitter were characterised. The function of the apparatus was demonstrated under isocratic, preconcentration and gradient capillary electrochromatography separation conditions. In all cases the statistic evaluation of the main parameters was performed, showing that high repeatability of retention times, peak heights and areas was achieved.
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Affiliation(s)
- Vladislav Kahle
- Institute of Analytical Chemistry, Academy of Sciences of the Czech Republic, Veverí 97, 611 42 Brno, Czech Republic.
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32
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Abstract
A review is presented on the current state of the art and future trends in the development of sol-gel stationary phases for capillary electrochromatography (CEC). The design and synthesis of stationary phases with prescribed chromatographic and surface charge properties represent challenging tasks in contemporary CEC research. Further developments in CEC as a high-efficiency liquid-phase separation technique will greatly depend on new breakthroughs in the area of stationary phase development. The requirements imposed on CEC stationary phase performance are significantly more demanding compared with those for HPLC. The design of CEC stationary phase must take into consideration the structural characteristics that will provide not only the selective solute/stationary phase interactions leading to chromatographic separations but also the surface charge properties that determine the magnitude and direction of the electroosmotic flow responsible for the mobile phase movement through the CEC column. Therefore, the stationary phase technology in CEC presents a more complex problem than in conventional chromatographic techniques. Different approaches to stationary phase development have been reported in contemporary CEC literature. The sol-gel approach represents a promising direction in this important research. It is applicable to the preparation of CEC stationary phases in different formats: surface coatings, micro/submicro particles, and monolithic beds. Besides, in the sol-gel approach, appropriate sol-gel precursors and other building blocks can be selected to create a stationary phase with desired structural and surface properties. One remarkable advantage of the sol-gel approach is the mild thermal conditions under which the stationary phase synthesis can be carried out (typically at room temperature). It also provides an effective pathway to integrating the advantageous properties of organic and inorganic material systems, and thereby enhancing and fine-tuning chromatographic selectivity of the created hybrid organic-inorganic stationary phases. This review focuses on recent developments in the design, synthesis, characterization, properties, and applications of sol-gel stationary phases in CEC.
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Affiliation(s)
- Wen Li
- Department of Chemistry, University of South Florida, Tampa, FL 33620-5250, USA
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33
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Chapter 14 Chromatography of amino acids and peptides. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/s0301-4770(04)80027-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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34
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Zhang K, Gao R, Jiang Z, Yao C, Zhang Z, Wang Q, Yan C. Pressurized capillary electrochromatography separation of peptides with strong cation exchange and hydrophilic interaction. J Sep Sci 2003. [DOI: 10.1002/jssc.200301590] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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35
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Gong Y, Xiang Y, Yue B, Xue G, Bradshaw JS, Lee HK, Lee ML. Application of diaza-18-crown-6-capped beta-cyclodextrin bonded silica particles as chiral stationary phases for ultrahigh pressure capillary liquid chromatography. J Chromatogr A 2003; 1002:63-70. [PMID: 12885079 DOI: 10.1016/s0021-9673(03)00732-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Two bonded chiral stationary phases (CSPs), 8-aminoquinoline-2-ylmethyl- and 8-aminoquinoline-7-ylmethyl-diaza-18-crown-6-capped [3-(2-O-beta-cyclodextrin)-2-hydroxypropoxy]propylsilyl silica particles (non-porous, 1.5 microm), have been prepared and evaluated using capillary liquid chromatography at high pressures (> or = 8000 p.s.i.). High column efficiency (up to 400 000 plates m(-1)) was achieved for chiral separations. These CSPs with two recognition sites, i.e. substituted-diaza-18-crown-6 and beta-cyclodextrin combined with high chromatographic efficiency provide good resolution of a variety of enantiomers and positional isomers in relatively short times under reversed-phase conditions. After inclusion of a Ni (II) ion from the mobile phase, the positively charged crown ether-capped beta-cyclodextrin facilitates specific static, dipolar, and host-guest complexation interactions with solutes.
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Affiliation(s)
- Yinhan Gong
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
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36
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Zhang K, Jiang Z, Yao C, Zhang Z, Wang Q, Gao R, Yan C. Separation of peptides by pressurized capillary electrochromatography. J Chromatogr A 2003; 987:453-8. [PMID: 12613841 DOI: 10.1016/s0021-9673(02)02063-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A pressurized electrochromatography (pCEC) instrument with gradient capability was used in this work for separation of peptides. Three separation modes, namely, pCEC, high-performance liquid chromatography and capillary electrophoresiscan be carried out with the instrument. In pCEC mode, the mobile phase is driven by both electroosmotic flow and pressurized flow, facilitating fine-tuning in selectivity of neutral and charged species. A continuous gradient elution can be carried out conveniently on this instrument, which demonstrates that it is more powerful than isocratic pCEC for separation of complicated samples. The effects of applied voltage, supplementary pressure and ion-pairing agents on separation of peptides in gradient pCEC were investigated. The effects of flow-rate of the pump and the volume of the mixer on resolution were also evaluated.
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Affiliation(s)
- Kai Zhang
- State Key Laboratory of Elemento-Organic Chemistry, Nankai University, 94 Weijin Road, Tianjin 300071, China
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37
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38
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Grobuschek N, Schmid MG, Koidl J, Gübitz G. Enantioseparation of amino acids and drugs by CEC, pressure supported CEC, and micro-hPLC using a teicoplanin aglycone stationary phase. J Sep Sci 2002. [DOI: 10.1002/1615-9314(20021101)25:15/17<1297::aid-jssc1297>3.0.co;2-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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39
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40
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Vickers PJ, Smith NW. Normal-phase chiral separations by pressure assisted capillary electrochromatography using the Pirkle type stationary phase Whelk-O 1. J Sep Sci 2002. [DOI: 10.1002/1615-9314(20021101)25:15/17<1284::aid-jssc1284>3.0.co;2-g] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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41
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Stahl M, Jakob A, von Brocke A, Nicholson G, Bayer E. Comparison of different setups for one- and two-dimensional capillary high-performance liquid chromatography and pressurized capillary electrochromatography coupled on-line with mass spectrometry. Electrophoresis 2002; 23:2949-62. [PMID: 12207303 DOI: 10.1002/1522-2683(200209)23:17<2949::aid-elps2949>3.0.co;2-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A comparison of different separation methods (high-performance liquid chromatography (HPLC), capillary HPLC (CHPLC) and pressurized capillary electrochromatography (pCEC)) coupled on-line with mass spectrometry (MS) is undertaken using the separation of a crude extract of ergot fungus (secalis cornuti) as an example. New and simple setups for a two-dimensional CHPLC coupled on-line with electrospray ionization (ESI)-MS (2D-CHPLC-MS) as well as for capillary size-exclusion chromatography performed under pCEC conditions and coupled on-line with ESI-MS (CSEC-pCEC-MS) are shown. In addition, an improved method for column packing is presented.
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MESH Headings
- Chromatography, High Pressure Liquid/instrumentation
- Chromatography, High Pressure Liquid/standards
- Chromatography, Micellar Electrokinetic Capillary/instrumentation
- Chromatography, Micellar Electrokinetic Capillary/standards
- Claviceps/chemistry
- Electrophoresis, Capillary/instrumentation
- Electrophoresis, Capillary/standards
- Electrophoresis, Gel, Two-Dimensional/instrumentation
- Electrophoresis, Gel, Two-Dimensional/standards
- Equipment Design
- Ergotamines/analysis
- Ergotamines/isolation & purification
- Online Systems
- Peptide Fragments/analysis
- Peptide Fragments/isolation & purification
- Proteins/analysis
- Proteins/isolation & purification
- Spectrometry, Mass, Electrospray Ionization/instrumentation
- Spectrometry, Mass, Electrospray Ionization/standards
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Affiliation(s)
- Mark Stahl
- Institut für Organische Chemie, Universität Tübingen, Tübingen, Germany.
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42
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Abstract
This review is based on a selection of research papers published mainly in the last decade and it describes various analytical aspects of separation and detection of neuroactive steroids in biological matrices.
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43
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Tegeler T, El-Rassi Z. Surfactant-mediated capillary electrochromatography with octadecyl-silica- packed capillary columns for the separation of nonpolar compounds. Case of pyrethroid insecticides. Electrophoresis 2002; 23:1217-23. [PMID: 12007119 DOI: 10.1002/1522-2683(200205)23:9<1217::aid-elps1217>3.0.co;2-c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Capillary electrochromatography (CEC) with octadecyl-silica-packed capillary columns was evaluated in the separation of nonpolar compounds, e.g., pyrethroid insecticides, using surfactant-rich mobile phases. This novel concept is referred to as surfactant-mediated capillary electrochromatography (SM-CEC), and is based on including a charged surfactant, namely sodium di-2-ethylhexyl sulfosuccinate (DOSS), in the mobile phase. Under these conditions, DOSS plays the role of a slowly moving pseudostationary phase so that solutes are partitioned between a mobile phase, a fixed stationary phase and a slowly moving pseudostationary phase. The SM-CEC system was investigated with pyrethroid insecticides over a wide range of DOSS and acetonitrile concentrations in the mobile phase. Pyrethroid insecticides, which are very hydrophobic solutes consisting of geometric isomers and diastereomers, were better resolved in SM-CEC than in straight CEC.
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Affiliation(s)
- Tony Tegeler
- Department of Chemistry, Oklahoma State University, Stillwater, OK 74078-3071, USA
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44
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De Boer T, Mol R, De Zeeuw RA, De Jong GJ, Sherrington DC, Cormack PAG, Ensing K. Spherical molecularly imprinted polymer particles: a promising tool for molecular recognition in capillary electrokinetic separations. Electrophoresis 2002; 23:1296-300. [PMID: 12007129 DOI: 10.1002/1522-2683(200205)23:9<1296::aid-elps1296>3.0.co;2-2] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Spherical molecularly imprinted polymer particles obtained via precipitation polymerization, were introduced as a pseudostationary phase in capillary electrophoresis (CE) to study molecular recognition. Analyses were performed via a partial filling technique using (+)-ephedrine-imprinted microspheres (100-200 nm) which were polymerized from methacrylic acid and 1,1,1-Tris(hydroxymethyl)propanetrimethacrylate using acetonitrile as the solvent. The influence of pH and the modifier content on the separation was investigated. A 0.1% w/v suspension in an aqueous 10 mM phosphate buffer (pH 2.5 with 40% acetonitrile) was hydrodynamically injected into the CE system (80% of the effective capillary length) and led to full baseline separation of racemic ephedrine within 10 min.
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Affiliation(s)
- Theo De Boer
- Department of Analytical Chemistry and Toxicology, University Centre for Pharmacy, Groningen, The Netherlands
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45
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Abstract
At present, the main limitation for the further adoption of capillary electrochromatography (CEC) in the (routine) laboratory is caused by the lack of reproducible and stable columns. The main source of column instability is concentrated in the frits needed to retain the packed bed inside the CEC capillary. The sintering process used to prepare the frits can be rather problematic and irreproducible, particularly for small stationary phase particles and wide column diameters. Since the (surface) composition of the frits is different from the bulk stationary phase packing, different electroosmotic flow (EOF) velocities are generated. This effect is assumed to be primarily responsible for rapid column destruction. In this contribution, a novel approach for the preparation of fritless CEC capillaries is presented and evaluated. Using 5 microm Hypersil ODS particles, separation efficiencies in the range of 130,000-200,000 plates/m were obtained. In a 100 microm inner diameter packed column, electrical currents up to 50 microA could be tolerated without negative effects such as bubble formation. The prepared CEC columns were found to be stable and could easily be operated continuously for several days without column damage. An additional advantage of the proposed tapering approach is that application of pressure on the in- and outlet vial during separation was not required to prevent bubble formation.
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Affiliation(s)
- Erik Baltussen
- Laboratory of Analytical Biotechnology, Kluyver Institute for Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands
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46
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Charváto J, Kasicka V, Král V, Deyl Z. Capillary electrochromatographic study of the interactions of porphyrin derivatives with amino acids and oligopeptides. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 770:165-75. [PMID: 12013223 DOI: 10.1016/s1570-0232(02)00052-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Open-tubular capillary electrochromatography (OT-CEC) was used to study the interactions of synthetic (metallo)porphyrin derivatives (immobilized by physical adsorption to the fused-silica capillary wall) with three aromatic amino acids (phenylalanine, tyrosine, tryptophan), three aliphatic amino acids (beta-alanine, proline, valine) and two oligopeptides (diglycine, triglycine). The effective mobilities of amino acids and peptides measured in OT-CEC mode in the acid and alkaline background electrolytes (BGEs) were compared with those obtained by capillary zone electrophoresis (CZE) in the bare fused-silica capillary in the same BGEs. In this way the influence of the peripheral substituents and the character of the central metal atom in porphyrin derivatives on the interactions with amino acids and peptides in the acid and alkaline media was investigated. Three types of noncovalent interactions, axial ligation to the central metal atom, pi-pi stacking and electrostatic repulsion seem to take part in the interactions of analyzed amino acids and peptides with porphyrin derivatives, resulting in a better separation of these analytes by OT-CEC than by CZE.
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Affiliation(s)
- Jana Charváto
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague
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47
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Martins JML, Gago-Martinez A, Dabek-Zlotorzynska E, Aranda-Rodriguez R, Lawrence JF. Preliminary results on the application of capillary electrochromatography to the analysis of domoic acid. J Sep Sci 2002. [DOI: 10.1002/1615-9314(20020401)25:5/6<342::aid-jssc342>3.0.co;2-h] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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48
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Vollmerhaus PJ, Tempels FWA, Kettenes-van den Bosch JJ, Heck AJR. Molecular interactions of glycopeptide antibiotics investigated by affinity capillary electrophoresis and bioaffinity electrospray ionization-mass spectrometry. Electrophoresis 2002; 23:868-79. [PMID: 11920871 DOI: 10.1002/1522-2683(200203)23:6<868::aid-elps868>3.0.co;2-#] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Many analytical approaches are available to evaluate (bio)molecular interactions, all of which have their particular advantages and disadvantages. In recent years, two relatively new techniques have emerged that may be used by the bioanalytical community to evaluate such interactions, namely affinity capillary electrophoresis (ACE) and bioaffinity electrospray ionization-mass spectrometry (ESI-MS). In this paper, we describe and evaluate the use of both these techniques for the investigation of the interactions of glycopeptide antibiotics with peptides that mimic the bacterial cell wall binding site. We focus particularly on the effect of the sugar moieties attached to the antibiotic peptide backbone and on the noncovalent dimerization of these glycopeptide antibiotics.
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Affiliation(s)
- Pauline J Vollmerhaus
- Department of Biomolecular Mass Spectrometry, Bijvoet Center for Biomolecular Research, Utrecht University, Sorbonelaan 16, NL-3584 CA Utrecht, The Netherlands
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49
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Abstract
A review is presented of the most important recent applications of capillary electrochromatography (CEC) for the analysis of acidic, basic, and neutral compounds, of biomolecules, environmental substances, natural products, pharmaceuticals, and chiral compounds. Packed-column CEC (packed-CEC), open-tubular (OT-CEC), as well as pressure-assisted CEC (pseudo-CEC) are hereby considered. Papers published between July 1999 and April 2001 were taken into account. Applications before July 1999 have been reviewed in Electrophoresis 1999, 20, 3027-3065.
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Affiliation(s)
- G Vanhoenacker
- Ghent University, Department of Organic Chemistry, Belgium
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50
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Dabek-Zlotorzynska E, Aranda-Rodriguez R, Keppel-Jones K. Recent advances in capillary electrophoresis and capillary electrochromatography of pollutants. Electrophoresis 2001; 22:4262-80. [PMID: 11824642 DOI: 10.1002/1522-2683(200111)22:19<4262::aid-elps4262>3.0.co;2-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
An overview of major developments in capillary electrophoresis and capillary electrochromatography systems in the environmental field is presented, covering relevant publications between the second half of 1999 and early 2001. Contributions are reviewed in relation to developments in detection, sample preparation/preconcentration, precision and applications. Many interesting examples are shown and the influence of important parameters on the performance of developed methods is discussed.
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Affiliation(s)
- E Dabek-Zlotorzynska
- Analysis and Air Quality Division, Environmental Technology Centre, Environment Canada, Ottawa, ON.
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