| Separation Science in modern times means to deal with several challenges: Sample complexity, speediness, demand of new column formats, polar compounds, etc. This online only issue covers both recently published articles and papers attracting large numbers of readers as inferred from numerous hits at the JSS website and many downloads in regard to the development in Column Technologies. Treat yourself, read these articles for free and get valuable information.|
Ionic liquid stationary phases for gas chromatography
Colin F. Poole and Salwa K. Poole
The emphasis in this review is placed on the role of gas chromatography, an area of separation science that has otherwise been almost stagnant for over a decade, played in the design of ionic liquids of low melting point, high thermal stability, high viscosity, and variable selectivity for separations. Ionic liquids provide unprecedented opportunities for extending the selectivity and temperature-operating range of columns in the GC area.
Keywords: Ionic liquids, open tubular columns, Packed columns, Solvation parameter model, Wall coated columns
Cited: 19 times
Cited by Journals: Anal. Chim. Acta, Analyst, Gas Chromatogr., Green Chem., J. Chromatogr. A, J. Chromatogr. B, J. Phys. Chem. B, J. Phys. Chem. C, J. Sep. Sci., Macromolecules, Phys. Chem. Chem. Phys., RSC Adv., Sep. Purif. Technol., Books: Encyclopedia of Analatical Chemistry, Wiley 2012
Size exclusion chromatography – A blessing and a curse of science and technology of synthetic polymers
This critical review gives concise information about macromolecules and their behavior in solution, basic understanding about principles, instrumentation, and application possibilities of size exclusion chromatography and more in detail discusses drawbacks and pitfalls of the method with the emphasis on synthetic polymers. It is shown that this outstanding, extremely useful, simple, robust, and repeatable method may produce erroneous results if appropriate attention is not paid to the conditions of measurement and to the data processing.
Keywords: Limitations, Macromolecules, Pit falls, Practical hints, Retention mechanisms
Cited: 7 times
Cited by Journals: Anal. Bioanal. Chem., Biointerphases, Compr. Biomater., Latin Am. Appl. Res., Macromolecules, Prog. Polym. Sci., Starch – Stärke, Books: Encyclopedia of Analytical Chemistry, Wiley 2012
Characterization of branched polysaccharides using multiple-detection size separation techniques
Francisco Vilaplana and Robert G. Gilbert
The structure of branched polysaccharides involves a hierarchy of levels, from the constituent sugars, over the branching pattern, to the macromolecular architecture, and the supramolecular organization. This review focuses on the best current means to obtain reliable branch chain and size distributions using size-separation technologies coupled with number-, mass- and molecular-weight sensitive detectors. Problems with current technologies are also critically appraised.
Keywords: Branching, FFF separation, Polysaccharides, Size distribution, Shear scission, Starch
Cited: 9 times
Cited by Anal. Bioanal. Chem., Anal. Chim. Acta, Carbohydr. Polym., J. Agric. Food Chem., J. Chromatogr. A, Polymer, Polym. Sci. Compr. Ref., Starch - Stärke
Silica-based and organic monolithic capillary columns for LC: Recent trends in proteomics
Johan Rozenbrand and Wouter P. van Bennekom
This review deals with recent development and applications of the most popular monolithic column materials, focusing on silica-based and organic (polystyrene and methacrylate) monolithic capillary columns for proteomics. The applicability of these columns is illustrated by examples of the analysis of (complex) protein digests and proteins conveniently summarized in tables. Furthermore, characteristics of column materials are compared and future trends and prospects are presented.
Keywords: Continuous bed columns, Monoliths, Open tubular columns, Porous layer
Applications of monolithic columns in liquid chromatography-based clinical chemistry assays
Dustin R. Bunch and Sihe Wang
The goals of this review are to identify the areas of clinical chemistry that analytical monolithic columns have been used in HPLC methods, to demonstrate the application of analytical monolithic columns in HPLC methods using different detection systems and to discuss the advantages and limitations of the monolithic columns compared with particulate columns in the clinical chemistry applications. Monolithic columns are a welcome addition to HPLC methods in the field of clinical chemistry.
Keywords: Clinical diagnostics, Monoliths, Porphyrins, Steroids, Therapeutic drug monitoring, Trace compound analysis, Vitamins
An overview of the use of monoliths in sample preparation and analysis of milk
Victoria F. Samanidou and Eftichia G. Karageorgou
The scope of this review was to provide information on the current use of monolith technology in the analysis of milk in both separation and sample preparation. It is obvious that although when used monoliths have indicated high efficiency in milk analysis, not much work has been done till now. However, the use of monolithic support for analysis and sample preparation is a promising field open to analysts for further investigation.
Keywords: Food safety, Milk proteins, Monoliths
Practical comparison of LC columns packed with different superficially porous particles for the separation of small molecules and medium size natural products
Peilin Yang, Terry McCabe, and Matthias Pursch
Commercial C18 columns packed with superficially porous particles of different sizes and shell thicknesses (Ascentis Express, Kinetex, and Poroshell 120) or sub-2-mm totally porous particles (Acquity BEH) were systematically compared using a small molecule mixture and a complex natural product mixture as text probes. Significant efficiency loss was observed on 2.1-mm id columns even with a low dispersion ultra-high pressure liquid chromatography system.
Keywords: Batch-to-batch variability, Column efficiency, Small molecule analytes, Sub-2 µm particles
Cited: 5 times
Cited by Biomed. Chromatogr., J. Chromatogr. A
Novel Pirkle-type quinine 3,5-dinitrophenylcarbamate chiral stationary phase implementing click chemistry
Karol M. Kacprzak and Wolfgang Lindner
A novel WAX chiral stationary phase based on 3,5-dinitrophenylcarbamoyl quinine immobilized onto silica gel via a 1,2,3-triazole linker has been designed with the intention to modulate the p–p donor–acceptor interaction capacity of a Cinchona-type chiral selector. In fact, the insertion of a p-acidic residue to the chiral selector motif offered an additional binding site for p-donating analytes such as aryloxypropionic acids and profens. This type of CSP offers an attractive expansion of applicability of Cinchona-type CSPs only by re-designing the intermolecular interaction sites, which leads in some cases to significantly improved enantiomer separation.
Keywords: Cinchona alkaloids, Enantioseparation, Quinine
Cited: 2 times
Cited by Chirality, TrAC, Trends Anal. Chem.
A surface plasmon resonance sensor on a compact disk-type microfluidic device
Akihide Hemmi, Takashi Usui, Akihiro Moto, Tatsuya Tobita, Nobuaki Soh, Koji Nakano, Hulie Zeng, Katsumi Uchiyama, Toshihiko Imato, and Hizuru Nakajim
A novel strategy for downsizing a SPR sensor system is presented here. For this purpose, a CD-type SPR sensor system was developed. The SPR sensor does not require an expensive prism and matching oil. Since pumps and valves are also unnecessary, the CD-type SPR sensor would be useful for on-site analysis, such as environmental monitoring, food safety testing and point-of-care testing.
Keywords: Centrifugal force, Chip, Immunoassay, Microfluidics
Cited: 1 time
Cited by: Lab Chip
Improved preparation of chiral stationary phases via immobilization of polysaccharide derivative-based selectors using diisocyanates
Shouwan Tang, Guihua Liu, Xiaofang Li, Zhaolei Jin, Fang Wang, Fuyou Pan, and Yoshio Okamoto
Four immobilized polysaccharide derivative-based CSPs were prepared. The improved procedure avoided the derivatization and regeneration of 6-hydroxyl groups of cellulose and amylose, which is a big advantage in respect to rapidness and convenience. The obtained immobilized CSPs demonstrated good solvent durability and eluents containing THF or chloroform can be used and some of the racemates could be better resolved. Moreover, some acidic and basic chiral compounds were effectively resolved on the newly prepared CSPs.
Keywords: Chiral compounds, Enantioseparation
Preparation and chiral recognition in HPLC of cellulose 3,5-dichlorophenylcarbamates immobilized onto silica gel
Hai-tao Qu, Jun-qing Li, Guang-shun Wu, Jun Shen, Xian-de Shen, and Yoshio Okamoto
A one-pot method was carried out to synthesize the cellulose 3,5-dichlorophenylcarbmates (2) bearing small amounts of 3-(triethoxysilyl)propyl residues, which could be efficiently immobilized onto silica gel surface through polycondensation. The chiral recognition abilities of the immobilized CPMs 2 were similar to that of the 2-coated CPM and slightly different from that of the commercial Chiralpak IC. Eluents such as chloroform and THF could be used for the immobilized CPMs without any damage and many racemates were better resolved on the immobilized CPMs.
Keywords: Chiral packing material, Enantioseparation
Cited: 2 times
Cited by Central Eur. J. Chem., J. Solid State Electrochem.
Chromatographic characteristics of poly(1-vinylimidazole)-grafted silica in normal-phase HPLC
Min Sun, Juanjuan Feng, Shujuan Liu, Xusheng Wang, Xia Liu, and Shengxiang Jiang
A stationary phase based on poly(1-vinylimidazole)-grafted silica has been prepared by surface radical chain-transfer reaction and characterized. The results showed that both weak polar compounds (polycyclic aromatic hydrocarbons, dialkyl phthalates) and polar compounds (anilines, phenols) could be successfully separated, implying better separation performance than blank silica and conventional aminopropyl-bonded silica under the same conditions.
Keywords: Radical polymerization, Stationary phases
Cited: 1 time
Cited by Anal. Chim. Acta
Optimization of the synthesis of a hyper-crosslinked stationary phases: A new generation of highly efficient, acid-stable hyper-crosslinked materials for HPLC
Yu Zhang, Yuming Huang, and Peter W. Carr
The purpose of this study is to identify a set of synthetic conditions that will allow to further reduce metal contamination during the development of HC phases. Recently, a new family of hyper-crosslinked phases was developed for the use under very aggressive conditions. The results indicate that this new generation of acid stable HC phases should be very useful in separating bases or biological analytes in acidic media, especially at elevated temperatures.
Keywords: Column packing, Peptides, Pore size distribution, Separation efficiency
Cited: 2 times
Cited by J. Chromatogr. A, J. Sep. Sci.
Purification of compounds from Lignum Dalbergia Odorifera using two-dimensional preparative chromatography with Click oligo (ethylene glycol) and C18 column
Jiatao Feng, Yuansheng Xiao, Zhimou Guo, Danhua Yu, Yu Jin, and Xinmiao Liang
Purification of compounds from traditional Chinese medicines is an important task for understanding the chemical composition of such compounds. Here, a two-dimensional purification method based on a Click oligo (ethylene glycol) column and a C18 column was developed to realize an orthogonal separation in preparative level for purifying compounds efficiently. The results indicate, that this method can improve the separation of a complex sample and increase the purity of the compounds.
Keywords: Complex Samples, Orthogonal separation, Traditional Chinese Medicin
Cited: 2 times
Cited by Anal. Bioanal. Chem., J. Sep. Sci.
Incorporation of carbon nanotubes in a silica HPLC column to enhance the chromatographic separation of peptides: Theoretical and practical aspects
Claire André, Rania Aljhani, Tijani Gharbi, and Yves C. Guillaume
The retention mechanism of a series of peptides was analyzed on a single-wall carbon nanotube (SWCNT) stationary phase. The thermodynamic properties trends were determined over a wide range of ACN fraction x in an ACN/water mixture. The model proposed explains these variations in terms of organization of the organic modifier, here ACN, in clusters in the ACN/water mixture and on the steric and specific electronic forces due to the unique structure of SWCNT. The importance of the role of ACN to reduce the analysis time without diminishing the separation quality could be also clearly visualized.
Keywords: Acetonitrile, Nanoscience, Thermodynamics
Cited: 5 times
Cited by Anal. Chim. Acta, Lab Chip, J. Sep. Sci., Talanta
Improved chromatographic performances of glycidyl methacrylate anion-exchange monolith for fast nano-ion exchange chromatography
Anthony Bruchet, Vincent Dugas, Clarisse Mariet, Florence Goutelard, and Jérôme Randon
Here, it could be shown that the transfer of well-established thermally induced polymerization to photo-induced polymerization can be a relevant way to enhance the ion exchange chromatography of glycidyl-based monolith. The efficiency of the monolith was not retention-dependent, demonstrating its wide range of possible applications for highly retained anions.
Keywords: Chemical functionalization, Kinetics, Photopolymerization, Robustness, Surface roughness
Cited: 1 time
Cited by Anal. Biochem.
Separation of peptide diastereomers using CEC and a hydrophobic monolithic column
Ronny Ludewig, Jing Dong, Hanfa Zou, and Gerhard K. E. Scriba
A neutral hydrophobic monolith prepared by radical in situ copolymerization of lauryl methacrylate and ethylene dimethacylate has been evaluated for CEC separation of diastereomers of small peptides. Using an acidic mobile phase containing ACN as organic modifier, the peptides migrated due to their own electrophoretic mobility and the hydrophobic interactions with the stationary phase contributed to the separation. The results clearly demonstrate that CEC offers additional separation mechanisms and may be superior to CZE or HPLC in certain cases.
Keywords: Acetonitrile, Chiral stationary phase, Dipeptides, Radical in situ copolymerization
Cited: 2 times
Cited by ELECTROPHORESIS, J. Sep. Sci.
Some new selective stationary phases for RP-HPLC
Isabel C. S. F. Jardim, Liane Maldaner, Josimara Lourenço, Livia M. A. Fioravanti, and Carol H. Collins
Application and stability studies of new stationary phases with directed selectivities, phenyl group- and trifluoropropyl-containing siloxanes are described. The phenyl-containing phases showed excellent characteristics related to the separation of several different types of aromatic compounds while the fluorinated phases, which present a more polar character, revealed selectivity for the separation of positional isomers as well as for a mixture of basic pharmaceuticals.
Keywords: Column packing, Fluorinated phases, Phenyl phases, Stability
Cited: 5 times
Cited by J. Anal. Atom. Spectrom., J. Chromatogr. A, J. Sep. Sci., Talanta
Monolithic poly(ethylhexyl methacrylate-co-ethylene dimethacrylate) column with restricted access layers prepared via reversible addition-fragmentation chain transfer polymerization
Mamat Turson, Man Zhou, Ping Jiang, and Xiangchao Dong
A poly(EHMA-co-EDMA) monolithic column was synthesized via in situ RAFT polymerization. Using RAFT polymerization gives more homogeneous structures, which results in higher column efficiency compared with traditional polymerization. The hydrophilic layer modified column shows a better ability of protein exclusion, while the selectivity for hydrophobic compound remains unchanged. This indicates that the material has the property of RAM and application potential in drug analysis.
Keywords: Capillary monoliths, Hydrophilic chain modification, Multifunctional material, Proteins
Cited: 4 times
Cited by Adv. Healthcare Mater., Anal. Chem., J. Sep. Sci., TrAC, Trends Anal. Chem.
Physical characterization and evaluation of HPLC columns packed with superficially porous particles
Jared S. Baker, John C. Vinci, Amber D. Moore, and Luis A. Colón
Two HPLC columns packed with superficially porous packing material (KinetexTM 1.7 and 2.6 mm C18 particles) were evaluated in terms of their physical properties and performance characteristics. The use of superficially porous technology can make rapid, high efficiency separations more accessible to demanding applications such as the high throughput analyses needed for drug discovery processes. Although the superficially porous approach to produce HPLC particles has been known for some time, the relatively new type of columns represents a remarkable achievement in column technology.
Keywords: Column packing, Column porosity
Cited: 11 times
Cited by Anal. Chem., Anal. Chim. Acta, J. Chromatogr. A, J. Sep. Sci.
HILIC behavior of a reversed-phase/cation-exchange/anion-exchange trimode column
Xiaodong Liu and Christopher A. Pohl
The HILIC behavior of the newly developed RP/WAX/strong cation exchange (SCX) trimodal stationary phase using highly hydrophilic anionic, cation and neutral analytes was investigated. It could be demonstrated that the new phase exhibits hydrophilic interaction liquid chromatography characteristics: At high acetonitrile levels, the retention for charged analytes is governed by an ion-exchange process, accompanied by hydrophilic interaction. This feature provides good flexibility in pharmaceutical method development such as simultaneous separation of hydrophilic drug molecule and its counterions.
Keywords: Counterions, Hydrophilicity, Pharmaceuticals, Retention dependency
Cited: 12 times
Cited by Journals: Anal. Bioanal. Chem., Anal. Chim. Acta, Analyst, Central Eur. J. Chem., J. Chromatogr. A, J. Sep. Sci., TrAC Trends Anal. Chem., Books: Hydrophilic Interaction Liquid Chromatography (HILIC) and Advanced Applications, Perry G . Wang and Weixuan He, CRC Press 2011
Synthesis of core-shell molecularly imprinted polymer microspheres by precipitation polymerization for the inline molecularly imprinted solid-phase extraction
Francisco Barahona, Esther Turiel, Peter A. G. Cormack, and Antonio Martín-Esteban
In this work, a new surface-imprinted stationary phase designed specifically for liquid chromatography applications has been prepared. MIP microspheres with a core-shell morphology were prepared by a two-step polymerization strategy. These porous spherical particles showed selective molecular recognition properties confined to the outer surfaces of the particles, which led to an enhanced chromatographic performance.
Keywords: Core-shell particles, Food, Microspheres, Molecular imprinting
Cited: 6 times
Cited by Journals: Food Anal. Methods, J. Chromatogr. A, J. Membr. Sci., J. Sep. Sci., Books: Comprehensive Sampling and Sample Preparation, P. Manesiotis, L. Fitzhenry, G. Theodoridis, P. Jandera, Elsevier 2012
Characterization of the adult zebrafish cardiac proteome using online pH gradient strong cation exchange-RP 2D LC coupled with ESI MS/MS
Jiang Zhang, Kevin A. Lanham, Richard E. Peterson, Warren Heideman, and Lingjun Li
An online pH gradient SCX-RP HPLC MS/MS platform for global analysis of the adult zebrafish heart proteome is introduced. The pH gradient SCX method proved to be an effective alternative for the conventional salt gradient SCX method and demonstrated excellent resolution for tryptic peptides generated from complex tissue proteome sample. A two-step sample preparation technique to extract zebrafish heart proteins that combined the advantages of conventional tryptic digestion and microwave assisted hydrolysis proves to be effective in expanding the protein identification for complex tissue samples. Using this integrated platform, over 1300 proteins from adult zebrafish heart samples could be identified.
Keywords: Heart, Cardiac proteins, Danio rerio, Microwave assisted digestion, Proteomics
Cited: 6 times
Cited by Anal. Chim. Acta, J. Chromatogr. A, J. Mass Spectrom., Mass Spectrom. Rev., PROTEOMICS
Fast, accurate, and convenient analysis of bed densities for columns packed with fine reversed-phase particles
Stephanie Jung, Daniela Stoeckel, and Ulrich Tallarek
Interparticle porosities of commercially available, analytical, reversed phase HPLC columns by Donnan exclusion of a small, unretained, co-ionic tracer were determined. The columns contained packings of C18-modified, endcapped, silica particles, which differed in their nominal particle diameters (1.8–5 mm) and construction (fully porous or core-shell). Experiments were carried out by monitoring the elution volumes of nitrate samples in a mobile phase of acetonitrile/water 80:20 v/v at increasing concentrations of Tris-HCl buffer (pH 8.1) from 0.01 to 60 mM. Clearly defined plateau regions were observed for all columns, even those densely packed with core-shell and sub-2 mm particles, enabling the accurate determination of interparticle porosities to three decimal places in a fast and convenient way.
Keywords: Column packing, Core-shell particles, Donnan exclusion, Interparticle porosity, Sub-2-µm particles
Cited: 2 times
Cited by J. Chromatogr. A