Download or read book Stationary Phase Solvation and the Retention Mechanism in Reversed phase Liquid Chromatography written by Lynn Alison Cole and published by . This book was released on 1990 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Study of Retention Mechanism in Reversed Phase Liquid Chromatography written by Lay Choo Tan and published by . This book was released on 1994 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Understanding Retention Mechanisms and Adjusting Selectivity of Basic Pharmaceutical Separations by Reversed phase Liquid Chromatography written by Jun Dai and published by . This book was released on 2005 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Chromatography written by Nelu Grinberg and published by CRC Press. This book was released on 2017-08-15 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: For more than five decades, scientists and researchers have relied on the Advances in Chromatography series for the most up-to-date information on a wide range of developments in chromatographic methods and applications. For Volume 54, the series editors have invited established, well-known chemists to offer cutting-edge reviews of chromatographic methods applied in the life sciences that emphasize the underlying principle of separation science. The clear presentation of topics and vivid illustrations for which this series has become known makes the material accessible and engaging to analytical, biochemical, organic, polymer, and pharmaceutical chemists at all levels of technical skill.
Download or read book Liquid Chromatography written by Salvatore Fanali and published by Elsevier. This book was released on 2023-04-20 with total page 886 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid Chromatography: Fundamentals and Instrumentation, Third Edition offers a single source of authoritative information on all aspects of the practice of modern liquid chromatography. The book gives those working in academia and industry the opportunity to learn, refresh, and deepen their understanding of the field by covering basic and advanced theoretical concepts, recognition mechanisms, conventional and advanced instrumentation, method development, data analysis, and more. This third edition addresses new developments in the field with updated chapters from expert researchers. The book is a valuable reference for research scientists, teachers, university students, industry professionals in research and development, and quality control managers. Emphasizes the integration of chromatographic methods and sample preparation Provides important data related to complex matrices, sample preparation, and data handling Gives background information to facilitate the choice of LC sub-technique and experimental conditions, mobile and stationary phases, detectors, data processing, and more Offers comprehensive updates to all chapters Includes new chapters on chiral recognition, co-solvents and mobile phase additives, physicochemical measurements, and identification and quantitation in mass spectrometry
Download or read book Retention and Selectivity in Liquid Chromatography written by R.M. Smith and published by Elsevier. This book was released on 1995-01-13 with total page 479 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book brings together a number of studies which examine the ways in which the retention and selectivity of separations in high-performance liquid chromatography are dependent on the chemical structure of the analytes and the properties of the stationary and mobile phases. Although previous authors have described the optimisation of separations by alteration of the mobile phase, little emphasis has previously been reported of the influence of the structure and properties of the analyte. The initial chapters describe methods based on retention index group increments and log P increments for the prediction of the retention of analytes and the ways in which these factors are influenced by mobile phases and intramolecular interactions. The values of a wide range of group increments in different eluents are tabulated. Different scales of retention indices in liquid chromatography are described for the comparison of separations, the identification of analytes and the comparison of stationary phases. Applications of these methods in the pharmaceutical, toxicology, forensic, metabolism, environmental, food and other fields are reviewed. The effects of different mobile phases on the selectivity of the retention indices are reported. A compilation of sources of reported retention index values are given. Methods for the comparison of stationary phases based on the interactions of different analytes are covered, including lipophilic and polar indices, shape selectivity comparisons, their application to novel stationary phases, and chemometric methods for column comparisons.
Download or read book Investigation and Control of Alkylsilane Stationary Phase Structure in Reversed Phase Liquid Chromatography written by and published by . This book was released on 2006 with total page 726 pages. Available in PDF, EPUB and Kindle. Book excerpt: Investigation and control of alkylsilane stationary phase structure in reversed phase liquid chromatography is presented. Raman spectroscopy is used to probe thealkyl chain conformational order and interchain coupling as a function of various chromatographic conditions. A new method is further developed to fabricate alkylsilane stationary phases with controlled surface coverage. The alkyl chain conformational order and interchain coupling of a series of high-density docosylsilane (C22) bonded stationary phases is shown as a function of temperature, surface coverage, polymerization method, common solvents and solutes. The conformational order of C22 stationary phases is compared to that of octadecylsilane (C18) stationary phases to understand the chain length effect on stationary phase structure. The conformational order information as indicated by Raman spectral order indicators for a C22 phase are correlated with the capacity factor and separation efficiency for each solute studied to gain insight into the retention mechanism. These studies help to understand the origin of stationary phase shape selectivity and the separation process in general. Based on these results, the molecular pictures at the stationary phase/solvent interface are proposed. The effect of pressurized solvent environments on two C18 phases is studied to obtain direct evidence for changes in stationary phase structure due to pressure. These changes are compared to effects of solvation relative to air in the same solvents. In addition, Raman spectral order indicators are identified for perdeuterated alkyl-containing system. This study provides a foundation for studying stationary phase structure in complex systems comprised of long alkyl-containing solutes. A further development of a new method is presented as well for synthesizing alkylsilane stationary phases with precisely controlled surface coverage by using a displaceable surface template monolayer of n-alcohol. A mechanism for this process is proposed based on the studies of n-alcohol concentration and chain length effect on the stationary phase surface coverage. The utility of these new stationary phases as chromatographic support is demonstrated. The shape selectivity for these new phases is comparable to or better than similar phases prepared by conventional methods.
Download or read book Measurements of Limiting Activity Coefficients of Homologous Series of Solutes and Their Application to the Study of Retention Mechanism in Reversed Phase Liquid Chromatography written by Won Jo Cheong and published by . This book was released on 1989 with total page 690 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Methods for the Characterization of Electrostatic Interactions on Surface confined Ionic Liquid Stationary Phases for High Pressure Liquid Chromatography written by Patrice Renée Fields and published by . This book was released on 2011 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: This body of work is a continuation of work previously completed in our group that examines the retention properties of surface confined ionic liquid (SCIL) stationary phases under reversed-phase and supercritical fluid chromatographic conditions. SCIL's have been shown to be useful for separating a variety of both organic and inorganic compounds. However, there has been little work done to elucidate the different retention mechanisms and properties that allow for the wide range of retention modes observed. The first chapter provides a brief history and survey of the properties of ionic liquids. The first chapter also includes an overview of the linear solvation free energy relationship (LSER), which is used to characterize the retention of solute sets containing both neutral and ionizable compounds in under reversed-phase and supercritical conditions. This chapter also provides insight into the evolution and development of molecular solute descriptors. The second chapter discusses several methods that can be employed to modify the LSER model to account for electrostatic interactions between the SCIL stationary ohases and ionizable solutes in reversed-phase chromatography. The P, D and J solute descriptors are evaluated based on their ability to fit the retention of ionizable solutes to the LSER model and to produce coefficient values that are consistent with the underlying molecular interactions and what has been previously reported in reversed-phase studies. The third chapter investigates the use of the LSER model to characterize the retention mechanism of two SCIL stationary phases under supercritical conditions. The LSER coefficients generated via the multiple linear regression of chromatographic retention data are compared and analyzed for statistical difference from one another. The two SCIL phases are further compared to a 2-ethylpyridine (EP) stationary phase, which is more commonly used in chromatography with compressible fluids. This chapter further examines the viability of the P and J solute descriptors to describe the electrostatic interactions between the SCIL stationary phases and ionizable solutes under supercritical conditions. The fourth chapter examines the ion exchange properties of several SCIL stationary phases. A series of small inorganic ions in acetonitrile-water mixtures are used to probe mechanistic differences in the stationary phases due to the substituents attached to the exchange moiety after correcting for loading differences between the phases. Connections have been made between the observed retention properties and the solvation of both the anion analytes and the stationary phase. The fifth chapter summarizes the findings of the previous chapters and offers suggestions for the future directions for this project while the appendix describes a method for estimating the viscosity of binary and ternary supercritical fluids. The estimates are based on a form of Darcy's law and relates the effect of temperature, pressure and flow rate on the estimates.
Download or read book Liquid Chromatography written by R. Kaliszan and published by Elsevier Inc. Chapters. This book was released on 2013-01-08 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: In view of linear free-energy relationships, LFER, chromatographic systems are “free-energy transducers,” translating differences in the structure of analytes into quantitative differences in physicochemical properties, like retention parameters. Hence, quantitative structure property (retention) relationships, QSP(R)R, bear valuable information on analytes and the separation systems involved. We illustrate here what can be achieved from the statistically valid and physically meaningful quantitative structure-retention relationships, QSRR. In particular, one can predict retention data, confirm identification, and optimize conditions of separation of given structurally defined analytes. Also, QSPR can shed light on the molecular mechanism of separation operating on specific stationary phases. Additionally, one can assess such properties of drug analytes of pharmacokinetic importance, like lipophilicity and acidity. Also, differences in interactions of xenobiotics with biomacromolecule components of chromatographic systems can conveniently be quantified. By means of QSRR, the chromatographic behavior of analytes in diverse separation systems can be related to their pharmacological properties.
Download or read book Quantitative Structure written by Roman Kaliszan and published by Wiley-Interscience. This book was released on 1987-10-14 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of computers in numerical characterization of molecular structures has given chemists fundamentally new information on chemical structures, leading to major developments in physical, analytical, and medicinal chemistry. This book, written by a pioneer in the field, extends and updates research on quantitative structure retention relationships (QSRR) by consolidating and critically reviewing the extensive literature on the subject while providing basic theoretical and practical information required in all investigations involving chromatography, analytical chemistry, biochemistry, and pharmaceutical research. Coverage includes detailed discussions of the general theories and mechanisms of chromatographic separations, prediction of retention coefficients, statistical techniques and formal requirements of QSRR studies, specific applications of chromatographic data, and much more. Also provides several carefully selected figures and tables plus extensive bibliographies.
Download or read book Reversed Phase High Performance Liquid Chromatography written by Ante M. Krstulovic and published by . This book was released on 1982-05-04 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive problem-solving approach to reversed-phase high-performance liquid chromatography covering the theoretical aspects and practical information needed in diverse areas of research. Also reviews RPLC applications in the biomedical/biochemical field.
Download or read book Liquid Chromatography written by Salvatore Fanali and published by Elsevier. This book was released on 2017-06-22 with total page 808 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid Chromatography: Fundamentals and Instrumentation, Second Edition, is a single source of authoritative information on all aspects of the practice of modern liquid chromatography. It gives those working in both academia and industry the opportunity to learn, refresh, and deepen their understanding of new fundamentals and instrumentation techniques in the field. In the years since the first edition was published, thousands of papers have been released on new achievements in liquid chromatography, including the development of new stationary phases, improvement of instrumentation, development of theory, and new applications in biomedicine, metabolomics, proteomics, foodomics, pharmaceuticals, and more. This second edition addresses these new developments with updated chapters from the most expert researchers in the field. Emphasizes the integration of chromatographic methods and sample preparation Explains how liquid chromatography is used in different industrial sectors Covers the most interesting and valuable applications in different fields, e.g., proteomic, metabolomics, foodomics, pollutants and contaminants, and drug analysis (forensic, toxicological, pharmaceutical, biomedical) Includes references and tables with commonly used data to facilitate research, practical work, comparison of results, and decision-making
Download or read book A Study of the Mechanism of Retention in Reversed phase Liquid Chromatography written by Thomas Gerard Burke and published by . This book was released on 1980 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigating a Model Reversed phase Liquid Chromatography Stationary Phase with Vibrationally Resonant Sum Frequency Generation Spectroscopy written by Arthur D. Quast and published by . This book was released on 2011 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reversed-phase liquid chromatography (RPLC) is a widely used technique for analytical separations but routinely requires empirical optimization. Gaining a better understanding of the molecular reasons for retention may mean more efficient separations with fewer trial and error runs to obtain optimized separations. Vibrationally resonant sum frequency generation (VR-SFG) is a surface specific technique that has allowed for in situ examination of model RPLC stationary phases under various solvent and pressure conditions. In order to improve on past work with model RPLC stationary phases two challenges had to be overcome. First, improved vibrational mode assignments of the C18 stationary phase were needed for proper understanding of this model system. Second, the synthesis of back-surface reference mirrors used in these VR-SFG experiments allowed us to better correct the relative intensities of the various spectral peaks present in typical spectra. After examination of model RPLC systems under various conditions, we have found that these model substrates have a significant amount of interference from nonresonant signal. This interference of resonant and nonresonant signals on fused silica surfaces has not been previously examined and further studies of the model RPLC stationary phase must properly deal with the non-negligible nonresonant interference that is present. We have seen changes in the VR-SFG spectra of these model systems under a variety of conditions including elevated pressure, however the changes are mostly due to nonresonant interference. These spectral changes, although apparently not solely from structural changes, need to be investigated further to better understand the molecular basis of retention in model RPLC systems.
Download or read book Novel Stationary Phases on Silica and Zirconia for the Reversed Phase High Performance Liquid Chromatographic Separation of Acidic and Basic Analytes written by Brian Charles Trammell and published by . This book was released on 2003 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Elucidation of the Factors Responsible for Small Solute Retention and Irreversible Protein Binding in Reversed phase High Performance Liquid Chromatography written by Paul Charles Sadek and published by . This book was released on 1985 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt:
