Download or read book A Thermodynamic Investigation of Retention and Selectivity in Reversed phase Liquid Chromatographic Systems written by Bhajendra Narayan Barman and published by . This book was released on 1985 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Part I A Thermodynamic Study of Acetonitrile Water Mixtures in Reversed Phase Liquid Chromatography Part II A Gas Chromatographic Study of the Effect of Temperature and Column Pressure on Solute Retention on a Bonded Phase Using Helium and Carbon Dioxide as Mobile Phases written by Aurelio Alvarez-Zepeda and published by . This book was released on 1991 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Advances in Chromatography written by Eli Grushka and published by CRC Press. This book was released on 2009-12-23 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: For more than four 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. With contributions from an array of international experts, the latest volume captures new developments in this important field th

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 High Temperature Liquid Chromatography written by Thorsten Teutenberg and published by Royal Society of Chemistry. This book was released on 2010-06-03 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-temperature liquid chromatography has attracted much interest in recent years but has not yet recognized its full potential in the chromatographic community. There is a widespread reluctance in industry to use temperature to speed up the separation process, influence the selectivity of a separation or implement novel detection techniques. However, the technology has now matured and could revolutionize chromatography as we see it today. Better equipment, such as heating systems able to generate faster heating rates, is becoming more readily available. Also, columns based on silica gel, which can withstand higher temperatures for an extended period, are now being introduced. Nevertheless, further technological and methodical efforts are needed to establish the method in a regulated environment like the pharmaceutical industry. This is the only text to cover all the practical aspects, as well as the underlying theoretical principles, of setting up an HPLC system for high temperature operation. It is not intended solely for academics but will also benefit the researcher interested in more practical considerations. The author is a recognized expert and has conducted several studies with partners from industry to validate the method. Many real examples from these studies have been included in the book. The aim is to support practitioners in the creation of their own protocols without the need to rely solely on trial and error. The book starts with a brief definition of high temperature liquid chromatography before going on to cover: system set up; the heating system; mobile phase considerations; suitable stationary phases; method development using temperature programming; analyte stability, and special hyphenation techniques using superheated water as a mobile phase. In each chapter, experimental data is used to illustrate the main statements and the advantages over conventional HPLC are evaluated. The book concludes with a critical outlook on further developments and applications underlining the necessary advances needed to make high temperature HPLC more robust.

Download or read book Investigation of Retention Mechanisms in Reversed phase Liquid Chromatography with Reaction Kinetics written by Brian Scott Ludolph and published by . This book was released on 1989 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optimization of Chromatographic Selectivity written by P.J. Schoenmakers and published by Elsevier. This book was released on 1986-08-01 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first detailed description of method development in chromatography - the overall process of which may be summarized as: method selection, phase selection, selectivity optimization, and system optimization. All four aspects receive attention in this book.Chapter 1 gives a short introduction, describes chromatographic theory and nomenclature, and outlines the method development process. Chapter 2 describes guidelines for method selection, and quantitative concepts for characterizing and classifying chromatographic phases. Selective separation methods, from both gas and liquid chromatography are given in Chapter 3; the main parameters of each method are identified and simple, quantitative relations are sought to describe their effects. Criteria by which to judge the quality of separation are discussed in Chapter 4 with clear recommendations for different situations. The specific problems involved in the optimization of chromatographic selectivity are explained in Chapter 5. Optimization procedures, illustrated by examples, are extensively described and compared on the basis of a number of criteria. Suggestions are made both for the application of different procedures and for further research. The optimization of programmed analysis receives special attention in Chapter 6, and the last chapter summarizes the optimization of the chromatographic system, including the optimization of the efficiency, sensitivity and instrumentation.Those involved in developing chromatographic methods or wishing to improve existing methods will value the detailed, structured way in which the subject is presented. Because optimization procedures and criteria are described as elements of a complete optimization package, the book will help the reader to understand, evaluate and select current and future commercial systems.

Download or read book High Performance Gradient Elution written by Lloyd R. Snyder and published by John Wiley & Sons. This book was released on 2007-01-09 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gradient elution demystified Of the various ways in which chromatography is applied today, few have been as misunderstood as the technique of gradient elution, which presents many challenges compared to isocratic separation. When properly explained, however, gradient elution can be less difficult to understand and much easier to use than often assumed. Written by two well-known authorities in liquid chromatography, High-Performance Gradient Elution: The Practical Application of the Linear-Solvent-Strength Model takes the mystery out of the practice of gradient elution and helps remove barriers to the practical application of this important separation technique. The book presents a systematic approach to the current understanding of gradient elution, describing theory, methodology, and applications across many of the fields that use liquid chromatography as a primary analytical tool. This up-to-date, practical, and comprehensive treatment of gradient elution: * Provides specific, step-by-step recommendations for developing a gradient separation for any sample * Describes the best approach for troubleshooting problems with gradient methods * Guides the reader on the equipment used for gradient elution * Lists which conditions should be varied first during method development, and explains how to interpret scouting gradients * Explains how to avoid problems in transferring gradient methods With a focus on the use of linear solvent strength (LSS) theory for predicting gradient LC behavior and separations by reversed-phase HPLC, High-Performance Gradient Elution gives every chromatographer access to this useful tool.

Download or read book Structure and Retention in Chromatography written by Kaliszan and published by CRC Press. This book was released on 1997-05-22 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an update on the basics, trends and achievements of chemometric methodology required to study the relation between the chemical structure of solutes and their retention in various chromatographic systems. The author critically analyzes hundreds of relevant papers published during the past two decades. In this period, chemometrics has evolved into an established research and practice area of interest to scientists ranging from chromatographers to environmental and medicinal chemists. Although emphasis is placed on the more recent findings, readers will also find the basic theories required to solve specific problems. It should prove advantageous for contemporary chemists and related scientists if they switch from thermodynamics - in practice often inappropriate - to a statistically based (and limited) chemometric approach.

Download or read book Liquid Chromatography written by M.C. García-Álvarez-Coque and published by Elsevier Inc. Chapters. This book was released on 2013-01-08 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: The addition of reagents to an RPLC mobile phase enables the separation of ionizable compounds, inorganic anions, and metal ions using conventional instrumentation, silica-based materials, and hydro-organic mixtures, thanks to a variety of secondary equilibria. This gives rise to several chromatographic modes, whose main features are outlined in this chapter. The effect of the mobile phase pH on the retention of ionizable compounds is described, together with the recommended experimental practice. The mechanism of adsorption of amphiphilic anions or cations on the stationary phase to attract analytes with opposite charge or suppress the silanol activity is discussed. Different reagents, such as alkylammonium salts, surfactants (below and above the critical micelle concentration), perfluorinated carboxylate anions, chaotropic ions, and ionic liquids, are considered. The potential of metal chelation for the determination of metal ions and organic compounds is also summarized.

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 High Performance Liquid Chromatography written by Csaba Horváth and published by Elsevier. This book was released on 2013-10-22 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-Performance Liquid Chromatography: Advances and Perspectives, Volume 4 is an authoritative publication that deals with the fundamentals, instrumentation, and applications of high-performance liquid chromatography. The volume contains articles on practical aspects of reversed-phase chromatography in the study of biopolymer separations; characterization of stationary phases and the development of various packing materials; electrochemical detection; and the fundamentals of chromatographic behavior of large molecules. Chromatographers, chemists, and researchers in the field of chemical analysis will find this book an interesting read.

Download or read book Liquid Chromatography written by G. Ramis-Ramos and published by Elsevier Inc. Chapters. This book was released on 2013-01-08 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many solvents can be used to prepare mobile phases in liquid chromatography. Also, mixtures of solvents at different ratios are used to modify the mobile phase properties. This can make solvent selection for method development a hard task, unless suitable guidelines are followed. This chapter summarizes the most common strategies used by skilled chromatographists in reversed-phase, normal-phase, and hydrophilic interaction liquid chromatography. These are based on considerations about the global polarity of solutes, stationary phase and mobile phase, which determine the elution strength, and on the particular profile of the contributions of intermolecular interactions to the global polarity, which determines the selectivity. The optimization of selectivity using isoeluotropic mixtures on the rational basis provided by solvent selectivity triangles and systematic trial-and-error procedures in the isocratic and gradient elution modes is described. Additional considerations for mobile-phase selection, including computer-assisted interpretive optimization, sustainability criteria, and the use of high temperatures, are also commented.

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 Studies on Reversed phase Ion pair Chromatography with a Dynamically Coated Adsorbent written by Monika Johansson and published by . This book was released on 1981 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: