Retention And Selectivity In Liquid Chromatography

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.

The latest edition of the authoritative reference to HPLC High-performance liquid chromatography (HPLC) is today the leading technique for chemical analysis and related applications, with an ability to separate, analyze, and/or purify virtually any sample. Snyder and Kirkland's Introduction to Modern Liquid Chromatography has long represented the premier reference to HPLC. This Third Edition, with John Dolan as added coauthor, addresses important improvements in columns and equipment, as well as major advances in our understanding of HPLC separation, our ability to solve problems that were troublesome in the past, and the application of HPLC for new kinds of samples. This carefully considered Third Edition maintains the strengths of the previous edition while significantly modifying its organization in light of recent research and experience. The text begins by introducing the reader to HPLC, its use in relation to other modern separation techniques, and its history, then leads into such specific topics as: The basis of HPLC separation and the general effects of different experimental conditions Equipment and detection The column—the "heart" of the HPLC system Reversed-phase separation, normal-phase chromatography, gradient elution, two-dimensional separation, and other techniques Computer simulation, qualitative and quantitative analysis, and method validation and quality control The separation of large molecules, including both biological and synthetic polymers Chiral separations, preparative separations, and sample preparation Systematic development of HPLC separations—new to this edition Troubleshooting tricks, techniques, and case studies for both equipment and chromatograms Designed to fulfill the needs of the full range of HPLC users, from novices to experts, Introduction to Modern Liquid Chromatography, Third Edition offers the most up-to-date, comprehensive, and accessible survey of HPLC methods and applications available.

High-Performance Liquid Chromatography: Advances and Perspectives, Volume 1 deals with the fundamental aspects of high-performance liquid chromatography, a technique used in chemical analysis. The publication provides accounts, presented by experts in the field, of a variety of topics in high-performance liquid chromatography. Each chapter covers interesting subjects such as the evolution of liquid chromatography; the use of bonded phases in high-performance chromatography; effects of ionization and complex formation on retention and selectivity in reversed-phase chromatography; and gradient elution. Chromatographers, chemists, and researchers in the field of chemical analysis will find this book a valuable reference material.

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.

High performance liquid chromatography (HPLC) has long been recognized as one of the most useful and versatile analytical techniques. It has now progressed from being a highly expensive method of analysis to a routine technique with wide applications. Consequently there is a requirement in many chemistry and chemistry-related courses for students to acquire a detailed understanding of the principles and practice of HPLC. Written in a manner suitable for undergraduate students studying analytical chemistry and learning about chromatographic analytical techniques applied to pharmaceutical analysis, biochemistry and related disciplines, High-performance Liquid Chromatography: Fundamental Principles and Practice introduces the fundamentals of HPLC. Loosely structured in three parts, the text begins with a thorough introduction of the subject and then progresses through the essential knowledge of the instrumentation needed for HPLC. The final part covers with the applications of HPLC in real-world situations. Developed by a team of international experts from a wide cross-section of disciplines, the text is relevant to a wide range of courses.

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.

'The book is a useful contribution in the field of HPLC, and may represent a valuable tool for chromatography practitioners in different fields, as well as teachers and instructors. The 12 chapters provide comprehensive insights of current day retention and resolution modelling in HPLC, and its applications for small and large molecule analysis. It may be a useful reference for specialists in pharmaceuticals but not limited to … It may be a valuable resource to assist scientists involved in method development, aiming to achieve the best results with reduced costs, time, and efforts.'Analytical and Bioanalytical ChemistryThis handbook gives a general overview of the possibilities in recent developments in chromatographic retention modeling. As a result of the latest developments in modeling software, several new features are now accessible, opening a new level in HPLC method development.Many of these current possibilities in software assisted liquid chromatographic method modeling for analytical purposes are presented. Several modes of chromatography, including Reversed-Phase Liquid Chromatography (RPLC), Ion Exchange Chromatography (IEX), Hydrophobic Interaction Chromatography (HIC), and Hydrophilic Interaction Liquid Chromatography (HILIC) are explained in detail. For all these chromatographic modes, the most important variables for tuning retention and selectivity are exposed.Beside the industrial and practical benefits of retention modeling, the possibilities in teaching and education are also illustrated. Finally, numerous representative industrial examples are shown, to highlight the benefits, time and cost savings offered by state-of-the-art software assisted HPLC method development.

High Performance Liquid Chromatography Edited by Phyllis Brown and Richard Hartwick This contributed volume is designed to consolidate the basic theories of chromatography along with the more exciting developments in the field. This monograph addresses some questions that concern researchers in separation science, including: what is the current state of the art in liquid chromatography; has the development of liquid chromatography plateaued; if so, what new methods will take its place or complement it; and if not, where will the new frontiers be and what direction will liquid chromatography take? 1989 (0 471-84506-X) 688 pp. Quantitative Structure-Chromatographic Retention Relationships R. Kaliszan Written by a pioneer in the field, this book extends and updates research on quantitative structure retention relationships by consolidating and critically reviewing the extensive literature on the subject, while also providing the basic theoretical and practical information required in all investigations involving chromatography, analytical chemistry, biochemistry, and pharmaceutical research. Among the topics covered are the nature of chromatographic interactions, molecular interpretation of distribution processes in chromatography, topological indices as retention descriptors, and multiparameter structure-chromatographic retention relationships. 1987 (0 471-85983-4) 303 pp. Detectors for Liquid Chromatography Edited by Edward S. Yeung With its singular coverage of this fast-growing field, Detectors for Liquid Chromatography presents the state of the art in this subject area. It offers a comprehensive examination of the basic principles behind the detector response, instrumentation, and selected applications for comparison and evaluation of potential. Specifically, topics given in-depth coverage include polarimetric, indirect absorbance, refractive index detectors, absorption detectors for HPLC, FTIR and fluorometric detection, detection based on electrical and electromechanical measurements, and mass spectroscopy as an on-line detector for HPLC. 1986 (0 471-82169-1) 366 pp.