Optimization of Chromatographic Selectivity


Book Description

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.










Selectivity and Detectability Optimizations in HPLC


Book Description

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.




HPLC Made to Measure


Book Description

The only topical HPLC book to focus on optimization, this volume addresses the needs of HPLC users who wish to constantly improve their methods, in particular in terms of throughput, accuracy and cost-effectiveness. This handbook features contributions from such bestselling authors as John W. Dolan, Michael McBrien, Veronika R. Meyer, Uwe D. Neue, Lloyd R. Snyder, and Klaus K. Unger, as well as from scientists working for major companies, including Agilent, AstraZeneca, Merck, Schering, Tosoh Biosep, VWR, and Waters. It covers essential aspects of optimization in general, optimization in different LC-modi, hyphenated techniques and computer-aided optimization. The whole is rounded off with a section of user reports.




Retention and Selectivity in Liquid Chromatography


Book Description

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.




Optimization in HPLC


Book Description

Learn to maximize the performance of your HPLC or UHPLC system with this resource from leading experts in the field Optimization in HPLC: Concepts and Strategies delivers tried-and-tested strategies for optimizing the performance of HPLC and UHPLC systems for a wide variety of analytical tasks. The book explains how to optimize the different HPLC operation modes for a range of analyses, including small molecules, chiral substances, and biomolecules. It also shows readers when and how computational tools may be used to optimize performance. The practice-oriented text describes common challenges faced by users and developers of HPLC and UHPLC systems, as well as how those challenges can be overcome. Written for first-time and experienced users of HPLC technology and keeping pace with recent developments in HPLC instrumentation and operation modes, this comprehensive guide leaves few questions unanswered. Readers will also benefit from the inclusion of: A thorough introduction to optimization strategies for different modes and uses of HPLC, including working under regulatory constraints An exploration of computer aided HPLC optimization, including ChromSwordAuto and Fusion QbD A treatment of current challenges for HPLC users in industry as well as large and small analytical service providers Discussions of current challenges for HPLC equipment suppliers Tailor-made for analytical chemists, chromatographers, pharmacologists, toxicologists, and lab technicians, Optimization in HPLC: Concepts and Strategies will also earn a place on the shelves of analytical laboratories in academia and industry who seek a one-stop reference for optimizing the performance of HPLC systems.




High Performance Liquid Chromatography


Book Description

High Performance Liquid Chromatography focuses on the developments, operating techniques, practices, equipment, and packing materials involved in High Performance Liquid Chromatography (HPLC). The book first offers information on basic chromatographic theory, equipment, and the column. Topics include resolution, efficiency, pumps and gradient systems, connectors, detectors, injectors, column packing and testing, packing materials, and coupling of columns. The text also ponders on sample treatment and separation methods, as well as trace analysis, reversed phase chromatography, and selection/optimization conditions. The publication examines adjustment of selectivity by the use of eluent additives and preparative liquid chromatography. Discussions focus on chromatography on dynamically modified oxide gels, metal complexation, crown ethers, ion pair chromatography, materials for preparative chromatography, and separation strategy. The text also reviews the trends in the practice of HPLC and chiral chromatography. The book is a dependable reference for readers interested in High Performance Liquid Chromatography.




Liquid Chromatography


Book Description

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.




Scale-Up and Optimization in Preparative Chromatography


Book Description

Presenting guidelines to predict and improve separation system performance, this book contains numerous case studies illustrating the practice of scale-up principles in process development. It offers solutions to limitations that occur in real-world purification schemes; methods to model, optimize, and characterize nonlinear separation processes; d