Download or read book Exploring the Retention Characteristics of Stationary Phases and Their Application in Two dimensional High Performance Liquid Chromatography written by Paul G. Stevenson and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Phenyl type stationary phases have the ability to undergo [pi]-[pi] interactions with aromatic compounds and have the potential to take advantage of this particular sample dimension in 2DHPLC. This thesis examined a series of phenyl type stationary phases that were synthesised and packed in-house, containing systematic changes in the length of the chain binding the aromatic ring to the silica support (between 0 and 4 carbon atoms). The stationary phase was characterised and tested to determine retention characteristics with both linear and non-linear chromatographic measurements. The linear measurements involved a selectivity study with homologues of linear polycyclic aromatic hydrocarbons and n-alkylbenzenes to determine the aromatic and methylene selectivities, respectively.

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 Essentials in Modern HPLC Separations written by Serban C. Moldoveanu and published by Elsevier. This book was released on 2022-06-24 with total page 718 pages. Available in PDF, EPUB and Kindle. Book excerpt: Essentials in Modern HPLC Separations, Second Edition discusses the role of separation in high performance liquid chromatography (HPLC). This new and updated edition systematically presents basic concepts as well as new developments in HPLC. Starting with a description of basic concepts, it provides important guidance for the practical utilization of various HPLC procedures, such as the selection of the HPLC type, proper choice of the chromatographic column, selection of mobile phase and selection of the method of detection, all of which are in correlation with the physico-chemical characteristics of the compounds separated. Every chapter has been carefully reviewed, with several new sections added to bring the book completely up-to-date. Hence, it is a valuable reference for students and professors in chemistry. Provides a thoroughly updated resource, with an entirely new section on Computer-aided Method Development in HPLC and new subsections on miniaturization and automation in HPLC, chemometric aspects of HPLC, green solvent use in HPLC, and more Includes insights into the chromatographic process to find the optimum solution for analyzing complex samples Presents a basis for understanding the utilization of modern HPLC for applications, particularly for the analysis of pharmaceutical, biological, food, beverage and environmental samples

Download or read book Development of New Stationary Phases and Their Applications in High Performance Liquid Chromatography written by Haixiao Qiu and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: High performance liquid chromatography (HPLC) has proven to be the most widely applicable and versatile technique in separation science. Hydrophilic interaction liquid chromatography (HILIC) has attracted considerable interest and has become a viable option for the separation of polar compounds. Chirality is another major concern in the modern pharmaceutical industry for two reasons: 1). the majority of bio-organic molecules are chiral; 2). enantiomers of a racemic drug may often exhibit different biological activities, pharmacokinetics, and toxicities. The field of enantiomeric separations has reached a clear level of maturity after approximately 30 years of development. However, with the continued emphasis on stereochemistry in drug design and development, chiral separations are in ever increasing demand. The development of new, more effective methods is still challenging and demanding experimentally. This dissertation discusses new research in three areas: 1). Development and application of new HILIC stationary phases for the separation of polar organic compounds. Two types of new HILIC stationary phases have been successfully synthesized and evaluted. One is based on native cyclofructan 6 and another one is a zwitterionic stationary phase based on 3-P,P-diphenylphosphonium-propylsulfonate. Their performance and retention mechanisms in the HILIC mode will be discussed in this dissertation.2). Development and evaluation of new chiral stationary phases. R-naphthylethyl-carbamate cyclofructan 6 (RN-CF6) and dimethylphenyl-carbamate cyclofructan 7 (DMP-CF7) were successfully synthesized and provide enantioselectivity toward a broad range of chiral compounds. They were found to be the best aromatic-functionalized cyclofructan chiral stationary phases and provide enantiomeric separations complementary to the isopropyl-carbamate cyclofructan 6 based chiral stationary phase. This dissertation also describes method development of enantiomeric impurities quantification in chiral reagents. Three macrocyclic chiral stationary phases, including cyclodextrins, macrocyclic glycopeptides and cyclofructans, have been used to determine enantiomeric impurities in new chiral catalysts, auxiliaries and synthons used in asymmetric syntheses. It was found that many of the newer chiral reagents are highly enantiopure, probably due to continual improvements in asymmetric syntheses and purification in the manufacturing process. 3). Development and application of new stationary phases based on a resin substrate instead of silica gel. This dissertation describes methods for binding cyclofructan 6 to resin via "click" chemistry. It was found that these resin based stationary phases appear to have potential in HILIC separations (native cyclofructan 6 bonded to resin as stationary phases) and enantiomeric separations (isopropyl-carbamated cyclofructan 6 bonded to resin).

Download or read book Green Analytical Chemistry 2nd Edition written by Mihkel Koel and published by Royal Society of Chemistry. This book was released on 2019-03-13 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical analysis requires solvents, reagents and energy and generates waste. The main goal of green analytical chemistry is to avoid or reduce the undesirable environmental side effects of chemical analysis, while preserving the classic analytical parameters of accuracy, sensitivity, selectivity and precision. This book portrays the current and changing situation concerning adoption of the principles of green chemistry as applied to analysis. It begins by looking at the advantages of and problems associated with on-site analysis and how analytical techniques can lead to increased productivity, efficiency and accuracy, and thereby reduce the consumption of materials. It then focuses on sample preparation techniques minimising solvent consumption or using alternative solvents, concepts and methods of improving the ‘greenness’ of instrumental analysis where miniaturization is an important part, separation methods from the perspective of green analytical chemistry and chemometrics approaches, which can reduce or can even remove the need for conventional steps in chemical analysis. Aimed at graduates and novices just entering the field, managers of analytical research laboratories, teachers of analytical chemistry and green public policy makers, this title will be a useful addition to any analytical scientist's library.

Download or read book Exploration in Analytical Separations Using High Performance Liquid Chromatography written by Yaqin Sun and published by . This book was released on 2006 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unique solvation properties of ionic liquids (ILs) are being used to advantage in the dissolution of a wide range of organic and inorganic substances, including both neutral and charged species. Investigations of the physicochemical properties of ILs and solute/stationary-phase interactions in GC suggest that ILs may be useful as multimodal media in chromatographic separations. In this work, a butylimidazolium cation with a Br- counter-ion was immobilized on porous silica particles and examined as a stationary phase for LC. In chromatography, the LSER methodology has been used to correlate retention with fundamental solute/mobile-phase and solute/stationary-phase properties. The present study has established a relationship between the system constants and properties of an IL-type stationary phase by the LSER approach. It focuses on characterizing solute retention using methanol-water and acetonitrile-water binary mobile phases. Results are discussed in terms of the chemical meaning of the magnitude of the coefficient as well as its sign and the effect of mobile-phase composition. These results and further comparisons with conventional systems confirm the presence of the hydrophobic retention property and the importance of the ion-dipole/dipole-dipole retention mechanism for two stationary phases (the butylimidazolium-based and a commercial anion exchange). The impact of organic modifiers on separation of selected compounds is also discussed. In addition, the primary results of the LSER extension for modeling retentions of some ionizable compounds, as well as error propagations in retention, are presented. The preliminary application of IL-based stationary phase on polyphenol separation will be examined.

Download or read book Handbook of Trace Analysis written by Irena Baranowska and published by Springer. This book was released on 2015-08-13 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook is unique in its comprehensive coverage of the subject and focus on practical applications in diverse fields. It includes methods for sample preparation, the role of certified reference materials, calibration methods and statistical evaluation of the results. Problems concerning inorganic and bioinorganic speciation analysis, as well as special aspects such as trace analysis of noble metals, radionuclides and volatile organic compounds are also discussed. A significant part of the content presents applications of methods and procedures in medicine (metabolomics and therapeutic drug monitoring); pharmacy (the analysis of contaminants in drugs); studies of environmental samples; food samples and forensic analytics – essential examples that will also facilitate problem solving in related areas.

Download or read book Advances in Chromatography Volume 57 written by Nelu Grinberg and published by CRC Press. This book was released on 2020-08-05 with total page 219 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. 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. This volume considers the achievements and legacy of Lloyd R. Snider in separation science and analytical chemistry. Key Features: • Provides a historical perspective of the evolution of SMB technology together with a theoretical analysis of the most relevant underlying phenomena. • Presents a brief survey of the polar columns suitable for HILIC separations and pays special attention to the role of the mobile phase in RP and HILIC modes. • Describes recent strategies of method development in Kosmotropic chromatography. • Surveys the many approaches to avert the effects of temperature in reversed-phase liquid chromatographic separations. • Reviews separation of isotopic compounds by HPLC in relation to the advances of columns and stationary phases.

Download or read book Nanoanalytics written by Sergei Shtykov and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-03-19 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoanalytics is a novel branch of analytical chemistry which explores applications of nanotechnologies in chemical analysis. This comprehensive publication gives an overview of the analytical techniques used to study nanoobjects and nanoparticles as well as the application of nanomaterials themselves in the development of new methods of analysis. The authors also address important metrology aspects and give future prospects of the area.

Download or read book Comparison of the Retention Properties of Two Stationary Phases for Use in Reversed phase Liquid Chromatography written by Mary Lisa Belvito and published by . This book was released on 1987 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Postdoctoral Research Associateships written by and published by . This book was released on 1982 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Chromatography written by Eli Grushka and published by CRC Press. This book was released on 2006-10-25 with total page 296 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. Volume 45 of this authoritative series once again compiles the work of expert contributors in order to present timely and cutting

Download or read book A Century of Separation Science written by Haleem J. Issaq and published by CRC Press. This book was released on 2001-12-19 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Century of Separation Science presents an extensive overview of the critical developments in separation science since 1900, covering recent advances in chromatography, electrophoresis, field-flow fractionation, countercurrent chromatography, and supercritical fluid chromatography for high-speed and high-throughput analysis.

Download or read book Tietz Textbook of Clinical Chemistry and Molecular Diagnostics written by Nader Rifai and published by Elsevier Health Sciences. This book was released on 2017-01-16 with total page 1888 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Tietz Textbook of Clinical Chemistry and Molecular Diagnostics, 6th Edition provides the most current and authoritative guidance on selecting, performing, and evaluating the results of new and established laboratory tests. This classic clinical chemistry reference offers encyclopedic coverage detailing everything you need to know, including: analytical criteria for the medical usefulness of laboratory tests, variables that affect tests and results, laboratory medicine, applications of statistical methods, and most importantly clinical utility and interpretation of laboratory tests. It is THE definitive reference in clinical chemistry and molecular diagnostics, now fully searchable and with quarterly content updates, podcasts, clinical cases, animations, and extended content online through Expert Consult. Analytical criteria focus on the medical usefulness of laboratory procedures. Reference ranges show new approaches for establishing these ranges — and provide the latest information on this topic. Lab management and costs gives students and chemists the practical information they need to assess costs, allowing them to do their job more efficiently and effectively. Statistical methods coverage provides you with information critical to the practice of clinical chemistry. Internationally recognized chapter authors are considered among the best in their field. Two-color design highlights important features, illustrations, and content to help you find information easier and faster. NEW! Internationally recognized chapter authors are considered among the best in their field. NEW! Expert Consult features fully searchable text, quarterly content updates, clinical case studies, animations, podcasts, atlases, biochemical calculations, multiple-choice questions, links to Medline, an image collection, and audio interviews. You will now enjoy an online version making utility of this book even greater. UPDATED! Expanded Molecular Diagnostics section with 12 chapters that focus on emerging issues and techniques in the rapidly evolving and important field of molecular diagnostics and genetics ensures this text is on the cutting edge and of the most value. NEW! Comprehensive list of Reference Intervals for children and adults with graphic displays developed using contemporary instrumentation. NEW! Standard and international units of measure make this text appropriate for any user — anywhere in the world. NEW! 22 new chapters that focus on applications of mass spectrometry, hematology, transfusion medicine, microbiology, biobanking, biomarker utility in the pharmaceutical industry and more! NEW! Expert senior editors, Nader Rifai, Carl Wittwer and Rita Horvath, bring fresh perspectives and help ensure the most current information is presented. UPDATED! Thoroughly revised and peer-reviewed chapters provide you with the most current information possible.

Download or read book Cumulated Index Medicus written by and published by . This book was released on 2000 with total page 1836 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Handbook of Thin Layer Chromatography written by Joseph Sherma and published by CRC Press. This book was released on 2003-04-18 with total page 1356 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this third edition, more than 40 renowned authorities introduce and update chapters on the theory, fundamentals, techniques, and instrumentation of thin-layer chromatography (TLC) and high-performance thin-layer chromatography (HPTLC), highlighting the latest procedures and applications of TLC to 19 important compound classes and coverage of TLC applications by compound type. Easily adaptable to industrial scenarios , the Handbook of Thin-Layer Chromatography, Third Edition supports practical research strategies with extensive tables of data, offers numerous figures that illustrate techniques and chromatograms, and includes a glossary as well as a directory of equipment suppliers.

Download or read book Handbook of Affinity Chromatography written by David S. Hage and published by CRC Press. This book was released on 2005-07-19 with total page 878 pages. Available in PDF, EPUB and Kindle. Book excerpt: This essential handbook guides investigators in the theory, applications, and practical use of affinity chromatography in a variety of fields including biotechnology, biochemistry, molecular biology, analytical chemistry, proteomics, pharmaceutical science, environmental analysis, and clinical chemistry. The Handbook of Affinity Chromatograph