Download or read book The Distribution of Organic Bases in Reverse Phase Liquid Chromatography written by Dudley Shelton Jayasinghe and published by . This book was released on 1989 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: The distribution of hydrophobic ionogenic organic compounds (HIOC's) between aqueous and nonaqueous phases has been investigated. The HIOC's are aniline and methyl substituted anilines. The aqueous phases are methanol-water mixed solvents with varying pH and ionic strength. The nonaqueous phases are silica and alkyl derivatized silica with ethyl- (C-2), octyl- (C-8), and octadecyl- (C-18) silanes. A gas-liquid equilibration method has been developed to determine the Henry's law constants and the activity coefficients of methyl anilines in methanol-water mixed solvents. The logarithm of the Henry's law constants vary quadratically with the volume fraction of methanol. The chromatographic study has been performed to investigate the effect of three mobile phase factors, fraction of methanol, pH, and ionic strength, on the retention of methyl anilines on different stationary phases. The logarithm of mass distribution ratios, log k's, of methyl anilines vary linearly with the volume fraction of methanol. The ratios of H / k' of methyl anilines increase with increase in methanol in the mobile phase, indicating an increase in the activity coefficients in the stationary phases. This observation is found to be true for different methyl anilines in different stationary phases. A partition model is presented to describe the effect of pH and ionic strength on the retention of HIOC's in the mobile phase. The variation in log k' among neutral and ionic methyl anilines can be explained by linear free energy relationships. Equations are established to predict retention of neutral or ionized methyl anilines from their octanol-water partition coefficients at any methanol content in the mobile phase. Acid dissociation constants of methyl anilines determined from the dependence of log k' on pH are in close agrement with those determined by potentiometric titrations. The effect of ionic strength on the retention of both neutral and ionic species of methyl anilines is negligible. That is, the contribution from electrostatic energy and salting out effect are not significant. The chromatographic study is extended to study the retention of methyl anilines on silica as a function of pH and methanol at a constant ionic strength. The dependence of retention on pH is qualitatively interpreted from an ion exchange reaction between the dissociated silanol groups in the surface and the ionized methyl anilines. The effect of methanol on the retention of methyl anilines and of pyridine on silica is described by a quadratic relationship between the log k' and volume fraction of methanol.

Download or read book Separation Methods in Drug Synthesis and Purification written by Klara Valko and published by Elsevier. This book was released on 2000-10-13 with total page 613 pages. Available in PDF, EPUB and Kindle. Book excerpt: Separation Methods in Drug Synthesis and Purification

Download or read book High performance liquid chromatography of organic acids using l written by Catherina Paulina Terweij-groen and published by . This book was released on 19?? with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Methylene Selectivity of Simple Organic Ions in Reversed phase Liquid Chromatography written by Dongmei Wu and published by . This book was released on 1992 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Reversed phase Liquid Chromatography of Nucleotides Nucleosides and Bases Theoretical and Clinical Aspects written by Mona Zakaria and published by . This book was released on 1981 with total page 388 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:

Download or read book Medical Applications of Mass Spectrometry written by Karoly Vekey and published by Elsevier. This book was released on 2011-08-11 with total page 607 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mass spectrometry is fast becoming an indispensable field for medical professionals. The mass spectrometric analysis of metabolites and proteins promises to revolutionize medical research and clinical diagnostics. As this technology rapidly enters the medical field, practicing professionals and students need to prepare to take full advantage of its capabilities. Medical Applications of Mass Spectrometry addresses the key issues in the medical applications of mass spectrometry at the level appropriate for the intended readership. It will go a long way to help the utilization of mass spectrometry in medicine.The book comprises five parts. A general overview is followed by a description of the basic sampling and separation methods in analytical chemistry. In the second part a solid foundation in mass spectrometry and modern techniques of data analysis is presented. The third part explains how mass spectrometry is used in exploring various classes of biomolecules, including proteins and lipids. In the fourth section mass spectrometry is introduced as a diagnostic tool in clinical treatment, infectious pathogen research, neonatal diagnostics, cancer, brain and allergy research, as well as in various fields of medicine: cardiology, pulmonology, neurology, psychiatric diseases, hemato-oncology, urologic diseases, gastrointestinal diseases, gynecology and pediatrics. The fifth part covers emerging applications in biomarker discovery and in mass spectrometric imaging. * Provides a broad look at how the medical field is benefiting from advances in mass spectrometry.* Guides the reader from basic principles and methods to cutting edge applications.* There is NO comparable book on the market to fill this fast growing field.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 1992 with total page 850 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proteomic Profiling and Analytical Chemistry written by Pawel Ciborowski and published by Elsevier. This book was released on 2016-03-02 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proteomic Profiling and Analytical Chemistry: The Crossroads, Second Edition helps scientists without a strong background in analytical chemistry to understand principles of the multistep proteomic experiment necessary for its successful completion. It also helps researchers who do have an analytical chemistry background to break into the proteomics field. Highlighting points of junction between proteomics and analytical chemistry, this resource links experimental design with analytical measurements, data analysis, and quality control. This targeted point of view will help both biologists and chemists to better understand all components of a complex proteomic study. The book provides detailed coverage of experimental aspects such as sample preparation, protein extraction and precipitation, gel electrophoresis, microarrays, dynamics of fluorescent dyes, and more. The key feature of this book is a direct link between multistep proteomic strategy and quality control routinely applied in analytical chemistry. This second edition features a new chapter on SWATH-MS, substantial updates to all chapters, including proteomic database search and analytical quantification, expanded discussion of post-hoc statistical tests, and additional content on validation in proteomics. Covers the analytical consequences of protein and peptide modifications that may have a profound effect on how and what researchers actually measure Includes practical examples illustrating the importance of problems in quantitation and validation of biomarkers Helps in designing and executing proteomic experiments with sound analytics

Download or read book American Doctoral Dissertations written by and published by . This book was released on 1989 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Purification of Laboratory Chemicals written by W.L.F. Armarego and published by Elsevier. This book was released on 2003-03-07 with total page 627 pages. Available in PDF, EPUB and Kindle. Book excerpt: Now in its fifth edition, the book has been updated to include more detailed descriptions of new or more commonly used techniques since the last edition as well as remove those that are no longer used, procedures which have been developed recently, ionization constants (pKa values) and also more detail about the trivial names of compounds.In addition to having two general chapters on purification procedures, this book provides details of the physical properties and purification procedures, taken from literature, of a very extensive number of organic, inorganic and biochemical compounds which are commercially available. This is the only complete source that covers the purification of laboratory chemicals that are commercially available in this manner and format. * Complete update of this valuable, well-known reference* Provides purification procedures of commercially available chemicals and biochemicals* Includes an extremely useful compilation of ionisation constants

Download or read book Groundwater Chemicals Desk Reference written by John H. Montgomery and published by CRC Press. This book was released on 2007-04-18 with total page 2489 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using a clear and consistent format, this fourth edition contains more than 1,700 additional references and additional adsorption data for more than 800 organic compounds and metals, Henry's Law constants for 1,850 compounds, aqueous solubility data for over 2,500 compounds, toxicity data for 1,100 compounds, more than 31,000 synonyms, and 2,224 degradation products cross-referenced to parent compounds. Additional organic and inorganic solubilities, conversion factors, octanol-water partition coefficients, environmental fate data, analytical test methods, dielectric properties of various materials and liquids, and other tables and indexes have been added along with references for numerous physical parameters.

Download or read book The Essence of Chromatography written by C. F. Poole and published by Elsevier. This book was released on 2003 with total page 940 pages. Available in PDF, EPUB and Kindle. Book excerpt: General concepts in column chromatography -- The column in gas chromatography -- Instrumental aspects of gas chromatography -- The column in liquid chromatography -- Instrumental aspects of liquid chromatography -- Thin-layer chromatography -- Supercritical fluid chromatography -- Capillary-electromigration separation techniques -- Spectroscopic detectors for identification and quantification -- Separation of stereoisomers -- Laboratory-scale preparative chromatography.

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 Prediction of the Environmental Fate of Chemicals written by Y. Samiullah and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concern over the effects of chemicals in the environment has been increasing for many years. Environmental contamination by DDT, Aldrin, Dieldrin, mercury, PCBs, organotins and many other sub stances are all part of the public consciousness and have led to widespread attention to this topic. Some of the concerns have arisen because human health has been affected when contaminants have been consumed via the food chain-for instance in the case of 'Minimata disease' in Japan. In other cases, direct effects on other components of ecosystems have given cause for alarm. The toxic effects which any chemical can cause are a function of exposure and innate toxicity, i.e. of the ability to reach in sufficient quantity a site where a biological process can be disrupted and of the tendency to cause disruption when it gets there. The processes by which chemicals reach sites of toxic action are the subject of this book, and are a fundamental consideration in ecotoxi cology. When a chemical enters the environment e.g. via a spillage or in an effluent, it is potentially subject to a wide variety of processes which may eliminate it from the environment completely, modify it into a more or less harmful substance, or transfer it to another part of the environment. The processes involved are complex and highly variable, but it is essential to increase our understanding of them.

Download or read book Liquid Chromatography written by Salvatore Fanali and published by Elsevier. This book was released on 2017-06-23 with total page 840 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid Chromatography: Applications, 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 knowledge of the wide variety of applications 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