Download or read book Development of Micellar Selectivity Triangle for Classification of Pseudo stationary Phase Selectivity in Electrokinetic Chromatography written by Cexiong Fu and published by . This book was released on 2005 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keywords: electrokinetic chromatography, micellar selectivity triangle, reversed phase liquid chromatography, chemometric methods, chemical selectivity.
Download or read book Development of Micellar Selectivity Triangle for Classification of Pseudo stationary Phase Selectivity in Electrokinetic Chromatography written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A novel Micellar selectivity triangle (MST) was developed to rationalize and classify the chemical selectivities for a wide variety of pseudo-phases in Electrokinetic Chromatography (EKC). The descriptors of polar selectivities for constructing the MST were derived from the linear solvation energy relationships (LSER). The effects of solvent modification of micelles, mixed-micellar systems along with surfactant type on the pseudo-phase selectivities were investigated using the MST. To quantitatively describe the similarities and differences of the chemical selecitivities, a phase selectivity ranking system was constructed on the basis of the Euclidean distance between objects. Chemometric methods including the principal component analysis (PCA), hierarchical clustering and k-means clustering were used to elucidate the classification and characterization of the micellar phases in different perspectives. The results form the MST and the chemometric methods were in generally good agreement. The micellar selectivity triangle was used as a guideline for optimizing the separation of 20 Phenylthiohydantoin (PTH) amino acids. The effects of the surfactant type and concentration, temperature and organic solvent additives on the PTH amino acids separation were evaluated. Additionally, the substituent constants of these PTH amino side chain obtained from the EKC methods were compared to those obtained from octanol-water partitioning and free energy of transferring amino acid moieties from the globular proteins interior to surface. Finally, the combined use of the unified selectivity triangle (UST), PCA and cluster analysis was explored for the comparison of the chemical selectivity between the two powerful chromatographic techniques, EKC and RPLC. The database consisted of 518 reversed-phase systems and 83 pseudo-phases. The primary factors to influence the phase selectivity of the two techniques were identified and compared. Suggestions for future works are also discussed.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2007 with total page 854 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization of Chemical Selectivity in Micellar Electrokinetic Chromatography written by Mark Doane Trone and published by . This book was released on 1999 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Band Broadening and Selectivity in Micellar Electrokinetic Chromatography written by Kurt Richard Nielsen and published by . This book was released on 1994 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Pseudo stationary Phases for Separations in Electrokinetic Chromatography written by Judson Leroy Haynes and published by . This book was released on 1999 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization and Application of Pseudostationary Phases in Micellar Electrokinetic Chromatography MEKC written by Jefferson Gail Bumgarner and published by . This book was released on 1996 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation and Application of Stationary Phase Selectivity for Drug Analysis written by Raigamage Wimal H. Perera and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite the wide range of HPLC stationary phases available for reversed-phase high-performance liquid chromatography (RP-HPLC) and the in-depth studies using probes to highlight differences between them, there is very little in the way of stationary phases which offer selectivity that is substantially different from that offered by the very commonly used alkyl-silicas. Therefore, the primary aim of the research programme was to explore and try to exploit LC stationary phases which offered genuinely different selectivity to alkyl-silicas for typical drug applications. Chiral stationary phases (CSP) potentially had different selectivity and in this context a secondary aim was to explore aspects of the enantioselectivity of CSP as well as their chemical selectivity. Claims of orthogonal selectivity had been made for pentafluorophenyl (PFP) phases and phases exhibiting the hydrophilic interaction liquid chromatography (HILlC) mode. However, the Ultra PFP phase was found to be very similar in selectivity to ACE 5 C18 for both amitriptyline and acemetacin related compounds. The ZIC-HILlC phase was shown to behave as a reversed-phase material at high aqueous content in the mobile phase. There was some indication of selectivity orthogonal to that of ACE 5 C18 with low aqueous content in the mobile phase but this occurred at low retention and with mobile phases unsuitable for use with C18 phases in coupled (column or phase) systems. Nonetheless the work carried out shed more light on the mechanisms taking place in the HILlC mode which is currently attracting so much interest. Also it was possible to put ZIC-HILlC to good use for polar plant metabolites and other applications. Chiral stationary phases (CSP) also offered the prospect of selectivity orthogonal to that of C18 phases. Given the proliferation of such phases though and the fact that it would be useful to use CSP that gave chiral separations for a broad spectrum of compound classes as well as giving orthogonal separations between different compounds, it was decided to carry out comparative studies of CSP classes in order to identify any redundancies and to seek out CSP that were complementary to one another. The Regis Whelk-01 CSP was shown to be much superior to other higher-generation Pirkle-concept CSP such as DACH-DNB and ULMO. Also it was shown to be complementary to the Chiralcel OD derivatised polysaccharide CSP and that both had something to offer alongside the widely used Chiralpak AD derivatised polysaccharide CSP. It was also found that a series of Chiralcel OD clones were virtually identical to Chiralcel OD and similarly for Chiralpak AD clones. Chiralpak lA, an immobilised version of Chiralpak AD, was not markedly less enantioselective than Chiralpak AD. Chiralcel OJ was less enantioselective than Chiralpak AD but the gap in performance was not as wide as between Whelk-01 and the other Pirkle-concept CSP. The information gathered during these studies should prove to be of enormous value for further work in chiral LC method development screening. Before embarking on applications work utilising the stationary phase selectivity that had been found, a study was carried out on the effectiveness of the high efficiencies obtainable with short run times through ultra-performance liquid chromatography (UPLC). It was found that, for a range of pharmaceutical applications, that it was still necessary in each case to adjust selectivity before increasing speed through working at higher temperatures with faster flow rates. In the course of this work some exceptionally high speed separations for example for paroxetine and related substances, benzodiazepines and flurbiprofen and related substances, were developed. With respect to the evaluation of CSP as orthogonal phases to alkyl silicas under reversed-phase conditions, the Whelk-01 CSP showed promise. However on closer inspection it was found that the Whelk-01 CSP had very similar selectivity to the alkyl silica phase, ACE 5 C18, and deviation from this only occurred in instances when there was interaction with the chiral recognition site to give a separation of enantiomers. This prompted the notion that, rather than using Whelk- 01 in a coupled column system with ACE 5 C18, it could be used on its own for the separation of both trace enantiomer and all other related substances. This was shown to be possible using (S)-naproxen, laevokalim and (S)-flurbiprofen as illustrative examples. The evaluation of the enantioselectivity of CSP led to an optimised resolution (suitable for scaling up for preparative work) of the enantiomers of the former 'legal-high' drug, mephedrone, on Whelk-01 under normal phase conditions. It was also shown that the infrequently used Chiralcel OJ derivatised polysaccharide CSP was ideal for developing an assay to determine trace amounts of (R)-nicotine in (S)-nicotine. Overall, the information obtained on stationary phase selectivity and retentivity through evaluation and application will be of great value in HPLC and UHPLC column selection and also selection of orthogonal phases for coupled column systems but, ultimately, moving forward, most value may be in aiding the design of two-dimensional LC systems for complex mixture analysis. This would particularly apply to the use of CSP with reversed-phase eluents in achiral-chiral systems.
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 The Next Ancient World written by Jennifer Michael Hecht and published by . This book was released on 2001 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hecht's poetry has full measures of play, wisdom, sheer joy of invention. Her poems demonstrate a mastery of craft and a unique voice buoyed by brilliance. She explains-in her endlessly appealing half-outrageous, half-conspiratorial voice-her purpose: a guidebook for those who come after. WE are the next ancient world, and Hecht makes myths out of our daily lives.
Download or read book Liquid Phase Extraction written by Colin F. Poole and published by Elsevier. This book was released on 2019-08-29 with total page 818 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid Phase Extraction thoroughly presents both existing and new techniques in liquid phase extraction. It not only provides all information laboratory scientists need for choosing and utilizing suitable sample preparation procedures for any kind of sample, but also showcases the contemporary uses of sample preparation techniques in the most important industrial and academic project environments, including countercurrent chromatography, pressurized-liquid extraction, single-drop Microextraction, and more. Written by recognized experts in their respective fields, it serves as a one-stop reference for those who need to know which technique to choose for liquid phase extraction. Used in conjunction with a similar release, Solid Phase Extraction, it allows users to master this crucial aspect of sample preparation. Defines the current state-of-the-art in extraction techniques and the methods and procedures for implementing them in laboratory practice Includes extensive referencing that facilitates the identification of key information Aimed at both entry-level scientists and those who want to explore new techniques and methods
Download or read book Handbook of Pharmaceutical Analysis by HPLC written by Satinder Ahuja and published by Elsevier. This book was released on 2005-02-09 with total page 679 pages. Available in PDF, EPUB and Kindle. Book excerpt: High pressure liquid chromatography–frequently called high performance liquid chromatography (HPLC or, LC) is the premier analytical technique in pharmaceutical analysis and is predominantly used in the pharmaceutical industry. Written by selected experts in their respective fields, the Handbook of Pharmaceutical Analysis by HPLC Volume 6, provides a complete yet concise reference guide for utilizing the versatility of HPLC in drug development and quality control. Highlighting novel approaches in HPLC and the latest developments in hyphenated techniques, the book captures the essence of major pharmaceutical applications (assays, stability testing, impurity testing, dissolution testing, cleaning validation, high-throughput screening). A complete reference guide to HPLC Describes best practices in HPLC and offers 'tricks of the trade' in HPLC operation and method development Reviews key HPLC pharmaceutical applications and highlights currents trends in HPLC ancillary techniques, sample preparations, and data handling
Download or read book Capillary Zone Electrophoresis written by František Foret and published by . This book was released on 1993 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Planar Lipid Bilayers and Liposomes written by Ales Iglic and published by Academic Press. This book was released on 2012-09-04 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Planar Lipid Bilayers and Liposomes volumes cover a broad range of topics, including main arrangements of the reconstituted system, namely planar lipid bilayers as well as spherical liposomes. The invited authors present the latest results of their own research groups in this exciting multidisciplinary field. Incorporates contributions from newcomers and established and experienced researchers Explores the planar lipid bilayer systems and spherical liposomes from both theoretical and experimental perspectives Serves as an indispensable source of information for new scientists
Download or read book Handbook of Forensic Drug Analysis written by Fred Smith and published by Elsevier. This book was released on 2004-12-31 with total page 585 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Handbook of Forensic Drug Analysis is a comprehensive chemical and analytic reference for the forensic analysis of illicit drugs. With chapters written by leading researchers in the field, the book provides in-depth, up-to-date methods and results of forensic drug analyses. This Handbook discusses various forms of the drug as well as the origin and nature of samples. It explains how to perform various tests, the use of best practices, and the analysis of results. Numerous forensic and chemical analytic techniques are covered including immunoassay, gas chromatography, and mass spectrometry. Topics range from the use of immunoassay technologies for drugs-of-abuse testing, to methods of forensic analysis for cannabis, hallucinogens, cocaine, opioids, and amphetamine. The book also looks at synthetic methods and law enforcement concerns regarding the manufacture of illicit drugs, with an emphasis on clandestine methamphetamine production. This Handbook should serve as a widely used reference for forensic scientists, toxicologists, pharmacologists, drug companies, and professionals working in toxicology testing labs, libraries, and poison control centers. It may also be used by chemists, physicians and those in legal and regulatory professions, and students of graduate courses in forensic science. - Contributed to by leading scientists from around the world - The only analysis book dedicated to illicit drugs of abuse - Comprehensive coverage of sampling methods and various forms of analysis
Download or read book High Performance Thin Layer Chromatography HPTLC written by ManMohan Srivastava and published by Springer Science & Business Media. This book was released on 2010-11-15 with total page 401 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present edited book is the presentation of 18 in-depth national and international contributions from eminent professors, scientists and instrumental chemists from educational institutes, research organizations and industries providing their views on their experience, handling, observation and research outputs on HPTLC, a multi-dimensional instrumentation. The book describes the recent advancements made on TLC which have revolutionized and transformed it into a modern instrumental technique HPTLC. The book addresses different chapters on HPTLC fundamentals: principle, theory, understanding; instrumentation: implementation, optimization, validation, automation and qualitative and quantitative analysis; applications: phytochemical analysis, biomedical analysis, herbal drug quantification, analytical analysis, finger print analysis and potential for hyphenation: HPTLC future to combinatorial approach, HPTLC-MS, HPTLC-FTIR and HPTLC-Scanning Diode Laser. The chapters in the book have been designed in such away that the reader follows each step of the HPTLC in logical order.
Download or read book HPLC Columns written by Uwe D. Neue and published by Wiley-VCH. This book was released on 1997-07-28 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: An in-depth guide to HPLC column technology High-performance liquid chromatography and its derivative techniques have become the dominant analytical separation tools in the pharmaceutical, chemical, and food industries; environmental laboratories; and therapeutic drug monitoring. Although the column is the heart of the HPLC instrument and essential to its success, until now, no book has focused on the theory and practice of column technology. HPLC Columns provides thorough, state-of-the-art coverage of HPLC column technology for the practicing technician and academician alike. Along with a comprehensive discussion of the chemical and physical processes of the HPLC column, it includes fundamental principles, separation mechanisms and available technologies, column selection criteria, and special techniques. Special features include: * Comprehensive overview of state-of-the-art HPLC column technology * Explanation of the underlying principles of HPLC columns * Methods for selecting columns * Practical advice on using and applying columns, including examples * Section by M. Zoubair El Fallah on methods development * Special techniques, including preparative chromatography, continuous chromatography, and the simulated moving bed * Troubleshooting section HPLC Columns helps laboratory practitioners make better choices in column selection, methods development, and troubleshooting: it is also an excellent textbook for graduate-level courses and HPLC short courses.
