Download or read book Evaluation of PS DVB Stationary Phase in Reversed phase High Performance Liquid Chromatography written by Susan Pedigo and published by . This book was released on 1987 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reversed Phase High Performance Liquid Chromatography written by Ante M. Krstulovic and published by . This book was released on 1982-05-04 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive problem-solving approach to reversed-phase high-performance liquid chromatography covering the theoretical aspects and practical information needed in diverse areas of research. Also reviews RPLC applications in the biomedical/biochemical field.
Download or read book High temperature reversed phase high performance liquid chromatography on a poly styrene divinylbenzene copolymer stationary phase written by Hong Heng See and published by . This book was released on 2003 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Temperature Reversed phase High Performance Liquid Chromatography on a Poly styrene divinylbenzene Copolymer Stationary Phase written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book How to Use Reverse phase HPLC written by Gábor Szepesi and published by Wiley-VCH. This book was released on 1992 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Application of High Performance Liquid Chromatography with Superheated Water Eluent and PS DVB Stationary Phase to the Analysis of Barbiturates written by and published by . This book was released on 2003 with total page 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 Studies of Reversed Phase High Performance Liquid Chromatography RP HPLC Stationary Phases written by Richard Charles Watson and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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
Download or read book Acid Stable Hyper Crosslinked Stationary Phases for the Reversed Phase High Performance Liquid Chromatographic Separation of Basic and Biological Analytes written by Lianjia Ma and published by . This book was released on 2005 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Synthesis and Characterization of Reversed Phase Stationary Phases for High Performance Liquid Chromatography written by Karen Wink Barnes and published by . This book was released on 1986 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reversed phase liquid chromatography (RPLC) is a widely used separation technique today. The stationary phase, composed of hydrocarbon moieties chemically bound to a silica support, is commonly prepared by refluxing the silica with a reactive silane in an appropriate solvent. Siloxane bonds, Si-O-Si, are formed. There are limitations to RPLC in that nonhomogeneous surface coverages, detrimental to efficient separations, result from the bonding process, and because the reaction is never complete due to steric restrictions. Also, silica is soluble at high pH values, and the Si-C bond binding the hydrocarbon to the silica is labile at low pH ranges. Thus, the usable pH range for silica stationary phases is 2.5 to 7.5, and often this range is too narrow to allow the separation of a mixture. The use of ultrasonic cavitation to catalyze silane bonding was investigated to dtermine whether the vigorous ultrasonic process would drive reagents into the surface pores and better distribute the hydrocar bonaceous reagent, thereby producing a more efficient stationary phase. Tandem reactions proved that ultrasonic bonding procedures are as effective as the refluxed, and that the chromatographic efficiency of the ultrasonic phases was comparable, if not superior, to the refluxed. Chromatographic tests also indicated the ultrasonic phases were comparable to commercially available phases. The reproducibility of the reactions and the effect of acoustic power and heat were also investigated. A second set of experiments investigated substitution of alumina for silica because the alumina crystalline structure remains intact over a pH range of 2 to 12. A trifunctional modification scheme generating a thick cross-linked hydrocarbon matte was used because the Al-0 bond is susceptible to hydrolysis, which strips the bound hydrocarbons, by polar RP solvents. Five aluminas were bonded and tested for chromatographic utility. Reaction conditions were optimized, and ultrasonic bonding was investigated. It was found that alumina with a sufficiently active surface is modifiable, and that the modified surface is remarkably stable for use with acidic and basic buffers and in neutral, polar solvent mixtures. The chromatographic utility of alumina phases was demonstrated and compared with the silica results.
Download or read book A New Stationary Phase for Reverse phase High Performance Liquid Chromatography written by Ruby W. Tam and published by . This book was released on 1995 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Evaluation of Four Novel Stationary Phases in High Pressure Liquid Chromatography written by Niloofar Salehi and published by . This book was released on 2012 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: High pressure liquid chromatography is one of the most frequently used methods for the separation of mixtures. Chemically modified silica hydride stationary phases, due to their unique selectivity and versatility, have been the focus of an increasing number of studies in the past several years. The objective of fabricating stationary phases with dual properties is to achieve separation of both polar and non-polar components in a single analysis. Due to an increasing demand in the fields of drug discovery, proteomics, and metabolomics to analyze numerous samples with a wide range of polarities, there is a need for more versatile stationary phases for a wide range of applications. In order to meet the above objective, in this research four novel silica hydride-based columns were synthesized using a hydrosilation procedure. The characterization of each column was done using a series of polar and nonpolar compounds by studying their aqueous normal phase and reversed-phase chromatographic behavior. Under these conditions, it turned out that two columns showed both RP and ANP behaviors. Of the remaining columns, one exhibited ANP behavior only and the other performed only in the reversed-phase mode.
Download or read book Novel Stationary Phases on Silica and Zirconia for the Reversed Phase High Performance Liquid Chromatographic Separation of Acidic and Basic Analytes written by Brian Charles Trammell and published by . This book was released on 2003 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reversed Phase High Performance Liquid Chromatography on a Polymer Column with Alkaline Mobile Phase as Improved Drug Screening Technique written by Samer Dashi and published by . This book was released on 2000 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Novel Stability Indicating Methods Using Liquid Chromatography written by Mukesh Maithani and published by Springer. This book was released on 2019-08-16 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reversed-phase high-performance liquid chromatography (RP-HPLC) has become the most widely used method for pharmaceutical analysis, as it ensures accuracy, specificity and reproducibility for the quantification of drugs, while avoiding interference from any of the excipients that are normally present in pharmaceutical dosage forms. This book presents a simple methodology for developing stability-indicating methods and offers a ‘how-to guide’ to creating novel stability-indicating methods using liquid chromatography. It provides the detailed information needed to devise a stability-indicating method for drug substances and drug products that comply with international regulatory guidelines. As such, it is a must-read for anyone engaged in analytical and bioanalytical chemistry: professionals at reference, test, and control laboratories; students and academics at research laboratories, and scientists working for chemical, pharmaceutical, and biotechnology companies.
Download or read book Development and Evaluation of New Reversed Phase Packing Materials for Ultra high Pressure Liquid Chromatography written by J. Scott Mellors and published by . This book was released on 2005 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:
