Download or read book A Summary of Progress Toward the Synthesis of New Chiral Stationary Phases for High Performance Liquid Chromatography written by David B. Rusterholz and published by . This book was released on 1985 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Summary of Progress Toward the Design and Synthesis of New Chiral Stationary Phases for High Performance Liquid Chromatography II Target Compounds Based on Natural Amino Acids written by David Billing Rusterholz and published by . This book was released on 1986 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Design Functionalization Synthesis and Evaluation of New Chiral Stationary Phases for U HPLC and Their Implementation in Drug Analysis enantio purification and Structural Elucidation written by Christian Geibel and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chiral liquid chromatography is a field of utmost importance for a wide range of academic and industrial applications. Drug development, environmental analysis, laboratory-based diagnostics, or structure elucidation among others, strongly rely on chiral liquid chromatography nowadays. For this reason, this cumulative thesis describes the development and applications of chiral stationary phases for enantioselective (ultra-)high performance liquid chromatography ((U)HPLC). In the first part of the thesis, new chiral stationary phases (CSPs) based on anion-exchange and zwitterionic ion exchange chiral selectors were developed. The following goals were achieved during the work on this thesis: Various silica particles were evaluated for their kinetic performance optimization for enantioselective UHPLC and a deep insight into a variety of interactions between analyte and stationary phase was gained [Publication I]. The bonding chemistry and its generation by thermic or UV-driven radical starter was evaluated and systematically optimized by introducing a solvent-free photo-click immobilization strategy resulting in low-bleeding, “platform-type” stationary phases [Publication II]. Furthermore, the functionalization of bare silica, which can be seen as the starting point of the production of a CSP-based HPLC column, was varied and optimized for fast separations by the reduction of mass transfer resistance using silatranes and thus forming thin, homogeneous monolayer of thiol functionalization in a multiple-step [Publication III] and in a single-step approach [Publication IV]. The second part of the thesis focuses on the application of enantiomer separation. This includes the elaboration of the following aspects: Since chiral methods are becoming increasingly important in the fields of metabolomics and lipidomics, a guide for the chiral analysis of branched short-chain fatty acids based on polysaccharide columns was developed [Publication V]. Furthermore, the chirality of previously unknown natural compounds was elucidated [Publication VI]. A protocol for the enantiopurification of a radiotracer was established [Publication VII]. Knowledge about chiral HPLC was used for both analytical and preparative separation in the development of potential new drugs [Publications VIII and IX]. In summary, extensive research on the design, functionalization, synthesis, and evaluation of chiral stationary phases and their scope of applications has been performed.
Download or read book An Approach to New Chiral Stationary Phases for HPLC written by Alexander William George Povey and published by . This book was released on 1991 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Environmental Applications of Chiral HPLC and Development of New Chiral Stationary Phases written by Wen-Yee Lee and published by . This book was released on 2000 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Chiral Stationary Phases for HPLC written by Abdel Fattah M. El-Walily and published by . This book was released on 1985 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Evaluation of New Chiral Phases for High Performance Liquid Chromatography written by William Garrick Etherington and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Synthesis and Characterization of Bonded Stationary Phases in High Performance Liquid Chromatography written by Steven Douglas Fazio and published by . This book was released on 1985 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of a New Polysaccharide Based Chiral Stationary Phase for High Performance Liquid Chromatography written by Jeffry J. Lynch and published by . This book was released on 1994 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis of New Chiral Gas Chromatographic Stationary Phases with Novel Selectivities written by Aroonsiri Shitangkoon and published by . This book was released on 1995 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis of Chiral Stationary Phases for HPLC written by W. C. Ferraz Lourenco and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Chiral Stationary Phases for High Performance Liquid Chromatographic Fractionation of Racemates written by Tau-Being Thomas Hsu and published by . This book was released on 1986 with total page 104 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 Optimization of Chiral Separations in High Performance Liquid Chromatography Using Polysaccharide Chiral Stationary Phases written by Yunan Miao and published by . This book was released on 1996 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Evaluation of Thermo responsive Stationary Phases for High Performance Liquid Chromatography HPLC written by Farnoosh Roohi and published by . This book was released on 2009 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Surface confined Ionic Liquid Stationary Phases for High Performance Liquid Chromatography written by David S. Van Meter (III.) and published by . This book was released on 2008 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt:
