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Download or read book Gas Chromatographic Enantiomer Separation of Atropisomeric PCBs Using Modified Cyclodextrins as Chiral Phases written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Wilfried A. König
Publisher :
ISBN 13 :
Total Pages : 184 pages
Book Rating : 4.0/5 ( download)
Download or read book Gas Chromatographic Enantiomer Separation with Modified Cyclodextrins written by Wilfried A. König and published by . This book was released on 1992 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Weihua Tang
Publisher : Springer Science & Business Media
ISBN 13 : 3642376487
Total Pages : 266 pages
Book Rating : 4.6/5 (423 download)
Download or read book Modified Cyclodextrins for Chiral Separation written by Weihua Tang and published by Springer Science & Business Media. This book was released on 2013-05-24 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modified Cyclodextrins for Chiral Separation offers a review of the latest advances in developing modified cyclodextrins as chiral selectors for various chromatographic and electromigration techniques. Over the years, many descriptions of chiral separation have appeared in academic journals and books, but most of them have been devoted to either the development of analytical methods and protocols or the summary of different chiral selectors, including cyclodextrins for chiral separation applications. This is in marked contrast to this volume which focuses on the research endeavors concerning the development of cyclodextrin derivatives specifically as either chiral mobile phases for capillary electrophoresis, or chiral stationary phases for various chromatographic techniques including gas chromatography, or high-performance liquid chromatography and supercritical fluid chromatography. The ongoing thread in this book is the synthesis of structurally-defined cyclodextrin derivatives and their applications in enantiomer separation by means of different analytical techniques. Modified Cyclodextrins for Chiral Separation is intended for those who are interested in expanding their knowledge of cyclodextrin chemistry and chiral separation, and in what cyclodextrin modification can be made to suit the needs of chiral selectors for different analytical techniques. It primarily focuses on the state-of-the-art cyclodextrin chemistry which is the basis for all chiral selectors used in these chiral separation techniques. Weihua Tang, PhD, is a professor at the Key Laboratory of Soft Chemistry and Functional Materials, Ministry of Education, Nanjing University of Science and Technology, China. Siu-Choon Ng, PhD, is a professor at the Division of Chemical and Biomedical Engineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore. Dongping Sun, PhD, is a professor at the Key Laboratory of Soft Chemistry and Functional Materials, Ministry of Education, Nanjing University of Science and Technology, China.
Author : Eisuke Takahisa
Publisher :
ISBN 13 :
Total Pages : 230 pages
Book Rating : 4.:/5 (163 download)
Download or read book Modified Cyclodextrins as Chiral Stationary Phases for Capillary Gas Chromatographic Separation of Enantiomers written by Eisuke Takahisa and published by . This book was released on 2005 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modified Cyclodextrins as Chiral Stationary Phases for Capillary Gas Chromatographic Separation of Enantiomers written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Cyclodextrin (CD) derivatives are widely used as chiral stationary phases in capillary gas chromatography. Their performance depends substantially on the side chains attached to the hydroxyl groups of the glucose moieties. In this study new classes of CD-derivatives suitable for gas chromatographic (GC) separation of enantiomers were synthesized by introducing (i) acetal functions and (ii) chiral acyl moieties at positions 2 and 3 of the glucose units. Octakis(2,3-di-O-methoxymethyl-6-O-tert-butyldimethylsilyl)-g-cyclodextrin (2,3- MOM-6-TBDMS-g-CD) obtained by reaction of 6-O-TBDMS-g-cyclodextrin with methoxymethylchloride (MOM-Cl) was synthesized as first representative of cyclodextrin GC stationary phases containing alkoxymethyl side chains. The structure was confirmed by NMR and mass spectrometry. The suitability of the material diluted in polysiloxane as GC stationary phase was shown. Enantioseparations could be achieved for a broad spectrum of chiral volatiles from various chemical classes. Structural influences of the analytes on the enantiodifferentiations were demonstrated. High separation factors were observed for the hydroxyketone acetoin (a = 1.8) and some methyl branched ketones. Pronounced enantioseparations were also determined for cyclic pentenolone and furanone derivatives. To investigate the impact of the size of the CD torus, the 2,3-MOM-derivatives of the b- and a-CD analogs were synthesized. The spectrum of compounds for which enantiomers could be separated on 2,3-MOM-6-TBDMS-b-CD was more limited and the enantioseparations achieved were generally less pronounced compared to the g-CD derivative. However, for 2-alkyl esters unusually high separation factors (a up to 4.31) were observed. Using 2-pentyl acetate as example, phenomena underlying the enantioseparation were investigated by determining thermodynamic parameters. The data showed that only one enantiomer is retained significantly on the chiral stationary phase whereas the other one behaves.
Author : Roland Kallenborn
Publisher : Springer Nature
ISBN 13 : 3030624560
Total Pages : 331 pages
Book Rating : 4.0/5 (36 download)
Download or read book Chiral Environmental Pollutants written by Roland Kallenborn and published by Springer Nature. This book was released on 2021-01-29 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph contains a survey on the role of chirality in ecotoxicological processes. The focus is on environmental trace analysis. Areas such as toxicology, ecotoxicology, synthetic chemistry, biology, and physics are also covered in detail in order to explain the different properties of enantiomers in environmental samples. This monograph delivers a comprehensive survey for environmental trace analysts, analytical chemists, ecotoxicologists, food scientists and experienced lab workers.
Author : Sheree N. Allen
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (787 download)
Download or read book The Preparation of Novel Modified Cyclodextrins and Their Application in Enantioseparations by Gas Chromatography written by Sheree N. Allen and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Since biological processes depend on the stereospecific creation and conversion of chiral molecules, each enantiomer of a molecule can have a different biological effect. While numerous synthetic drugs are sold in racemic form for reasons of cost and convenience, in many cases one of the two enantiomers of a drug will cause undesirable and perhaps even devastating effects. Therefore, effective methods for the separation and quantification of enantiomers are of great importance. Enantiomers can be separated only with the use of systems containing an optically active chiral selector. Modified cyclodextrins (CDs) are widely used as chiral selectors by virtue of their ability to form inclusion complexes. Because of the remarkably high efficiency, and sensitivity of chiral gas chromatography (GC), chiral separations by this method represent a preferred method for enantiomer analysis. The basic property of CDs that allows them to be successful for enantiomer separations is their ability to form selective inclusion complexes with a wide variety of organic molecules. The preparation and application of modified cyclodextrins for the GC separation of enantiomers is a focal point of this research. In effort to identify useful new derivatives, modifications involving unique and separate reaction of the secondary hydroxyl groups and/or annulations bridging the secondary oxygens have been examined. Several new cyclodextrin derivatives, e.g. per(6-OTBS-2,3-O-diformyl)-[beta]-CD, per(6-OTBS-2,3-O-cyclodimethylsilyl)-[beta]-CD, per(6-deoxy-2,3-O-cyclodimethylsilyl)-[beta]-CD and a mixed formyl/acetyl phase have been synthesized and evaluated as components of stationary phases for capillary GC. The efficiency of each new phase to separate enantiomers was evaluated against a 30 analyte panel to evaluate the influence of the different substituents on the selectivity. These enantioseparations were also compared to those observed on four commercially available chiral phases using the same 30 analyte panel. Overall, this work resulted in nine new CD derivatives and the discovery of a new chiral selector that is comparable in efficiency to what is currently commercially available.
Author : Wolfgang König
Publisher : Wiley-VCH
ISBN 13 : 9783527297122
Total Pages : 152 pages
Book Rating : 4.2/5 (971 download)
Download or read book Gas Chromatographic Enantiomer Separation with Modified Cyclodextrins written by Wolfgang König and published by Wiley-VCH. This book was released on 1999-01-06 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Larry G. Hansen
Publisher : University of Illinois Press
ISBN 13 : 0252047087
Total Pages : 432 pages
Book Rating : 4.2/5 (52 download)
Download or read book PCBs written by Larry G. Hansen and published by University of Illinois Press. This book was released on 2023-12-11 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Though polychlorinated biphenyls (PCBs) have been banned in the United States for more than thirty years, the toxic effects of their presence in local environments continue to be a significant public health concern. PCBs: Human and Environmental Disposition and Toxicology brings together more than fifty established specialists on PCB toxicity to discuss recent trends and specialized investigations of PCB influences on the environment and on humans. Renowned scientists including Paul S. Cooke, Takeshi Nakano, Tomas Trnovec, Deborah C. Rice, Linda S. Birnbaum, and Charles S. Wong present cutting-edge research on Hudson River PCBs, human contamination, homologue profiles, high PCB exposure in Slovakia, and PCB effects on the thyroid hormone, nutrition, and estrogen levels in humans and animals. Focusing on the detection, movement, metabolism, toxicity, remediation, and risk assessment of PCB contamination, this multi-disciplinary study is a valuable resource for regulatory agencies and scientists working with PCBs.
Author : Tibor Cserháti
Publisher : Royal Society of Chemistry
ISBN 13 : 1847550673
Total Pages : 168 pages
Book Rating : 4.8/5 (475 download)
Download or read book Cyclodextrins in Chromatography written by Tibor Cserháti and published by Royal Society of Chemistry. This book was released on 2007-10-31 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cyclodextrins can form complexes with a wide variety of organic and inorganic compounds, a property which can prove useful when trying to separate complex mixtures. This book provides an up-to-date and critical evaluation of the application of cyclodextrins in many fields of chromatography (including thin layer, gas-liquid, high performance liquid and supercritical fluid chromatography; capillary electrophoresis; and isotacophoresis). Whilst mainly practical in nature, the book also looks briefly at the theoretical background for the various techniques. Any professional working with chromatography will welcome this unique book as both a practical compilation of methods and a source of reference to the literature regarding the use and impact of cyclodextrins in chromatography.
Author : R. Kallenborn
Publisher : Springer Science & Business Media
ISBN 13 : 3662062437
Total Pages : 222 pages
Book Rating : 4.6/5 (62 download)
Download or read book Chiral Environmental Pollutants written by R. Kallenborn and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph contains a survey on the role of chirality in ecotoxicological processes. The focus is on environmental trace analysis. Areas such as toxicology, ecotoxicology, synthetic chemistry, biology, and physics are also covered in detail in order to explain the different properties of enantiomers in environmental samples. This monograph delivers a comprehensive survey for environmental trace analysts, analytical chemists, ecotoxicologists, food scientists and experienced lab workers.
Author : Kenneth W. Busch
Publisher : Elsevier
ISBN 13 : 0080469280
Total Pages : 721 pages
Book Rating : 4.0/5 (84 download)
Download or read book Chiral Analysis written by Kenneth W. Busch and published by Elsevier. This book was released on 2011-10-13 with total page 721 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chiral Analysis covers an important area of analytical chemistry of relevance to a wide variety of scientific professionals. The target audience is scientific professionals with an undergraduate background in chemistry or a related discipline, specifically organic chemists, researchers in drug discovery, pharmaceutical researchers involved with process analysis or combinatorial libraries, and graduate students in chemistry. Chapters have been written with the nonspecialist in mind so as to be self-contained. * Broad coverage - spectroscopic and separation methods covered in a single volume * Up-to-date and detailed review of the various techniques available and/or under development in this field * Contributions from leading experts in the field
Author : Adel Khalil Mish'al
Publisher :
ISBN 13 :
Total Pages : 366 pages
Book Rating : 4.:/5 (895 download)
Download or read book Gas Chromatographic Enantiomer Separation with Modified _-cyclodextrins written by Adel Khalil Mish'al and published by . This book was released on 1997 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Adel Khalil Abdulla Mish'al
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (127 download)
Download or read book Gas Chromatographic Enantiomer Separation with Modified B-cyclodextrin written by Adel Khalil Abdulla Mish'al and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :
Publisher :
ISBN 13 :
Total Pages : 604 pages
Book Rating : 4.6/5 (156 download)
Download or read book Journal of Chromatography written by and published by . This book was released on 2002 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt:
![Download Design and Synthesis of Novel [beta]-cyclodextrins and Their Application as Chiral Stationary Phases for Gas Chromatography PDF Online Free](https://books.google.com/books/content/images/frontcover/DX6zAQAACAAJ?fife=w200-h370)
Author : Tiffany R. Turner Hayden
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (787 download)
Download or read book Design and Synthesis of Novel [beta]-cyclodextrins and Their Application as Chiral Stationary Phases for Gas Chromatography written by Tiffany R. Turner Hayden and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Enantiomers can be directly separated only with use of systems containing a chiral selector. Cyclodextrins (CDs) and modified cyclodextrins have been used as chiral selectors for their ability to form host-guest complexes with various analytes. The scaffold of the CD allows for assembly of functional groups with controlled geometry. CDs can be readily modified through substitution of the hydroxyl groups, giving rise to derivatives with significantly different properties, especially increased solubility and controlling the hydrophobicity of the cavity. Even though CDs can be readily modified, the syntheses can be tedious and complicated with various protecting group strategies to control the reactivity of the various alcohols. The preparation of modified cyclodextrins for use as chiral stationary phases (CSP) for gas chromatography (GC) is the focal point of this research. Our effort to identify useful new [beta]-CD derivatives involved attempts to make bridged (annulated) derivatives, could increase the thermal stability of the derivatives, and change the length, width and polarity of the CD cavity. To date, there are no reports of annulated CD derivatives in the chemical literature. In the process of evaluating a wide range of electrophiles that could accomplish annulation, several new [beta]-CD derivatives, i.e., per(6-O-TBS-2,3-O-cyclodimethylsilyl)- [beta]-CD, per(6-O-TBS-2,3-O-cyclodiphenylsilyl)- [beta]-CD, per(6-O-Pivaloyl-2,3-O-cyclodimethylsilyl)-[beta]-CD, per(6-deoxy-2,3-O-methyl)- [beta]-CD, and per(6-deoxy-2,3-O-allyl)- [beta]-CD, were synthesized. Two of the new derivatives were evaluated as components of stationary phases for GC, per(6-O-TBS-2,3-Ocyclodimethylsilyl)-[beta]-CD and per(6-deoxy-2,3-O-methyl)-[beta]-CD. Overall, this work resulted in five new CD derivatives.
Author : Wilfried A. König
Publisher :
ISBN 13 :
Total Pages : 128 pages
Book Rating : 4.3/5 (91 download)
Download or read book The Practice of Enantiomer Separation by Capillary Gas Chromatography written by Wilfried A. König and published by . This book was released on 1987 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
