Guide to Fluorine NMR for Organic Chemists PDF Download
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Author: William R. Dolbier, Jr.
Publisher: John Wiley & Sons
ISBN: 1118831098
Category : Science
Languages : en
Pages : 418
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Book Description
Following its well-received predecessor, this book offers an essential guide to chemists for understanding fluorine in spectroscopy. With over 1000 compounds and 100 spectra, the second edition adds new data – featuring fluorine effects on nitrogen NMR, chemical shifts, and coupling constants. • Explains how to successfully incorporate fluorine into target molecules and utilize fluorine substituents to structurally characterize organic compounds • Includes new data on nitrogen NMR, focusing on N-15, to portray the influence of fluorine upon nitrogen NMR chemical shifts and coupling constants • Expands on each chapter from the first edition with additional data and updated discussion from recent findings • "The flawless ordering of material covered in this stand-alone volume is such that information can be found very easily." – Angewandte Chemie review of the first edition, 2010
Author: William R. Dolbier, Jr.
Publisher: John Wiley & Sons
ISBN: 1118831098
Category : Science
Languages : en
Pages : 418
Get Book Here
Book Description
Following its well-received predecessor, this book offers an essential guide to chemists for understanding fluorine in spectroscopy. With over 1000 compounds and 100 spectra, the second edition adds new data – featuring fluorine effects on nitrogen NMR, chemical shifts, and coupling constants. • Explains how to successfully incorporate fluorine into target molecules and utilize fluorine substituents to structurally characterize organic compounds • Includes new data on nitrogen NMR, focusing on N-15, to portray the influence of fluorine upon nitrogen NMR chemical shifts and coupling constants • Expands on each chapter from the first edition with additional data and updated discussion from recent findings • "The flawless ordering of material covered in this stand-alone volume is such that information can be found very easily." – Angewandte Chemie review of the first edition, 2010
Author: Jonathan Zweigle
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Per- and polyfluoroalkyl substances (PFAS) are a large group of anthropogenic organic chemicals that are characterized by their carbon fluorine bonds. Due to their unique characteristics that include high stability, oil- and water-repellent properties and more, they are used in countless consumer products and industrial processes. While in perfluorinated compounds every C-H bond is substituted by a C-F bond, polyfluorinated compounds are only partially fluorinated and consist also of a hydrocarbon part. The fully fluorinated moieties of PFAS, usually perfluoroalkyl or perfluoroether chains, are extremely persistent in the environment. As a result of this persistence combined with the extensive use, PFAS can be detected everywhere in the environment as well as in humans. While some polyfluorinated compounds are partially transformed in the environment, they eventually form persistent end products such as perfluoroalkyl acids (PFAAs) which is why they are also referred to as precursors. The sheer number of individual PFAS makes their analytical detection very challenging. Since PFAS are industrial chemicals, the availability of reference standards is limited. Therefore, chromatographic techniques coupled to high-resolution mass spectrometry (HRMS) are necessary for a more comprehensive characterization of the PFAS in the environment. In the first part of this dissertation, methods for a prioritization and subsequent identification of PFAS in both environmental and consumer product samples were developed and validated in selected case studies. Since during so-called non-target screening (NTS), large datasets are acquired, an efficient prioritization is crucial to isolate the analytes of interest from background signals and other detected compounds. In case of PFAS, their intrinsic properties were used to separate them from other organic compounds in the HRMS datasets. The novel MD/C-m/C approach that uses the chemical mass defect (MD) and the mass (m) normalized to the carbon number (C) was theoretically evaluated with ~490,000 chemical formulas from online database to show that a wide range of PFAS can efficiently be separated from non-PFAS in the presence of other substances. PFAS with at least 55 mass percent of fluorine, a F/C ratio > 0.8, or a H/F ratio 0.8 were separable from other compound classes showing the great potential to remove unwanted compounds from HRMS datasets. To also prioritize PFAS fragmentation spectra, important fragment mass difference (or neutral losses) of common PFAS were determined, evaluated, and used to detect MS/MS spectra and identify PFAS in both extracts of coated papers and soils. This approach, combined with other NTS techniques was used to identify and semi-quantify several novel PFAS in a highly contaminated agricultural soil from north-western Germany where over 70 PFAS were detected that were previously unknown on this site. The total concentration was estimated to be 30 mg/kg total identified PFAS. Furthermore, the contamination was almost entirely dominated by perfluorinated compounds including SF5-perfluoroalkyl sulfonic acids which indicated a unique source of contamination. Eventually, several existing and here developed NTS techniques were combined into PF∆Screen, an open-source Python-based NTS tool for a vendor-independent prioritization and partial annotation of PFAS in HRMS raw data. The functionality of PF∆Screen was demonstrated by its application to four contaminated soils from south-western Germany where over 80 PFAS were identified including novel transformation products. In the second part, a photocatalytic oxidation method (PhotoTOP) was developed that allows the quantitative conversion of unknown precursors to their terminal end products perfluoroalkyl carboxylic acids (PFCAs). The PhotoTOP uses the production of hydroxyl radicals from irradiation of TiO2 (UV/TiO2) for the conversion of precursors in different samples and is complementary to the total oxidizable precursor (TOP) assay. Known precursors could be quantitatively oxidized to PFCAs and the PhotoTOP was shown to be able to almost completely conserve the perfluoroalkyl chain lengths of the oxidized precursors. This allows the prediction of chain-lengths of unknown precursors and was demonstrated by oxidation of pre-characterized PFAS-coated paper samples. A second promising advantage of the PhotoTOP is the absence of salts which simplified subsequent sample preparation and makes further direct injection with electrospray ionization MS possible. To this end, the PhotoTOP was compared with the performance of complementary methods such as the direct TOP assay, hydrolysis (total hydrolysable precursors) and fluorine sum parameters (extractable organic fluorine and total fluorine; measured by the Federal Institute for Materials Research and Testing (BAM)) to characterize non-extractable side-chain fluorinated polymers (SFPs) in functional textiles. It was shown that several textiles contained high concentrations of short and long-chain perfluoroalkyl side chains that are not extractable and therefore not amenable to mass spectrometry without prior chemical conversion.
Author: Nicholas P. Cheremisinoff
Publisher: John Wiley & Sons
ISBN: 1119363837
Category : Science
Languages : en
Pages : 271
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Book Description
This new volume provides a timely study on the environmental challenges from a specific class of perfluorinated chemical compounds (PFCs) that are now being recognized as a worldwide health threat. Recent studies report that levels of classes of PFCs known as polyfluoroalkyl and perfluoroalkyl (PFASs) exceed federally recommended safety levels in public drinking-water supplies for 6 million people in the United States and that as many as 100 million people could be at risk from exposure to these chemicals. These chemicals occur globally in wildlife and humans. Both PFCAs and PFSAs have been produced for more than 50 years, but have only become of interest to regulators and environmentalists since the late 1990s. Recent advances in analytical methodology has enabled widespread detection in the environment and humans at trace levels. These toxic chemicals have been found in outdoor and indoor air, surface and drinking water, house dust, animal tissue, human blood serum, and human breast milk. Of great concern to communities is the presence of these compounds in a number of drinking water supplies in the U.S. and other countries. This new volume provides a timely explanation of the chemicals, provides a detailed review of the regulations both in the US and European Community, explains the health risk literature, and then explores in great detail available treatment technologies. The volume is a must for public water supply facilities, industrial operations that have historically used these chemicals and face legacy pollution issues, policy makers and the general public.
Author: Imma Ferrer
Publisher: John Wiley & Sons
ISBN: 047042995X
Category : Science
Languages : en
Pages : 281
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Book Description
Time of flight mass spectrometry identifies the elements of a compound by subjecting a sample of ions to a strong electrical field. Illuminating emerging analytical techniques in high-resolution mass spectrometry, Liquid Chromatography Time-of-Flight Mass Spectrometry shows readers how to analyze unknown and emerging contaminants—such as antibiotics, steroids, analgesics—using advanced mass spectrometry techniques. The text combines theoretical discussion with concrete examples, making it suitable for analytical chemists, environmental chemists, organic chemists, medicinal chemists, university research chemists, and graduate and post-doctorate students.
Author: Jamie C. DeWitt
Publisher: Humana Press
ISBN: 3319155180
Category : Medical
Languages : en
Pages : 500
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Book Description
This book serves as a timely and comprehensive overview of the latest science for perfluoroalkyl and polyfluoroalkyl substances (PFASs), covering the development of methods for assessing PFASs in biological fluids and tissues as well as the current knowledge regarding their toxicity to vertebrate organisms. This book includes chapters on human and wildlife exposure/body burdens, reviews of metabolism and toxicological effects by organ system/developmental stage and aspects of PFAS toxicity that are driving PFAS research and regulatory oversight. Toxicological Effects of Perfluoroalkyl and Polyfluoroalkyl Substances provide critical assessments of the most controversial topics surrounding toxicological evaluation of PFASs to give readers an expert perspective on the issues. Emphasis is placed on the integration of modes and mechanisms of action with functional endpoints that are relevant to human and wildlife health. This book will be a useful resource for toxicologists, environmental chemists, risk assessors and researchers with an interest in the class of compounds known as perfluoroalkyl and polyfluoroalkyl substances.
Author: Erik Kissa
Publisher: CRC Press
ISBN: 9780824704728
Category : Science
Languages : en
Pages : 650
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Book Description
A discussion of the synthesis, problems, theories and applications of fluorinated surfactants, this second edition is updated with four new chapters on repellency and protection against soiling and staining and over 2900 references, equations, and drawings (800 more than the previous edition). It lists alphabetically and explores numerous applications of fluorinated surfactants. Called "...a most useful introduction to these fascinating materials" by the Journal of Dispersion Science and Technology and "...a coherent and stimulating handbook...the most useful book in the fluorinated surfactants field to date. Recommended." by the Journal of the Chemical Society, Faraday Transactions - this book is a source of factual data, methods of manufacture, and chemical structures for the surfactant scientist and user.
Author: Thomas P. Knepper
Publisher: Springer Science & Business Media
ISBN: 3642218717
Category : Science
Languages : en
Pages : 183
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Book Description
Due to their unparalleled effectiveness and efficiency, polyfluorinated chemicals (PFC) have become essential in numerous technical applications. However, many PFCs brought to market show limited biodegradability, and their environmental persistence combined with toxic and bioaccumulative potential have become a matter of concern in some instances. This volume highlights the synthesis of PFCs, focusing on substances with improved application and environmental properties, which are a challenge for synthetic chemists. Further, modern mass spectrometric techniques for the detection and identification of biotransformation products of PFCs are described. The sorption and leaching behavior of PFC in soil is also addressed in order to predict their fate in the environment. Several contributions discuss the monitoring of PFCs in European surface, ground and drinking waters, treatment options for PFC removal from drinking water, occurrence in food, and the human biomonitoring of PFCs.
Author:
Publisher:
ISBN:
Category : Hazardous wastes
Languages : en
Pages : 96
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Book Description
Author: Albert Lebedev
Publisher: ILM Publications
ISBN: 1906799121
Category : Science
Languages : en
Pages : 544
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Book Description
"In full colour throughout, this book describes the power of mass spectrometry in resolving environmental issues, demonstrating how real-world complex problems can be solved in a simple and elegant way."--Worldcat.
Author: Anna Kärrman
Publisher: Nordic Council of Ministers
ISBN: 9289360623
Category : Technology & Engineering
Languages : en
Pages : 156
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Book Description
This report describes a screening study of in all ninety-nine conventional and emerging per- and polyfluoroalkyl substances (PFASs) in the Nordic environment. In addition, extractable organic fluorine (EOF) was analysed. The latter can provide the amount, but not identity, of organofluorine in the samples, which in turn can be used to assess the mass balance between known and unknown PFASs. The study was initiated by the Nordic Screening Group and funded by these and the Nordic Council of Ministers through the Chemicals Group.A total of 102 samples were analyzed in this study, including bird eggs, fish, marine mammals, terrestrial mammals, surface water, WWTP effluents and sludge, and air. Samples were collected by institutes from the participating countries and self-governing areas; Denmark, Faroe Islands, Finland, Greenland, Iceland, Norway, and Sweden.
