Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 233
Book Description
The Use of Comprehensive Gas Chromatography and Time of Flight Mass Spectrometry in the Analysis of Organic Aerosol Composition
Author: Enabling the Identification, Quantification, and Characterization of Organics in Complex Mixtures to Understand Atmospheric Aerosols
Author: Gabriel Avram IsaacmanPublisher:
ISBN:
Category :
Languages : en
Pages : 167
Book Description
Particles in the atmosphere are known to have negative health effects and important but highly uncertain impacts on global and regional climate. A majority of this particulate matter is formed through atmospheric oxidation of naturally and anthropogenically emitted gases to yield highly oxygenated secondary organic aerosol (SOA), an amalgamation of thousands of individual chemical compounds. However, comprehensive analysis of SOA composition has been stymied by its complexity and lack of available measurement techniques. In this work, novel instrumentation, analysis methods, and conceptual frameworks are introduced for chemically characterizing atmospherically relevant mixtures and ambient aerosols, providing a fundamentally new level of detailed knowledge on their structures, chemical properties, and identification of their components. This chemical information is used to gain insights into the formation, transformation and oxidation of organic aerosols. Biogenic and anthropogenic mixtures are observed in this work to yield incredible complexity upon oxidation, producing over 100 separable compounds from a single precursor. As a first step toward unraveling this complexity, a method was developed for measuring the polarity and volatility of individual compounds in a complex mixture using two-dimensional gas chromatography, which is demonstrated in Chapter 2 for describing the oxidation of SOA formed from a biogenic compound (longifolene: C15H24). Several major products and tens of substantial minor products were produced, but none could be identified by traditional methods or have ever been isolated and studied in the laboratory. A major realization of this work was that soft ionization mass spectrometry could be used to identify the molecular mass and formula of these unidentified compounds, a major step toward a comprehensive description of complex mixtures. This was achieved by coupling gas chromatography to high resolution time-of-flight mass spectrometry with vacuum ultraviolet (VUV) photo-ionization. Chapters 3 and 4 describe this new analytical technique and its initial application to determine the structures of unknown compounds and formerly unresolvable mixtures, including a complete description of the chemical composition of two common petroleum products related to anthropogenic emissions: diesel fuel and motor oil. The distribution of hydrocarbon isomers in these mixtures - found to be mostly of branched, cyclic, and saturated - is described with unprecedented detail. Instead of measuring average bulk aerosol properties, the methods developed and applied in this work directly measure the polarity, volatility, and structure of individual components to allow a mechanistic understanding of oxidation processes. Novel characterizations of these complex mixtures are used to elucidate the role of structure and functionality in particle-phase oxidation, including in Chapter 4 the first measurements of relative reaction rates in a complex hydrocarbon particle. Molecular structure is observed to influence particle-phase oxidation in unexpected and important ways, with cyclization decreasing reaction rates by ~30% and branching increasing reaction rates by ~20-50%. The observed structural dependence is proposed to result in compositional changes in anthropogenic organic aerosol downwind of urban areas, which has been confirmed in subsequent work by applying the techniques described here. Measurement of organic aerosol components is extended to ambient environments through the development of instrumentation with the unprecedented capability to measure hourly concentrations and gas/particle partitioning of individual highly oxygenated organic compounds in the atmosphere. Chapters 5 and 6 describe development of new procedures and hardware for the calibration and analysis of oxygenates using the Semi-Volatile Thermal desorption Aerosol Gas chromatograph (SV-TAG), a custom instrument for in situ quantification of gas- and particle-phase organic compounds in the atmosphere. High time resolution measurement of oxygenated compounds is achieved through a reproducible and quantitative methodology for in situ "derivatization"--Replacing highly polar functional groups that cannot be analyzed by traditional gas chromatography with less polar groups. Implementation of a two-channel sampling system for the simultaneous collection of particle-phase and total gas-plus-particle phase samples allows for the first direct measurements of gas/particle partitioning in the atmosphere, significantly advancing the study of atmospheric composition and variability, as well as the processes governing condensation and re-volatilization. This work presents the first in situ measurements of a large suite of highly oxygenated biogenic oxidation products in both the gas- and particle-phase. Isoprene, the most ubiquitous biogenic emission, oxidizes to form 2-methyltetrols and C5 alkene triols, while [alpha]-pinene, the most common monoterpene, forms pinic, pinonic, hydroxyglutaric, and other acids. These compounds are reported in Chapter 7 with unprecedented time resolution and are shown for the first time to have a large gas-phase component, contrary to typical assumptions. Hourly comparisons of these products with anthropogenic aerosol components elucidate the interaction of human and natural emissions at two rural sites: the southeastern, U.S. and Amazonia, Brazil. Anthropogenic influence on SOA formation is proposed to occur through the increase in liquid water caused by anthropogenic sulfate. Furthermore, these unparalleled observations of gas/particle partitioning of biogenic oxidation products demonstrate that partitioning of oxygenates is unexpectedly independent of volatility: many volatile, highly oxygenated compounds have a large particle-phase component that is poorly described by traditional models. These novel conclusions are reached in part by applying the new frameworks developed in previous chapters to understand the properties of unidentified compounds, demonstrating the importance of detailed characterization of atmospheric organic mixtures. Comprehensive analysis of anthropogenic and biogenic emissions and oxidation product mixtures is coupled in this work with high time-resolution measurement of individual organic components to yield significant insights into the transformations of organic aerosols. Oxidation chemistry is observed in both laboratory and field settings to depend on molecular properties, volatility, and atmospheric composition. However, this work demonstrates that these complex processes can be understood through the quantification of individual known and unidentified compounds, combined with their classification into descriptive frameworks.
Comprehensive Environmental Mass Spectrometry
Author: Albert LebedevPublisher: ILM Publications
ISBN: 1906799121
Category : Science
Languages : en
Pages : 544
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.
Gas Chromatography and Mass Spectrometry: A Practical Guide
Author: O. David SparkmanPublisher: Academic Press
ISBN: 0080920152
Category : Science
Languages : en
Pages : 633
Book Description
The second edition of Gas Chromatography and Mass Spectrometry: A Practical Guide follows the highly successful first edition by F.G. Kitson, B.S. Larsen, and C.N. McEwen (1996), which was designed as an indispensible resource for GC/MS practitioners regardless of whether they are a novice or well experienced. The Fundamentals section has been extensively reworked from the original edition to give more depth of an understanding of the techniques and science involved with GC/MS. Even with this expansion, the original brevity and simple didactic style has been retained. Information on chromatographic peak deconvolution has been added along with a more in-depth understanding of the use of mass spectral databases in the identification of unknowns. Since the last edition, a number of advances in GC inlet systems and sample introduction techniques have occurred, and they are included in the new edition. Other updates include a discussion on fast GC and options for combining GC detectors with mass spectrometry. The section regarding GC Conditions, Derivatization, and Mass Spectral Interpretation of Specific Compound Types has the same number of compound types as the original edition, but the information in each section has been expanded to not only explain some of the spectra but to also explain why certain fragmentations take place. The number of Appendices has been increased from 12 to 17. The Appendix on Atomic Masses and Isotope Abundances has been expanded to provide tools to aid in determination of elemental composition from isotope peak intensity ratios. An appendix with examples on "Steps to follow in the determination of elemental compositions based on isotope peak intensities" has been added. Appendices on whether to use GC/MS or LC/MS, third-party software for use in data analysis, list of information required in reporting GC/MS data, X+1 and X+2 peak relative intensities based on the number of atoms of carbon in an ion, and list of available EI mass spectral databases have been added. Others such as the ones on derivatization, isotope peak patterns for ions with Cl and/or Br, terms used in GC and in mass spectrometry, and tips on setting up, maintaining and troubleshooting a GC/MS system have all been expanded and updated. Covers the practical instruction necessary for successful operation of GC/MS equipment Reviews the latest advances in instrumentation, ionization methods, and quantitation Includes troubleshooting techniques and a variety of additional information useful for the GC/MS practitioner A true benchtop reference A guide to a basic understanding of the components of a Gas Chromatograph-Mass Spectrometer (GC-MS) Quick References to data interpretation Ready source for information on new analyses
Advanced Techniques in Gas Chromatography-Mass Spectrometry (GC-MS-MS and GC-TOF-MS) for Environmental Chemistry
Author: Publisher: Elsevier
ISBN: 9780444626233
Category : Science
Languages : en
Pages : 0
Book Description
Gas chromatography mass spectrometry (GC-MS) has been the technique of choice of analytical scientists for many years. The latest developments in instrumentation, including tandem mass spectrometry (MS-MS) and time-of-flight (TOF) detectors, have opened up and broadened the scope of environmental analytical chemistry. This book summarizes the major advances and relevant applications of GC-MS techniques over the last 10 years, with chapters by leading authors in the field of environmental chemistry. The authors are drawn from academia, industry and government. The book is organized in three main parts. Part I covers applications of basic GC-MS to solve environmental-related problems. Part II focuses on GC-MS-MS instrumentation for the analyses of a broad range of analysis in environmental samples (pesticides, persistent organic pollutants, endocrine disruptors, etc.). Part III covers the use of more advanced GC-MS techniques using low- and high-resolution mass spectrometry for many applications related to the environment, food and industry.
Comprehensive Two-dimensional Gas Chromatography Time-of-flight Mass Spectrometry with Chemometric Analysis
Author: Amanda Elizabeth Moses SinhaPublisher:
ISBN:
Category : Gas chromatography
Languages : en
Pages : 410
Book Description
Chromatographic Analysis of the Environment
Author: Leo M.L. NolletPublisher: CRC Press
ISBN: 1315316196
Category : Technology & Engineering
Languages : en
Pages : 650
Book Description
This detailed handbook covers different chromatographic analysis techniques and chromatographic data for compounds found in air, water, and soil, and sludge. The new edition outlines developments relevant to environmental analysis, especially when using chromatographic mass spectrometric techniques. It addresses new issues, new lines of discussion, and new findings, and develops in greater detail the aspects related to chromatographic analysis in the environment. It also includes different analytical methodologies, addresses instrumental aspects, and outlines conclusions and perspectives for the future.
Application of Comprehensive Two-dimensional Gas Chromatography, Time-of-flight Mass Spectrometry and Visual Basic Script for Detailed Analysis of Fossil and Biogenic Fuels
Author: Maximilian Karl JennerweinPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Liquid Chromatography Time-of-Flight Mass Spectrometry
Author: Imma FerrerPublisher: John Wiley & Sons
ISBN: 047042995X
Category : Science
Languages : en
Pages : 281
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.
Interpretation of Mass Spectra
Author: Fred Warren McLafferty (Chemiker, USA)Publisher:
ISBN: 9780805370485
Category : Mass spectrometry
Languages : en
Pages : 278
Book Description