Download or read book Characterisation and Field Deployment of a Novel Quantitative Time of flight Aerosol Mass Spectrometer ToF AMS written by Silke S. Hings and published by . This book was released on 2007 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development Characterization and First Field Deployments of a Novel Aerosol Mass Spectrometer Combining Laser Ablation and Flash Vaporization Techniques for Aircraft Application at High Altitudes written by Andreas Hünig and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Particulate Pollution by Aerosol Mass Spectrometry written by Courtney Leigh Herring and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric aerosols impact human health, climate, and air pollution and arrive in the atmosphere by countless number of sources. One of the largest uncertainties in understanding these impacts is due to limitations in our understanding of the organic aerosol (OA) components. To understand this complex mixture of thousands of compounds accurate high-resolution chemical speciation is needed. An Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS or HR-AMS) was deployed in two separate month-long studies to measure atmospheric particulate pollution. The first study, at the Lovelace Respiratory Research Institute (LRRI), focused on the measurement of gasoline and diesel engine exhaust under various loads and dilutions in controlled chamber experiments. HR-AMS data demonstrated clean signal associated with 53 polycyclic aromatic hydrocarbon (PAH) compounds. PAHs are of interest due to their carcinogenic implication and negative health effects especially when associated with submicron particles. From this work a novel methodology was developed for quantifying these compounds by their molecular ion signal (P-MIP). In the second study, conducted in Yakima, WA, ambient wintertime pollution was characterized and the OA components were deconvolved using positive matrix factorization (PMF). This investigation resulted in the identification of two new amine associated factors which were identified by mass spectra peaks from six dominant amine ions (C3H8N+, C2H6N2+, C4H 10N+, C3H8N2 +, C5H12N+, and C6H 14N+). Amine ions are of interest to atmospheric research because of their implications on climate and formation of new particles. The unifying implication from both studies was the utilization of the HR-AMS to identify atmospheric pollutants that continue to generate ongoing research interests (due to their impacts on climate, pollution, or human health) and are typically difficult to measure by the HR-AMS. Additionally, included in this dissertation are four examples of science/engineering related inquiry-based lessons that were developed to relate well with my own Master's research field and implemented into three high school science and math classrooms over the course of a two year NSF STEM Fellowship. Lastly, a two-year long case study following qualitative and quantitative data from 296 students one of these activities provides examples of the positive impact by these types of developed activities.

Download or read book Using Mass Spectrometry and Ftir to Characterize Atmospherically relevant Particles Generated in Laboratory Systems written by Emily Anne Bruns and published by . This book was released on 2011 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric aerosols are known to have multifaceted effects on human health, visibility and climate. To understand these effects, characterization of aerosol properties is necessary. This dissertation focuses on several specific topics with the overall goal of improving our understanding of aerosols in the atmosphere. One area of importance is particulate organic nitrates, which are known to be ubiquitous in the atmosphere; however, there is a lack of proven analytical techniques for their measurement. The qualitative and quantitative response of a high resolution time of flight aerosol mass spectrometer to particulate organic nitrates was studied by analyzing secondary organic aerosol (SOA) from NO3 radical reactions with [Alpha]- and [Beta]-pinene, 3-carene, limonene, and isoprene. Extensive fragmentation of the organic nitrate products was observed in the mass spectra, which precluded molecular speciation. Another area of interest is the recent development of a number of ambient ionization techniques, which are promising for aerosol characterization. One such technique, atmospheric solids analysis probe mass spectrometry (ASAP-MS), was applied for the first time to the identification of organics in SOA, which was generated in the laboratory from the ozonolysis of & alpha;-pinene and isoprene, and from the NO3 oxidation of & alpha;-pinene. Also, ambient samples were collected from a forested and a suburban location. ASAP-MS data for the laboratory-generated samples showed peaks corresponding to well-known products of these reactions, and higher molecular weight oligomers were present in all samples. This is consistent with previously published studies of similar systems and shows that ASAP-MS should have wide applicability in both laboratory and field studies. Vapor pressures of low volatility compounds are important parameters in several atmospheric processes, including the formation of new particles and the partitioning of compounds between the gas-phase and particles. However, vapor pressures of low volatility compounds are challenging to measure and reported values vary significantly, illustrating the need for new approaches. ASAP-MS was applied for the first time to the measurement of vapor pressures and heats of sublimation. The measured heats of sublimation were in good agreement with published values. The vapor pressures were typically within a factor of three of published values made at similar temperatures. This study establishes that ASAP-MS is a promising new technique for vapor pressure and heat of sublimation measurements of low volatility compounds. To further understand new particle formation, laboratory and field measurements were made to identify gas-phase amines, which could play a role in new particle formation, from previously unknown sources using proton transfer reaction mass spectrometry. The work presented in this dissertation advances our understanding of aerosols and explores novel methods for their characterization.

Download or read book Development and Use of Particle Into Liquid Sampling Time of flight Mass Spectrometry PILS ToF for Characterization of Aerosol Particles written by Christopher Holmes Clark and published by . This book was released on 2012 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation introduces and makes use of the Particle-into-Liquid-Sampler coupled to a Time-of-Flight mass spectrometer (PILS-ToF), a new instrumental method used here to provide new chemical characterization information on secondary organic aerosol (SOA). The PILS-ToF instrument improves upon drawbacks found in current state-of-the-art mass spectral chemical characterization methods to include lack of time resolution and ion fragmentation by electron impact ionization in the Aerodyne Aerosol Mass Spectrometer (AMS). The functionality of the PILS-ToF for collection and response to SOA particle formation is validated against a scanning mobility particle sizer (SMPS), a widely accepted and standardized physical chemical characterization instrument, for a well characterized SOA formation experiment, dark ozonolysis of [alpja]-pinene. The PILS-ToF is also used to lend insight into oligomer growth during the NO photo-oxidation of isoprene. It is of atmospheric importance to study SOA formation from isoprene as it is globally the most abundant non-methane hydrocarbon in the ambient. SOA from isoprene is further studied using the PILS-ToF as part of the suite instrumentation at the University of California, Riverside, College of Engineering, Center for Environmental Research and Technology (CE-CERT) atmospheric chamber providing a complete chemical and physical characterization of SOA formed by isoprene with various oxidants under a myriad of oxidant concentration conditions. In addition, the PILS-ToF is used, again in tandem with other chemical and physical characterization methods at CE-CERT, to probe temperature effects on SOA formation from isoprene under many different oxidizing conditions. Finally, the PILS-ToF is used to provide new mechanistic information on SOA formation from trimethylamine and tributylamine, two tertiary amines emitted from anthropogenic and animal husbandry processes. For these two teriary amines the PILS-ToF provides evidence of oligomerization giving a potential explanation to the high SOA yields from these parent compounds.

Download or read book An Introduction to Time of Flight Secondary Ion Mass Spectrometry ToF SIMS and its Application to Materials Science written by Sarah Fearn and published by Morgan & Claypool Publishers. This book was released on 2015-10-16 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights the application of Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) for high-resolution surface analysis and characterization of materials. While providing a brief overview of the principles of SIMS, it also provides examples of how dual-beam ToF-SIMS is used to investigate a range of materials systems and properties. Over the years, SIMS instrumentation has dramatically changed since the earliest secondary ion mass spectrometers were first developed. Instruments were once dedicated to either the depth profiling of materials using high-ion-beam currents to analyse near surface to bulk regions of materials (dynamic SIMS), or time-of-flight instruments that produced complex mass spectra of the very outer-most surface of samples, using very low-beam currents (static SIMS). Now, with the development of dual-beam instruments these two very distinct fields now overlap.

Download or read book Quantitative Analysis of Aerosol Time of flight Mass Spectrometry Data Using YAADA written by Jonathan O. Allen and published by . This book was released on 2004 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of Soft Ionization for Particulate Organic Detection with the Aerodyne Aerosol Mass Spectrometer written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: During this DOE SBIR Phase II project, we have successfully developed several soft ionization techniques, i.e., ionization schemes which involve less fragmentation of the ions, for use with the Aerodyne time-of-flight aerosol mass spectrometer (ToF-AMS). Vacuum ultraviolet single photon ionization was demonstrated in the laboratory and deployed in field campaigns. Vacuum ultraviolet single photon ionization allows better identification of organic species in aerosol particles as shown in laboratory experiments on single component particles, and in field measurements on complex multi-component particles. Dissociative electron attachment with lower energy electrons (less than 30 eV) was demonstrated in the measurement of particulate organics in chamber experiments in Switzerland, and is now a routine approach with AMS systems configured for bipolar, negative ion detection. This technique is particularly powerful for detection of acidic and other highly oxygenated secondary organic aerosol (SOA) chemical functionality. Low energy electron ionization (10 to 12 eV) is also a softer ionization approach routinely available to AMS users. Finally, Lithium ion attachment has been shown to be sensitive to more alkyl-like chemical functionality in SOA. Results from Mexico City are particularly exciting in observing changes in SOA molecular composition under different photochemical/meteorological conditions. More recent results detecting biomass burns at the Montana fire lab have demonstrated quantitative and selective detection of levoglucosan. These soft ionization techniques provide the ToF-AMS with better capability for identifying organic species in ambient atmospheric aerosol particles. This, in turn, will allow more detailed study of the sources, transformations and fate of organic-containing aerosol.

Download or read book The Practice of TOF SIMS written by Alan M. Spool and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Time of flight secondary ion mass spectrometry, TOF-SIMS, is a highly surface sensitive analytical technique that can provide information about composition with submicron lateral resolution for a wide variety of materials. In conjunction with the latest cluster ion sources, organic depth profiling is also commonly performed now. For select materials, TOF-SIMS provides unparalleled sensitivity along with excellent reproducibility, and as a mass spectrometric technique, it also provides excellent specificity in the identification of many organic materials. Of the analytical methods available, it is among the most surface sensitive, but the physical principles that underlie it are also the least understood. This volume describes the instrumentation, the physical principles behind the technique to the extent they are understood, and provides a practical approach for the interpretation of TOF-SIMS data. The use of advanced data processing methods such as multivariate statistics are described in a readily approachable manner along with guidelines to help the reader understand where they are or are not really helpful. Given a basic background in undergraduate chemistry and physics, the book will be of use to any student with an interest in the technique. While the analyses are in fact performed in a vacuum, they are conducted in the context of a wider laboratory environment where many other analytical methods are available. The place of TOF-SIMS amongst them, when it is appropriate to use this method or another, or when multiple methods should be used in conjunction with TOF-SIMS is discussed in some depth. Examples of the wide range of applications of TOF-SIMS for research and problem solving in Academic Laboratories, National Laboratories, and Industrial laboratories, as it is applied to polymeric, biological, semiconductor, metallic, insulating, homogeneous, and inhomogeneous surfaces are described.

Download or read book Advances and Applications of Mass Spectral Techniques for the Characterization of Atmospheric Aerosol Particles written by Lindsay Erighn Hatch and published by . This book was released on 2012 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerosol particles are ubiquitous in the atmosphere and induce significant impacts on human health and climate that depend on their physical and chemical properties, such as size, composition, and mixing state (chemical associations). Measurements of aerosol composition at the single-particle level are necessary to better understand these effects. Aerosol time-of-flight mass spectrometry (ATOFMS) is able to monitor the size and chemical composition of individual particles in real time. In this doctoral research, ATOFMS analysis was extended to identify new mass spectral markers and improve the potential for quantitative measurements. Development of novel instrumentation was also undertaken. Ion markers indicative of organosulfate compounds were identified in ATOFMS mass spectra collected in Atlanta, GA. In this study, the mixing state and temporal behavior of particulate organosulfate compounds were observed for the first time. Organosulfates were overwhelmingly detected in carbonaceous submicron particles and the temporal trends indicated that they likely formed by the daytime oxidation of isoprene followed by aqueous reaction with sulfate overnight. These results highlight the roles of mixing state and multi-phase reactivity on the formation of secondary organic aerosols. ATOFMS measurements of thermally-conditioned aerosol residuals obtained during the 2005 Study of Organic Aerosols in Riverside, CA were analyzed to determine the impacts of atmospheric aging on the laser desorption/ionization process. Coatings of secondary species suppressed the ionization efficiency, thereby impacting the mass spectral peak areas; however, a novel analysis method was found to correct these artifacts and produced strong agreement with collocated quantitative instrumentation. This new analysis technique was then applied to investigate the mixing-state dependence of aerosol volatility observed in Riverside. It was observed that particulate nitrate evaporated at different temperatures from different particle types (e.g., organic vs. biomass burning), which may influence the regional transport of nitrate species. ATOFMS provides important insights into size-resolved particle sources; however it heavily fragments most organic species, resulting in loss of the molecular information. Therefore, a novel chemical ionization mass spectrometer was developed to better characterize the molecular organic aerosol constituents. In particular, an ion funnel was incorporated into a home-built proton-transfer-reaction mass spectrometer. Initial characterization studies and ion simulations indicated that the ion funnel can provide high-efficiency ion transfer from the ionization region to the mass spectrometer. These results demonstrate the potential for this instrument to ultimately achieve highly sensitive analyses of organic aerosols.

Download or read book A Molecular Characterization of Biogenic Secondary Organic Aerosol by High resolution Time of flight Mass Spectrometry written by Felipe Daniel Lopez-Hilfiker and published by . This book was released on 2015 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: The guiding question to this research is: To what extent and by what mechanisms do biogenic volatile organic compounds contribute to atmospheric aerosol mass? To address this question we need to understand the chemistry that produces condensable vapors which when in the presence of particles may partition onto the aerosol surface depending on their chemical and physical properties. I developed an insitu gas and aerosol sampling system, the FIGAERO (Filter Inlet for Gases and AEROsol) to speciate gas and particle phase organics derived from photochemical reactions with biogenic volatile organic compounds under both field and laboratory conditions. By coupling the FIGAERO to a High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (HR-TOF-CIMS) I am able to elucidate chemical pathways by identifying elemental compositions and in some cases functional groups present in the detected molecular ions. The coupling of the FIGAERO to the HR-TOF-CIMS also allows the estimation of effective vapor pressures of the aerosol components and this information can be used to improve vapor pressure models and test associated partitioning theories and parameterizations. The approach also provides hundreds of speciated chemical tracers that can be correlated with traditional environmental and chemical measurements (e.g AMS, NOx, SO2, SMPS, VOC) to help derive sources and sinks and to constrain the mechanisms responsible for the formation and growth of organic aerosol. Measurements obtained across a wide range of conditions and locations allowing connections and contrasts between different chemical systems, providing insights into generally controlling factors of secondary organic aerosol (SOA) and its properties.

Download or read book Fundamentals and Applications in Aerosol Spectroscopy written by Ruth Signorell and published by CRC Press. This book was released on 2010-12-20 with total page 513 pages. Available in PDF, EPUB and Kindle. Book excerpt: Helping you better understand the processes, instruments, and methods of aerosol spectroscopy, Fundamentals and Applications in Aerosol Spectroscopy provides an overview of the state of the art in this rapidly developing field. It covers fundamental aspects of aerosol spectroscopy, applications to atmospherically and astronomically relevant problem

Download or read book Characterization of Ambient Automobile and Diesel Aerosols Utilizing Aerosol Time of Flight Mass Spectrometry written by David Alan Sodeman and published by . This book was released on 2004 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Aerosol Particles Containing Sulfur and Nitrogen Species Using Aerosol Time of flight Mass Spectrometry ATOFMS written by Kimberly Louise Salt and published by . This book was released on 1995 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Deployment and Evaluation of an Aerosol Time of flight Mass Spectrometer written by Evelyn Jennifer Freney and published by . This book was released on 2006 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design and Characterization of a Time of flight Mass Spectrometer for Composition Measurements in the Upper Atmosphere written by E. Addison Everett and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In-situ composition measurements of the mesosphere/lower thermosphere (MLT) are challenging; this region is only accessible via high-speed sounding rockets, ambient pressures extend into the 10-3 Torr range, and particles of interest range in mass from electrons to meteoric smoke and dust particles. Time-of-flight mass spectrometers (TOF-MS) are capable of making fast, accurate measurements over a wide mass range. However, since they rely on pressure-sensitive microchannel plate (MCP) detectors and high voltages, they have rarely been applied at these altitudes. A new TOF-MS for making in-situ composition measurements in the MLT has been developed at the Space Dynamics Laboratory. This instrument employs modest acceleration potentials and a pressure-tolerant MCP detector. A Bradbury-Nielsen gate is used to produce short, well-defined ion pulses to reduce the temporal and spatial uncertainty of sampled ions. A prototype TOF-MS was constructed and used to demonstrate TOF-MS technology under conditions relevant to in-situ MLT measurements. Operational boundaries and capabilities of this new instrument were identified through laboratory experiments combined with computer modeling. The prototype instrument achieved a maximum resolution of 100 at m/z 40 (Ar), sufficient to resolve major atmospheric species of interest. During experiments at elevated pressures, the MCP detector maintained low background count rates (/second) at pressures as high as 10-3 Torr. A novel getter-based vacuum system was evaluated for use with the new TOF-MS, and a computer model was developed to simulate instrument pressure during a rocket flight. Results from these experiments suggest that when combined with an appropriately sized sampling aperture, this pumping system can extend the measurement range of the instrument to lower altitudes by 10 0́3 20 km, compared to an unpumped instrument. A computer model was developed to study the effects of critical operating parameters on instrument performance; the most important factor affecting resolution was found to be the initial energy spread of sampled ions. Sensitivity and number density measurement analyses suggest the new instrument will measure major species in the MLT at better than 10% uncertainty. Composition measurements made with the new TOF-MS will contribute to a better understanding of the MLT.

Download or read book Aerosol Time of flight Mass Spectrometry ATOFMS as a Real time Monitor of Individual Aerosol Particles in Field Studies written by Kimberly A. Prather and published by . This book was released on 2001 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: