The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Kimberly A Prather - One of the best experts on this subject based on the ideXlab platform.
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a comparison of Particle Mass spectrometers during the 1999 atlanta supersite project
Journal of Geophysical Research, 2003Co-Authors: Ann M. Middlebrook, Ryan J Wenzel, Denis J Phares, Kimberly A Prather, D M Murphy, D.s. ThomsonAbstract:During the Atlanta Supersite Project, four Particle Mass spectrometers were operated together for the first time: NOAA's Particle Analysis by Laser Mass Spectrometer (PALMS), University of California at Riverside's Aerosol Time-of-Flight Mass Spectrometer (ATOFMS), University of Delaware's Rapid Single-Particle Mass Spectrometer II (RSMS-II), and Aerodyne's Aerosol Mass Spectrometer (AMS). Although these Mass spectrometers are generally classified as similar instruments, they clearly have different characteristics due to their unique designs. One primary difference is related to the volatilization/ionization method: PALMS, ATOFMS, and RSMS-II utilize laser desorption/ionization, whereas Particles in the AMS instrument are volatilized by impaction onto a heated surface with the resulting components ionized by electron impact. Thus Mass spectral data from the AMS are representative of the ensemble of Particles sampled, and those from the laser-based instruments are representative of individual Particles. In addition, the AMS instrument cannot analyze refractory material such as soot, sodium chloride, and crustal elements, and some sulfate or water-rich Particles may not always be analyzed with every laser-based instrument. A main difference among the laser-based Mass spectrometers is that the RSMS-II instrument can obtain size-resolved single Particle composition information for Particles with aerodynamic diameters as small as 15 nm. The minimum sizes analyzed by ATOFMS and PALMS are 0.2 and about 0.35 μm, respectively, in aerodynamic diameter. Furthermore, PALMS, ATOFMS, and RSMS-II use different laser ionization conditions. Despite these differences the laser-based instruments found similar individual Particle classifications, and their relative fractions among comparable sized Particles from Atlanta were broadly consistent. Finally, the AMS measurements of the nitrate/sulfate mole ratio were highly correlated with composite measurements (r^2 = 0.93). In contrast, the PALMS nitrate/sulfate ion ratios were only moderately correlated (r^2 ∼ 0.7).
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real time single Particle Mass spectrometry a historical review of a quarter century of the chemical analysis of aerosols
Mass Spectrometry Reviews, 2000Co-Authors: Christopher A Noble, Kimberly A PratherAbstract:Real-time single Particle Mass spectrometry, or continuous aerosol Mass spectrometry, was originally developed in the 1970s for the purpose of identifying the chemical composition of airborne particulate matter in real-time. Although this technique has continued to evolve throughout the following decades, the fundamental characteristic of this method remains the same, involving the continuous introduction of solid Particle or liquid droplets directly into the ion source region of a Mass spectrometer. Continuous sample introduction allows for the chemical analysis of single airborne Particles in real-time. A number of Mass analyzers have been employed in real-time single Particle Mass spectrometry. The original real-time single Particle Mass spectrometer used a magnetic sector Mass analyzer. Quadrupole, double-focusing, and ion trap Mass spectrometers have also been utilized. The majority of the current real-time single Particle Mass spectrometry techniques use time-of-flight Mass spectrometry. In the literature, a variety of general names have been applied to real-time single Particle Mass spectrometry methods. These names include direct-inlet Mass spectrometry, on-line laser microprobe Mass spectrometry, Particle analysis by Mass spectrometry, Particle beam Mass spectrometry, and rapid-single Particle Mass spectrometry. This review covers real-time single Particle Mass spectrometry techniques that were developed from 1973 through 1998, specifically for analyzing airborne particulate matter, including environmental aerosols, biological aerosols, and clean-room aerosols. Because the majority of the historical and current real-time single Particle Mass spectrometers have been employed for atmospheric aerosols, this topic is the primary focus of this review. This review does not include on-line Mass spectrometry methods that are employed as a detector for other instrumental methods, such as liquid chromatography. © 2000 John Wiley & Sons, Inc., Mass Spec Rev 19: 248–274, 2000
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Real‐time single Particle Mass spectrometry: A historical review of a quarter century of the chemical analysis of aerosols
Mass spectrometry reviews, 2000Co-Authors: Christopher A Noble, Kimberly A PratherAbstract:Real-time single Particle Mass spectrometry, or continuous aerosol Mass spectrometry, was originally developed in the 1970s for the purpose of identifying the chemical composition of airborne particulate matter in real-time. Although this technique has continued to evolve throughout the following decades, the fundamental characteristic of this method remains the same, involving the continuous introduction of solid Particle or liquid droplets directly into the ion source region of a Mass spectrometer. Continuous sample introduction allows for the chemical analysis of single airborne Particles in real-time. A number of Mass analyzers have been employed in real-time single Particle Mass spectrometry. The original real-time single Particle Mass spectrometer used a magnetic sector Mass analyzer. Quadrupole, double-focusing, and ion trap Mass spectrometers have also been utilized. The majority of the current real-time single Particle Mass spectrometry techniques use time-of-flight Mass spectrometry. In the literature, a variety of general names have been applied to real-time single Particle Mass spectrometry methods. These names include direct-inlet Mass spectrometry, on-line laser microprobe Mass spectrometry, Particle analysis by Mass spectrometry, Particle beam Mass spectrometry, and rapid-single Particle Mass spectrometry. This review covers real-time single Particle Mass spectrometry techniques that were developed from 1973 through 1998, specifically for analyzing airborne particulate matter, including environmental aerosols, biological aerosols, and clean-room aerosols. Because the majority of the historical and current real-time single Particle Mass spectrometers have been employed for atmospheric aerosols, this topic is the primary focus of this review. This review does not include on-line Mass spectrometry methods that are employed as a detector for other instrumental methods, such as liquid chromatography. © 2000 John Wiley & Sons, Inc., Mass Spec Rev 19: 248–274, 2000
Christopher A Noble - One of the best experts on this subject based on the ideXlab platform.
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real time single Particle Mass spectrometry a historical review of a quarter century of the chemical analysis of aerosols
Mass Spectrometry Reviews, 2000Co-Authors: Christopher A Noble, Kimberly A PratherAbstract:Real-time single Particle Mass spectrometry, or continuous aerosol Mass spectrometry, was originally developed in the 1970s for the purpose of identifying the chemical composition of airborne particulate matter in real-time. Although this technique has continued to evolve throughout the following decades, the fundamental characteristic of this method remains the same, involving the continuous introduction of solid Particle or liquid droplets directly into the ion source region of a Mass spectrometer. Continuous sample introduction allows for the chemical analysis of single airborne Particles in real-time. A number of Mass analyzers have been employed in real-time single Particle Mass spectrometry. The original real-time single Particle Mass spectrometer used a magnetic sector Mass analyzer. Quadrupole, double-focusing, and ion trap Mass spectrometers have also been utilized. The majority of the current real-time single Particle Mass spectrometry techniques use time-of-flight Mass spectrometry. In the literature, a variety of general names have been applied to real-time single Particle Mass spectrometry methods. These names include direct-inlet Mass spectrometry, on-line laser microprobe Mass spectrometry, Particle analysis by Mass spectrometry, Particle beam Mass spectrometry, and rapid-single Particle Mass spectrometry. This review covers real-time single Particle Mass spectrometry techniques that were developed from 1973 through 1998, specifically for analyzing airborne particulate matter, including environmental aerosols, biological aerosols, and clean-room aerosols. Because the majority of the historical and current real-time single Particle Mass spectrometers have been employed for atmospheric aerosols, this topic is the primary focus of this review. This review does not include on-line Mass spectrometry methods that are employed as a detector for other instrumental methods, such as liquid chromatography. © 2000 John Wiley & Sons, Inc., Mass Spec Rev 19: 248–274, 2000
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Real‐time single Particle Mass spectrometry: A historical review of a quarter century of the chemical analysis of aerosols
Mass spectrometry reviews, 2000Co-Authors: Christopher A Noble, Kimberly A PratherAbstract:Real-time single Particle Mass spectrometry, or continuous aerosol Mass spectrometry, was originally developed in the 1970s for the purpose of identifying the chemical composition of airborne particulate matter in real-time. Although this technique has continued to evolve throughout the following decades, the fundamental characteristic of this method remains the same, involving the continuous introduction of solid Particle or liquid droplets directly into the ion source region of a Mass spectrometer. Continuous sample introduction allows for the chemical analysis of single airborne Particles in real-time. A number of Mass analyzers have been employed in real-time single Particle Mass spectrometry. The original real-time single Particle Mass spectrometer used a magnetic sector Mass analyzer. Quadrupole, double-focusing, and ion trap Mass spectrometers have also been utilized. The majority of the current real-time single Particle Mass spectrometry techniques use time-of-flight Mass spectrometry. In the literature, a variety of general names have been applied to real-time single Particle Mass spectrometry methods. These names include direct-inlet Mass spectrometry, on-line laser microprobe Mass spectrometry, Particle analysis by Mass spectrometry, Particle beam Mass spectrometry, and rapid-single Particle Mass spectrometry. This review covers real-time single Particle Mass spectrometry techniques that were developed from 1973 through 1998, specifically for analyzing airborne particulate matter, including environmental aerosols, biological aerosols, and clean-room aerosols. Because the majority of the historical and current real-time single Particle Mass spectrometers have been employed for atmospheric aerosols, this topic is the primary focus of this review. This review does not include on-line Mass spectrometry methods that are employed as a detector for other instrumental methods, such as liquid chromatography. © 2000 John Wiley & Sons, Inc., Mass Spec Rev 19: 248–274, 2000
Scot T. Martin - One of the best experts on this subject based on the ideXlab platform.
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Particle Mass yield from β -caryophyllene ozonolysis
Atmospheric Chemistry and Physics, 2012Co-Authors: Qi Chen, Karena A. Mckinney, Mikinori Kuwata, Scot T. MartinAbstract:Abstract. The influence of second-generation products on the Particle Mass yield of β-caryophyllene ozonolysis was systematically tested and quantified. The approach was to vary the relative concentrations of first- and second-generation products by adjusting the concentration of ozone while observing changes in Particle Mass yield. For all wall-loss corrected organic Particle Mass concentrations Morg of this study (0.5 10 μg m−3 the Particle Mass yield increased to as high as 70% for the ultimate yield corresponding to the greatest ozone exposures. These differing dependencies on ozone exposure under different regimes of Morg are explained by a combination of the ozonolysis lifetimes of the first-generation products and the volatility distribution of the resulting second-generation products. First-generation products that have short lifetimes produce low-volatility second-generation products whereas first-generation products that have long lifetimes produce high-volatility second-generation products. The ultimate Particle Mass yield was defined by Mass-based stoichiometric yields αi of α0 = 0.17 ± 0.05, α1 = 0.11 ± 0.17, and α2 = 1.03 ± 0.30 for corresponding saturation concentrations of 1, 10, and 100 μg m−3. Terms α0 and α1 had low sensitivity to the investigated range of ozone exposure whereas term α2 increased from 0.32 ± 0.13 to 1.03 ± 0.30 as the ozone exposure was increased. These findings potentially allow for simplified yet accurate parameterizations in air quality and climate models that seek to represent the ozonolysis Particle Mass yields of certain classes of biogenic compounds.
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Particle Mass yield from <i>β</i>-caryophyllene ozonolysis
2011Co-Authors: Qi Chen, Karena A. Mckinney, Mikinori Kuwata, Scot T. MartinAbstract:Abstract. The influence of second-generation products on the Particle Mass yield of β-caryophyllene ozonolysis was systematically tested and quantified. The approach was to vary the relative concentrations of first- and second-generation products by controlling ozone concentration, while observing the change in Particle Mass yield. For all organic Particle Mass concentrations Morg of this study (0.5 < Morg < 230 μg m−3), the data show that Particle-phase organic material was in large part composed of second-generation products. For 0.5 < Morg <10 μg m−3, a range which overlaps with atmospheric concentrations, the Particle Mass yield was not sensitive to ozone exposure, implying that the constituent molecules were rapidly produced at all investigated ozone exposures. In contrast, for Morg > 10 μg m−3 the Particle Mass yield increased with ozone exposure. These different dependencies on ozone exposure with M org are explained by a combination of the ozonolysis lifetimes of the first-generation products and the volatility distribution of the resulting second-generation products. First-generation products that have short lifetimes produce low-volatility second-generation products whereas first-generation products that have long lifetimes produce high-volatility second-generation products. The ultimate Particle Mass yield was defined by Mass-based stoichiometric yields α0 = 0.17 ± 0.05, α1 = 0.11 ± 0.17, and α2 = 1.03 ± 0.30 for corresponding saturation concentrations of 1, 10, and 100 μg m−3. Terms α0 and α1 had low sensitivity to the investigated range of ozone exposure whereas term α2 increased from 0.32 ± 0.13 to 1.03 ± 0.30 as the ozone exposure was increased. These findings potentially allow for simplified yet nevertheless accurate parameterizations in air quality and climate models that seek to represent the ozonolysis Particle Mass yield of certain classes of biogenic compounds.
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Particle Mass yield in secondary organic aerosol formed by the dark ozonolysis of ?-pinene
Atmospheric Chemistry and Physics, 2008Co-Authors: J. E. Shilling, Qi Chen, Karena A. Mckinney, S. M. King, T. Rosenoern, J. H. Kroll, D. R. Worsnop, Scot T. MartinAbstract:The yield of Particle Mass in secondary organic aerosol (SOA) formed by dark ozonolysis was measured for 0.3?22.8 ppbv of reacted ?-pinene. Most experiments were conducted using a continuous-flow chamber, allowing nearly constant SOA concentration and chemical composition for several days. For comparison, some experiments were also conducted in batch mode. Reaction conditions were 25°C, 40% RH, dry (NH4)SO4 seed Particles, and excess 1-butanol. The organic Particle loading was independently measured by an aerosol Mass spectrometer and a scanning mobility Particle sizer, and the two measurements agreed well. The observations showed that SOA formation occurred for even the lowest reacted ?-pinene concentration of 0.3 ppbv. The Particle Mass yield was 0.09 at 0.15 ?g m?3, increasing to 0.27 at 40 ?g m?3. Compared to some results reported in the literature, the yields were 80 to 100% larger for loadings above 2 ?g m?3. At lower loadings, the yields had an offset of approximately +0.07 from those reported in the literature. To as low as 0.15 ?m?3, the yield curve had no inflection point toward null yield, implying the formation of one or several products having vapor pressures below this value. These observations of increased yields, especially for low loadings, are potentially important for accurate prediction by chemical transport models of organic Particle concentrations in the ambient atmosphere.
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Particle Mass yield in secondary organic aerosol formed by the dark ozonolysis of ?-pinene
Atmospheric Chemistry and Physics Discussions, 2007Co-Authors: J. E. Shilling, Qi Chen, Karena A. Mckinney, S. M. King, T. Rosenoern, J. H. Kroll, D. R. Worsnop, Scot T. MartinAbstract:The yield of Particle Mass in secondary organic aerosol (SOA) formed by dark ozonolysis was measured for 0.3?22.8 ppbv of reacted ?-pinene. Most experiments were conducted using a continuous-flow chamber, allowing nearly constant SOA concentration and chemical composition for several days. For comparison, some experiments were also conducted in batch mode. Reaction conditions were 25°C, 40% RH, dry (NH)4SO4 seed Particles, and excess 1-butanol. The organic Particle loading was independently measured by an aerosol Mass spectrometer and a scanning mobility Particle sizer, and the two measurements agreed well. The observations showed that SOA formation occurred for even the lowest reacted ?-pinene concentration of 0.3 ppbv. The Particle Mass yield was 0.09 at 0.15 ?g m?3, increasing to 0.27 at 40 ?g m?3. Compared to results reported in the literature, the yields were 80 to 100% larger for loadings above 2 ?g m?3. At lower loadings, the yields had an offset of approximately +0.07 from those reported in the literature. To as low as 0.15 ?g m?3, the yield curve had no inflection point toward null yield, implying the formation of one or several products having vapor pressures below this value. These observations of increased yields, especially for low loadings, are potentially important for accurate prediction by chemical transport models of organic Particle concentrations in the ambient atmosphere.
S C Russell - One of the best experts on this subject based on the ideXlab platform.
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Microorganism characterization by single Particle Mass spectrometry
Mass spectrometry reviews, 2009Co-Authors: S C RussellAbstract:In recent years a major effort by several groups has been undertaken to identify bacteria by Mass spectrometry at the single cell level. The intent of this review is to highlight the recent progress made in the application of single Particle Mass spectrometry to the analysis of microorganisms. A large portion of the review highlights improvements in the ionization and Mass analysis of bio-aerosols, or Particles that contain biologically relevant molecules such as peptides or proteins. While these are not direct applications to bacteria, the results have been central to a progression toward single cell Mass spectrometry. Developments in single Particle matrix-assisted laser desorption/ionization (MALDI) are summarized. Recent applications of aerosol laser desorption/ionization (LDI) to the analysis of single microorganisms are highlighted. Successful applications of off-line and on-the-fly aerosol MALDI to microorganism detection are discussed. Limitations to current approaches and necessary future achievements are also addressed.
Donggeun Lee - One of the best experts on this subject based on the ideXlab platform.
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An ion optics for effective ion detection in single Particle Mass spectrometry.
Rapid communications in mass spectrometry : RCM, 2007Co-Authors: Sung-woo Cho, Donggeun LeeAbstract:Recently, we reported that significant ion loss occurs prior to detection in conventional single Particle Mass spectrometry. A more serious type of loss is ion-kinetic-energy-dependent loss. This leads to significant errors in the measured chemical composition of nanoParticles, especially when they have a core-shell structure. In this paper, a novel ion optics for effective detection of ions generated from a single nanoParticle is designed. Using the commercial software SIMION, the trajectories of ions launched at different speeds inside a single Particle Mass spectrometer are simulated. The effects of changes are investigated with different repelling plates, Einzel lens additions, and substitutions of the tube electrode between extraction and acceleration grids on the ion flight. The best design was found when assembling the trials in the present condition. It was demonstrated experimentally that the new ion optics works well not only in theory, but also in practice.
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measurement of condensed phase reaction kinetics in the aerosol phase using single Particle Mass spectrometry
Journal of Physical Chemistry A, 2002Co-Authors: R Mahadevan, Donggeun Lee, H Sakurai, Michael R ZachariahAbstract:We applied a recently developed single Particle Mass spectrometer to analyze the elemental composition of individual aerosol Particles and applied the technique to study the kinetics of thermal decomposition of metal nitrate aerosols (aluminum, calcium, silver, and strontium). Such decomposition processes on the industrial scale is known as spray pyrolysis and is a common method for making metal and metal oxide Particles. Metal nitrate aerosols were passed through a tube furnace to induce thermal decomposition and transformation into oxides, and were delivered with high efficiency into the vacuum system of the single Particle Mass spectrometer using an aerodynamics lens arrangement. The Particles were ablated and torn down to atomic ions with a tightly focused, high-power pulsed laser in the extraction field of the time-of-flight Mass spectrometer. The Mass spectra thus obtained are shown to carry a quantitative signature of the elemental composition of individual Particles, and allow for on-line measurem...