WorldWideScience

Sample records for aerosol mass spectrometry

  1. Identification of secondary organic aerosols based on aerosol mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Secondary organic aerosol (SOA) is one of the major components of aerosols in the atmosphere and has not been well understood so far.Due to the complex chemical composition of organic aerosols,the identification of SOA has been a hotspot and difficult issue in the field of aerosol study.This study attempts to quantitatively identify SOA in winter of Shenzhen based on positive matrix factorization (PMF) analysis.Major sources were resolved and SOA was identified subsequently according to the characteristic ion fragments measured by highly time-resolved aerosol mass spectrometer measurement.It showed that in the winter of Shenzhen the average SOA concentration was 9.41±6.33 g/m 3,accounting for 39.9±21.8% of the total organic mass.Compared with primary organic aerosol (POA),the SOA concentrations had no large variation,suggestive of characteristics of regional secondary pollutants.The ratio of SOA/BC had pronounced diurnal variation,similar to that of O x (O3+NO2),indicating SOA formation was significantly controlled by activity of photochemistry in the atmosphere.The most effective period for SOA formation was from 9 am~3 pm since the SOA/BC ratio increased by 122% during this period.This study provides a new technical method and a new idea for SOA investigation.

  2. Aerosol mass spectrometry systems and methods

    Science.gov (United States)

    Fergenson, David P.; Gard, Eric E.

    2013-08-20

    A system according to one embodiment includes a particle accelerator that directs a succession of polydisperse aerosol particles along a predetermined particle path; multiple tracking lasers for generating beams of light across the particle path; an optical detector positioned adjacent the particle path for detecting impingement of the beams of light on individual particles; a desorption laser for generating a beam of desorbing light across the particle path about coaxial with a beam of light produced by one of the tracking lasers; and a controller, responsive to detection of a signal produced by the optical detector, that controls the desorption laser to generate the beam of desorbing light. Additional systems and methods are also disclosed.

  3. Characterization of urban aerosol in Cork City (Ireland using aerosol mass spectrometry

    Directory of Open Access Journals (Sweden)

    M. Dall'Osto

    2012-11-01

    Full Text Available Ambient wintertime background urban aerosol in Cork City, Ireland, was characterized using aerosol mass spectrometry. During the three-week measurement study in 2009, 93% of the 1 200 000 single particles characterized by an Aerosol Time-Of-Flight Mass Spectrometer (TSI ATOFMS were classified into five organic-rich particle types, internally-mixed to different proportions with Elemental Carbon (EC, sulphate and nitrate while the remaining 7% was predominantly inorganic in nature. Non-refractory PM1 aerosol was also characterized using a High Resolution Time-Of-Flight Aerodyne Aerosol Mass Spectrometer (HR-ToF-AMS and was also found to comprise organic matter as the most abundant species (62%, followed by nitrate (15%, sulphate (9% and ammonium (9%, and then chloride (5%.

    Positive matrix factorization (PMF was applied to the HR-ToF-AMS organic matrix and a five-factor solution was found to describe the variance in the data well. Specifically, "Hydrocarbon-like" Organic Aerosol (HOA comprised 19% of the mass, "Oxygenated low volatility" Organic Aerosols (LV-OOA comprised 19%, "Biomass wood Burning" Organic Aerosol (BBOA comprised 23%, non-wood solid-fuel combustion "Peat and Coal" Organic Aerosol (PCOA comprised 21%, and finally, a species type characterized by primary m/z peaks at 41 and 55, similar to previously-reported "Cooking" Organic Aerosol (COA but possessing different diurnal variations to what would be expected for cooking activities, contributed 18%. Despite wood, cool and peat being minor fuel types used for domestic space heating in urban areas, their relatively low combustion efficiencies result in a significant contribution to PM1 aerosol mass (44% and 28% of the total organic aerosols mass and non refractory PM1, respectively.

  4. Bio-Aerosol Detection Using Mass Spectrometry: Public Health Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ludvigson, Laura D. [Univ. of California, Berkeley, CA (United States)

    2004-01-01

    I recently spent a summer as an intern at the Lawrence Livermore National Laboratory. I worked on a project involving the real-time, reagentless, single cell detection of aerosolized pathogens using a novel mass spectrometry approach called Bio-Aerosol Mass Spectrometry (BAMS). Based upon preliminary results showing the differentiation capabilities of BAMS, I would like to explore the development and use of this novel detection system in the context of both environmental and clinical sample pathogen detection. I would also like to explore the broader public health applications that a system such as BAMS might have in terms of infectious disease prevention and control. In order to appreciate the potential of this instrument, I will demonstrate the need for better pathogen detection methods, and outline the instrumentation, data analysis and preliminary results that lead me toward a desire to explore this technology further. I will also discuss potential experiments for the future along with possible problems that may be encountered along the way.

  5. Bio-Aerosol Detection Using Mass Spectrometry: Public Health Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ludvigson, L D

    2004-03-05

    I recently spent a summer as an intern at the Lawrence Livermore National Laboratory. I worked on a project involving the real-time, reagentless, single cell detection of aerosolized pathogens using a novel mass spectrometry approach called Bio-Aerosol Mass Spectrometry (BAMS). Based upon preliminary results showing the differentiation capabilities of BAMS, I would like to explore the development and use of this novel detection system in the context of both environmental and clinical sample pathogen detection. I would also like to explore the broader public health applications that a system such as BAMS might have in terms of infectious disease prevention and control. In order to appreciate the potential of this instrument, I will demonstrate the need for better pathogen detection methods, and outline the instrumentation, data analysis and preliminary results that lead me toward a desire to explore this technology further. I will also discuss potential experiments for the future along with possible problems that may be encountered along the way.

  6. Characterization of ambient aerosols at the San Francisco International Airport using BioAerosol Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Steele, P T; McJimpsey, E L; Coffee, K R; Fergenson, D P; Riot, V J; Tobias, H J; Woods, B W; Gard, E E; Frank, M

    2006-03-16

    The BioAerosol Mass Spectrometry (BAMS) system is a rapidly fieldable, fully autonomous instrument that can perform correlated measurements of multiple orthogonal properties of individual aerosol particles. The BAMS front end uses optical techniques to nondestructively measure a particle's aerodynamic diameter and fluorescence properties. Fluorescence can be excited at 266nm or 355nm and is detected in two broad wavelength bands. Individual particles with appropriate size and fluorescence properties can then be analyzed more thoroughly in a dual-polarity time-of-flight mass spectrometer. Over the course of two deployments to the San Francisco International Airport, more than 6.5 million individual aerosol particles were fully analyzed by the system. Analysis of the resulting data has provided a number of important insights relevant to rapid bioaerosol detection, which are described here.

  7. The on-line analysis of aerosol-delivered pharmaceuticals via single particle aerosol mass spectrometry.

    Science.gov (United States)

    Morrical, Bradley D; Balaxi, Maria; Fergenson, David

    2015-07-15

    The use of single particle aerosol mass spectrometry (SPAMS) was evaluated for the analysis of inhaled pharmaceuticals to determine the mass distribution of the individual active pharmaceutical ingredients (API) in both single ingredient and combination drug products. SPAMS is an analytical technique where the individual aerodynamic diameters and chemical compositions of many aerosol particles are determined in real-time. The analysis was performed using a Livermore Instruments SPAMS 3.0, which allowed the efficient analysis of aerosol particles with broad size distributions and can acquire data even under a very large particle load. Data similar to what would normally require roughly three days of experimentation and analysis was collected in a five minute period and analyzed automatically. The results were computed to be comparable to those returned by a typical Next Generation Impactor (NGI) particle size distribution experiment.

  8. Aerosol Analysis via Electrostatic Precipitation-Electrospray Ionization Mass Spectrometry.

    Science.gov (United States)

    He, Siqin; Li, Lin; Duan, Hongxu; Naqwi, Amir; Hogan, Christopher J

    2015-07-01

    Electrospray ionization (ESI) is the preferred mode of ion generation for mass analysis of many organic species, as alternative ionization techniques can lead to appreciable analyte fragmentation. For this reason, ESI is an ideal method for the analysis of species within aerosol particles. However, because of their low concentrations (∼10 μg/m(3)) in most environments, ESI has been applied sparingly in aerosol particle analysis; aerosol mass spectrometers typically employ analyte volatilization followed by electron ionization or chemical ionization, which can lead to a considerable degree of analyte fragmentation. Here, we describe an approach to apply ESI to submicrometer and nanometer scale aerosol particles, which utilizes unipolar ionization to charge particles, electrostatic precipitation to collect particles on the tip of a Tungsten rod, and subsequently, by flowing liquid over the rod, ESI and mass analysis of the species composing collected particles. This technique, which we term electrostatic precipitation-ESI-MS (EP-ESI-MS), is shown to enable analysis of nanogram quantities of collected particles (from aerosol phase concentrations as low as 10(2) ng m(-3)) composed of cesium iodide, levoglucosan, and levoglucosan within a carbon nanoparticle matrix. With EP-ESI-MS, the integrated mass spectrometric signals are found to be a monotonic function of the mass concentration of analyte in the aerosol phase. We additionally show that EP-ESI-MS has a dynamic range of close to 5 orders of magnitude in mass, making it suitable for molecular analysis of aerosol particles in laboratory settings with upstream particle size classification, as well as analysis of PM 2.5 particles in ambient air. PMID:26024017

  9. Aerosol detection efficiency in inductively coupled plasma mass spectrometry

    Science.gov (United States)

    Hubbard, Joshua A.; Zigmond, Joseph A.

    2016-05-01

    An electrostatic size classification technique was used to segregate particles of known composition prior to being injected into an inductively coupled plasma mass spectrometer (ICP-MS). Size-segregated particles were counted with a condensation nuclei counter as well as sampled with an ICP-MS. By injecting particles of known size, composition, and aerosol concentration into the ICP-MS, efficiencies of the order of magnitude aerosol detection were calculated, and the particle size dependencies for volatile and refractory species were quantified. Similar to laser ablation ICP-MS, aerosol detection efficiency was defined as the rate at which atoms were detected in the ICP-MS normalized by the rate at which atoms were injected in the form of particles. This method adds valuable insight into the development of technologies like laser ablation ICP-MS where aerosol particles (of relatively unknown size and gas concentration) are generated during ablation and then transported into the plasma of an ICP-MS. In this study, we characterized aerosol detection efficiencies of volatile species gold and silver along with refractory species aluminum oxide, cerium oxide, and yttrium oxide. Aerosols were generated with electrical mobility diameters ranging from 100 to 1000 nm. In general, it was observed that refractory species had lower aerosol detection efficiencies than volatile species, and there were strong dependencies on particle size and plasma torch residence time. Volatile species showed a distinct transition point at which aerosol detection efficiency began decreasing with increasing particle size. This critical diameter indicated the largest particle size for which complete particle detection should be expected and agreed with theories published in other works. Aerosol detection efficiencies also displayed power law dependencies on particle size. Aerosol detection efficiencies ranged from 10- 5 to 10- 11. Free molecular heat and mass transfer theory was applied, but

  10. Organic aerosol mixing observed by single-particle mass spectrometry.

    Science.gov (United States)

    Robinson, Ellis Shipley; Saleh, Rawad; Donahue, Neil M

    2013-12-27

    We present direct measurements of mixing between separately prepared organic aerosol populations in a smog chamber using single-particle mass spectra from the high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). Docosane and docosane-d46 (22 carbon linear solid alkane) did not show any signs of mixing, but squalane and squalane-d62 (30 carbon branched liquid alkane) mixed on the time scale expected from a condensational-mixing model. Docosane and docosane-d46 were driven to mix when the chamber temperature was elevated above the melting point for docosane. Docosane vapors were shown to mix into squalane-d62, but not the other way around. These results are consistent with low diffusivity in the solid phase of docosane particles. We performed mixing experiments on secondary organic aerosol (SOA) surrogate systems finding that SOA derived from toluene-d8 (a surrogate for anthropogenic SOA (aSOA)) does not mix into squalane (a surrogate for hydrophobic primary organic aerosol (POA)) but does mix into SOA derived from α-pinene (biogenic SOA (bSOA) surrogate). For the aSOA/POA, the volatility of either aerosol does not limit gas-phase diffusion, indicating that the two particle populations do not mix simply because they are immiscible. In the aSOA/bSOA system, the presence of toluene-d8-derived SOA molecules in the α-pinene-derived SOA provides evidence that the diffusion coefficient in α-pinene-derived SOA is high enough for mixing on the time scale of 1 min. The observations from all of these mixing experiments are generally invisible to bulk aerosol composition measurements but are made possible with single-particle composition data.

  11. Characterization of aerosol chemical composition with aerosol mass spectrometry in Central Europe: an overview

    Directory of Open Access Journals (Sweden)

    V. A. Lanz

    2010-11-01

    Full Text Available Real-time measurements of non-refractory submicron aerosols (NR-PM1 were conducted within the greater Alpine region (Switzerland, Germany, Austria, France and Liechtenstein during several week-long field campaigns in 2002–2009. This region represents one of the most important economic and recreational spaces in Europe. A large variety of sites was covered including urban backgrounds, motorways, rural, remote, and high-alpine stations, and also mobile on-road measurements were performed. Inorganic and organic aerosol (OA fractions were determined by means of aerosol mass spectrometry (AMS. The data originating from 13 different field campaigns and the combined data have been utilized for providing an improved temporal and spatial data coverage.

    The average mass concentration of NR-PM1 for the different campaigns typically ranged between 10 and 30 μg m−3. Overall, the organic portion was most abundant, ranging from 36% to 81% of NR-PM1. Other main constituents comprised ammonium (5–15%, nitrate (8–36%, sulfate (3–26%, and chloride (0–5%. These latter anions were, on average, fully neutralized by ammonium. As a major result, time of the year (winter vs. summer and location of the site (Alpine valleys vs. Plateau could largely explain the variability in aerosol chemical composition for the different campaigns and were found to be better descriptors for aerosol composition than the type of site (urban, rural etc.. Thus, a reassessment of classifications of measurements sites might be considered in the future, possibly also for other regions of the world.

    The OA data was further analyzed using positive matrix factorization (PMF and the multi-linear engine ME (factor analysis separating the total OA into its underlying components, such as oxygenated (mostly secondary organic aerosol (OOA, hydrocarbon-like and freshly emitted organic aerosol (HOA, as well as OA from biomass

  12. Mass spectrometry investigation of Titan aerosols analogs formed with traces of aromatic compounds

    Science.gov (United States)

    Gautier, Thomas; Trainer, Melissa; Sebree, Joshua; Li, Xiang; Pinnick, Veronica; Getty, Stephanie; Brinckerhoff, Will

    2016-06-01

    The detection of benzene at ppm levels in Titan's atmosphere [1] by Cassini's Ion and Neutral Mass Spectrometer (INMS) supports the idea that aromatic and heteroaromatic reaction pathways may play an important role in Titan's aerosols formation. In laboratory studies it has been shown that these aromatic molecules are easily dissociated by ultraviolet radiation and can therefore contribute significantly to aerosol formation [2] and be used to dope the production of aerosol analogs [3]. In this work we investigate the effect on the aerosol composition and growth pattern of the chemical nature of the aromatic reactant used to produce aerosol. Analysis are performed using Laser Desorption-Time of Flight mass spectrometry (LD-TOF) and Fourier Transform Infrared Spectroscopy (FTIR) Infrared analysis of our samples shows that inclusion of aromatic compounds as trace precursors allows to better fit laboratory data to Titan aerosol spectra observed by Cassini [3,4]. The improvement is especially visible on the far infrared (˜200 cm-1) bands observed by CIRS [5]. LDMS results show that the aerosol growth patterns depend both on the number of rings and on the nitrogen content of the trace precursor used. We also perform MS/MS analysis on some prominent peaks of aerosol mass spectra. This MS/MS approach allows us to identify some of the key compounds in the aerosol growth processes.

  13. Unraveling the Complexity of Atmospheric Aerosol: Insights from Ultrahigh Resolution Mass Spectrometry

    Science.gov (United States)

    Mazzoleni, Lynn R.; Zhao, Yunzhu; Samburova, Vera; Gannet Hallar, A.; Lowenthal, Douglas

    2016-04-01

    Atmospheric aerosol organic matter (AOM) is a complex mixture of thousands of organic compounds, which may have significant influence on the climate-relevant properties of atmospheric aerosols. An improved understanding of the molecular composition of AOM is needed to evaluate the effect of aerosol composition upon aerosol physical properties. Products of gas, aqueous and particle phase reactions contribute to the aerosol organic mass. Thus, ambient aerosols carry a complex array of AOM components with variable chemical signatures depending upon its origin and aerosol life-cycle processes. In this work, ultrahigh-resolution Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to characterize ambient aerosol AOM collected at the Storm Peak Laboratory (3210 m a.s.l.) near Steamboat Springs, CO. Thousands of molecular formulas were assigned in the mass range of m/z 100-800 after negative-ion electrospray ionization. Using multivariate statistical analysis, correlations between the site meteorological conditions and specific molecular compositions were identified. For example, days with strong UV radiation and high temperature were found to contain large numbers of biogenic SOA molecular formulas. Similarly, days with high relative humidity and high sulfate concentrations were found to contain many sulfur-containing compounds, suggesting their aqueous phase formation.

  14. Characterization of urban aerosol using aerosol mass spectrometry and proton nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Cleveland, M. J.; Ziemba, L. D.; Griffin, R. J.; Dibb, J. E.; Anderson, C. H.; Lefer, B.; Rappenglück, B.

    2012-07-01

    Particulate matter was measured during August and September of 2006 in Houston as part of the Texas Air Quality Study II Radical and Aerosol Measurement Project. Aerosol size and composition were determined using an Aerodyne quadrupole aerosol mass spectrometer. Aerosol was dominated by sulfate (4.1 ± 2.6 μg m-3) and organic material (5.5 ± 4.0 μg m-3), with contributions of organic material from both primary (˜32%) and secondary (˜68%) sources. Secondary organic aerosol appears to be formed locally. In addition, 29 aerosol filter samples were analyzed using proton nuclear magnetic resonance (1H NMR) spectroscopy to determine relative concentrations of organic functional groups. Houston aerosols are less oxidized than those observed elsewhere, with smaller relative contributions of carbon-oxygen double bonds. These particles do not fit 1H NMR source apportionment fingerprints for identification of secondary, marine, and biomass burning organic aerosol, suggesting that a new fingerprint for highly urbanized and industrially influenced locations be established.

  15. Organic Aerosols in Rural and Remote Atmospheric Environments: Insights from Aerosol Mass Spectrometry

    Science.gov (United States)

    Zhang, Q.; Jimenez, J.; Ulbrich, I.; Dunlea, E.; Decarlo, P.; Huffman, A.; Allan, J.; Coe, H.; Alfarra, R.; Canagaratna, M.; Onasch, T.; Jayne, J.; Worsnop, D.; Takami, A.; Miyoshi, T.; Shimono, A.; Hatakeyama, S.; Weimer, S.; Demerjian, K.; Drewnick, F.; Schneider, J.; Middlebrook, A.; Bahreini, R.; Cotrell, L.; Griffin, R.; Leaitch, R.; Li, S.; Hayden, K.; Rautiainen, J.

    2006-12-01

    Organic matter usually accounts for a large fraction of the fine particle mass in rural and remote atmospheres. However, little is known about the sources and properties of this material. Here we report findings on the characteristics and the major types of organic aerosols (OA) in urban downwind, high elevation, forested, and marine atmospheres based on analyses of more than 20 highly time resolved AMS datasets sampled from various locations in the mid-latitude Northern Hemisphere. Organic aerosol components are extracted from these datasets using a custom multiple component mass spectral analysis technique and the Positive Matrix Factorization (PMF) method. These components are evaluated according to their extracted mass spectra and correlations to aerosol species, such as sulfate, nitrate, and elemental carbon, and gas-phase tracer compounds, such as CO and NOx. We have identified a hydrocarbon-like organic aerosol (HOA) component similar in mass spectra to the hydrocarbon substances observed at urban locations. We have also identified several oxygenated OA (OOA) components that show different fragmentation patterns and oxygen to carbon ratios in their mass spectra. Two OOA components a highly oxygenated that has mass spectrum resembling that of fulvic acid (a model compound representative for highly processed/oxidized organics in the environment) and a less oxygenated OOA component, whose spectrum is dominated with ions that are mainly associated with carbonyls and alcohols, are very frequently observed at various rural/remote sites. The oxygenated OOA component is more prevalent at downwind sites influenced by urban transport and the less oxygenated shows correlation to biogenic chamber OA at some locations. Compared to the total OOA concentration, HOA is generally very small and accounts for high elevation site (the Whistler Mountain Summit, Canada) of North America. Finally, an attempt will be made to address the relative importance of secondary vs. primary

  16. Aerosol Organic Matter-Trace Metal Relationships Revealed by Ultra-High Resolution Mass Spectrometry

    Science.gov (United States)

    Wozniak, A. S.; Sleighter, R. L.; Morton, P. L.; Landing, W. M.; Shelley, R. U.; Hatcher, P. G.

    2011-12-01

    Atmospheric delivery of aerosols is important for the biogeochemical cycling of organic matter (OM) and trace elements in marine environments. Aerosols over marine environments can be derived from marine sources or transported from continental regions of variable vegetative cover and anthropogenic influence. These different sources are key determinants of aerosol OM composition, as well as trace metal amounts and characteristics. Dust-influenced aerosols typically contain higher amounts of Fe than anthropogenic-influenced aerosols but have lesser % of soluble Fe (%FeS), believed to be the bioavailable form of Fe for marine phytoplankton. Four samples from the 2008 GEOTRACES intercalibration experiments (Miami, FL, USA) were analyzed by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and related to both air mass back trajectories and %FeS. Three samples showed aerosol sources from the east consistent with Saharan dust inputs, while the fourth sample was derived in part from air masses to the north, influenced by the North American continent. This North American-influenced sample was collected following the 3 day period with the highest %FeS (1.3-1.7%) of the 11 day intercalibration experiment (mean = 0.4-1.1%). FT-ICR mass spectra showed 795 peaks common to the dust-influenced samples but absent from the North American-influenced sample. These peaks were assigned molecular formulas characterized by CHO and CHON compounds with lower H/C and O/C ratios than the 1257 formulas common to all 4 samples, suggesting that the dust-influenced aerosols carry OM that is less oxygenated and more condensed in structure along with Fe of lesser solubility. Air mass trajectory analyses revealed samples collected during a 2010 cruise in the North Atlantic Ocean to be characterized by European-influenced (anthropogenic), African-influenced (dust), and primarily marine air masses, making them ideal for further exploration of the

  17. Functional group composition of ambient and source organic aerosols determined by tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    J. Dron

    2010-04-01

    Full Text Available The functional group composition of various organic aerosols (OA is being investigated using a recently developed analytical approach based on atmospheric pressure chemical ionisation-tandem mass spectrometry (APCI-MS/MS. The determinations of the three functional groups' contents are performed quantitatively by neutral loss (carboxylic and carbonyl groups and precursor ion (nitro groups scanning modes of a tandem mass spectrometer. Major organic aerosol sources are studied: vehicular emission and wood combustion for primary aerosol sources; and a secondary organic aerosol (SOA produced through photo-oxidation of o-xylene. The results reveal significant differences in the functional group contents of these source aerosols. The laboratory generated SOA is dominated by carbonyls while carboxylics are preponderate in the wood combustion particles. On the other hand, vehicular emissions are characterised by a strong nitro content. The total amount of the three functional groups accounted for 1.7% (vehicular to 13.5% (o-xylene photo-oxidation of the organic carbon. The diagnostic functional group ratios are then used to tentatively differentiate sources of particles collected in an urban background environment located in an Alpine valley (Chamonix, France during a strong winter pollution event. The three functional groups under study account for a total functionalisation rate of 2.2 to 3.8% of the organic carbon in this ambient aerosol, which is also dominated by carboxylic moieties. In this particular case study of a deep alpine valley during winter, we show that the nitro- and carbonyl-to-carboxylic diagnostic ratios can be a useful tool to distinguish the sources. In these conditions, the total OA concentrations are highly dominated by wood combustion OA. This result is confirmed by an organic markers source apportionment approach which assesses a wood burning organic carbon contribution of about 60%. Finally, examples of functional group mass

  18. Chemical composition and characteristics of ambient aerosols and rainwater residues during Indian summer monsoon: Insight from aerosol mass spectrometry

    Science.gov (United States)

    Chakraborty, Abhishek; Gupta, Tarun; Tripathi, Sachchida N.

    2016-07-01

    Real time composition of non-refractory submicron aerosol (NR-PM1) is measured via Aerosol mass spectrometer (AMS) for the first time during Indian summer monsoon at Kanpur, a polluted urban location located at the heart of Indo Gangetic Plain (IGP). Submicron aerosols are found to be dominated by organics followed by nitrate. Source apportionment of organic aerosols (OA) via positive matrix factorization (PMF) revealed several types of secondary/oxidized and primary organic aerosols. On average, OA are completely dominated by oxidized OA with a very little contribution from biomass burning OA. During rain events, PM1 concentration is decreased almost by 60%, but its composition remains nearly the same. Oxidized OA showed slightly more decrease than primary OAs, probably due to their higher hygroscopicity. The presence of organo nitrates (ON) is also detected in ambient aerosols. Apart from real-time sampling, collected fog and rainwater samples were also analyzed via AMS in offline mode and in the ICP-OES (Inductively coupled plasma - Optical emission spectrometry) for elements. The presence of sea salt, organo nitrates and sulfates has been observed. Rainwater residues are also dominated by organics but their O/C ratios are 15-20% lower than the observed values for ambient OA. Alkali metals such as Ca, Na, K are found to be most abundant in the rainwater followed by Zn. Rainwater residues are also found to be much less oxidized than the aerosols present inside the fog water, indicating presence of less oxidized organics. These findings indicate that rain can act as an effective scavenger of different types of pollutants even for submicron particle range. Rainwater residues also contain organo sulfates which indicate that some portion of the dissolved aerosols has undergone aqueous processing, possibly inside the cloud. Highly oxidized and possibly hygroscopic OA during monsoon period compared to other seasons (winter, post monsoon), indicates that they can act

  19. Detection of biological particles in ambient air using Bio-Aerosol Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    McJimpsey, E L; Steele, P T; Coffee, K R; Fergenson, D P; Riot, V J; Woods, B W; Gard, E E; Frank, M; Tobias, H J; Lebrilla, C

    2006-03-16

    The Bio-Aerosol Mass Spectrometry (BAMS) system is an instrument used for the real time detection and identification of biological aerosols. Particles are drawn from the atmosphere directly into vacuum and tracked as they scatter light from several continuous wave lasers. After tracking, the fluorescence of individual particles is excited by a pulsed 266nm or 355nm laser. Molecules from those particles with appropriate fluorescence properties are subsequently desorbed and ionized using a pulsed 266nm laser. Resulting ions are analyzed in a dual polarity mass spectrometer. During two field deployments at the San Francisco International Airport, millions of ambient particles were analyzed and a small but significant fraction were found to have fluorescent properties similar to Bacillus spores and vegetative cells. Further separation of non-biological background particles from potential biological particles was accomplished using laser desorption/ionization mass spectrometry. This has been shown to enable some level of species differentiation in specific cases, but the creation and observation of higher mass ions is needed to enable a higher level of specificity across more species. A soft ionization technique, matrix-assisted laser desorption/ionization (MALDI) is being investigated for this purpose. MALDI is particularly well suited for mass analysis of biomolecules since it allows for the generation of molecular ions from large mass compounds that would fragment under normal irradiation. Some of the initial results from a modified BAMS system utilizing this technique are described.

  20. Ion mobility spectrometry-mass spectrometry (IMS-MS) for on- and offline analysis of atmospheric gas and aerosol species

    Science.gov (United States)

    Krechmer, Jordan E.; Groessl, Michael; Zhang, Xuan; Junninen, Heikki; Massoli, Paola; Lambe, Andrew T.; Kimmel, Joel R.; Cubison, Michael J.; Graf, Stephan; Lin, Ying-Hsuan; Budisulistiorini, Sri H.; Zhang, Haofei; Surratt, Jason D.; Knochenmuss, Richard; Jayne, John T.; Worsnop, Douglas R.; Jimenez, Jose-Luis; Canagaratna, Manjula R.

    2016-07-01

    Measurement techniques that provide molecular-level information are needed to elucidate the multiphase processes that produce secondary organic aerosol (SOA) species in the atmosphere. Here we demonstrate the application of ion mobility spectrometry-mass spectrometry (IMS-MS) to the simultaneous characterization of the elemental composition and molecular structures of organic species in the gas and particulate phases. Molecular ions of gas-phase organic species are measured online with IMS-MS after ionization with a custom-built nitrate chemical ionization (CI) source. This CI-IMS-MS technique is used to obtain time-resolved measurements (5 min) of highly oxidized organic molecules during the 2013 Southern Oxidant and Aerosol Study (SOAS) ambient field campaign in the forested SE US. The ambient IMS-MS signals are consistent with laboratory IMS-MS spectra obtained from single-component carboxylic acids and multicomponent mixtures of isoprene and monoterpene oxidation products. Mass-mobility correlations in the 2-D IMS-MS space provide a means of identifying ions with similar molecular structures within complex mass spectra and are used to separate and identify monoterpene oxidation products in the ambient data that are produced from different chemical pathways. Water-soluble organic carbon (WSOC) constituents of fine aerosol particles that are not resolvable with standard analytical separation methods, such as liquid chromatography (LC), are shown to be separable with IMS-MS coupled to an electrospray ionization (ESI) source. The capability to use ion mobility to differentiate between isomers is demonstrated for organosulfates derived from the reactive uptake of isomers of isoprene epoxydiols (IEPOX) onto wet acidic sulfate aerosol. Controlled fragmentation of precursor ions by collisionally induced dissociation (CID) in the transfer region between the IMS and the MS is used to validate MS peak assignments, elucidate structures of oligomers, and confirm the

  1. Molecular composition of atmospheric aerosols from Halley Bay, Antarctica, using ultra-high resolution mass spectrometry

    Science.gov (United States)

    Kourtchev, Ivan; Brough, Neil; Rincon, Angela; Jones, Anna; Kalberer, Markus

    2016-04-01

    Antarctica is one of the few pristine places to study natural processes of atmospheric aerosols and anthropogenic impacts on the clean remote atmosphere. Although stratospheric aerosol in Antarctica has now been explored in some detail because of the ozone depletion phenomenon, tropospheric aerosol particles in Antarctica remain very little studied. The main goal of this work is to identify in detail the organic chemical composition of aerosol from Halley Bay station, which is located on the Brunt Ice Shelf floating on the Weddell Sea in Antarctica. In this study we characterise the molecular composition of aerosols from three seasons (summer, autumn and winter in 2012) using ultra-high resolution mass spectrometry (UHRMS). The technique provides high accuracy and high mass resolving power that allows determining unambiguous number of organic compounds present in complex organic mixtures (Noziere et al., 2015). The molecular composition interpretation was facilitated using visualisation methods (e.g. double bond equivalent, Van Krevelen diagrams, Kendrick mass analysis, and carbon oxidation state), which allowed to identify patterns, such as differences between sampling times and atmospheric processes. The majority of the identified compounds were attributed to nitrogen and sulphur containing species which exhibited very strong seasonal trends. Relatively large fraction (up to 30% of the total number of molecules) of these species contained very low hydrogen to carbon ratios (below 1) indicating that the site is impacted by anthropogenic emissions. Influences of the meteorological parameters and air mass trajectories on the molecular composition are discussed. Nozière et al., The Molecular Identification of Organic Compounds in the Atmosphere: State of the Art and Challenges, Chem. Rev., 115, 3920-3983, 2015.

  2. Molecular Chemistry of Organic Aerosols Through the Application of High Resolution Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Nizkorodov, Serguei; Laskin, Julia; Laskin, Alexander

    2011-01-05

    Understanding of molecular composition and fundamental chemical transformations of organic aerosols (OA) during their formation and aging is both a major challenge and the area of greatest uncertainty in atmospheric research. Particularly little is known about fundamental relationship between the chemical composition and physicochemical properties of OA, their atmospheric history, evolution, and impact on the environment. Ambient soft-ionization methods combined with high-resolution mass spectrometry (HR-MS) analysis provide detailed information on the molecular content of OA that is pivotal for improved understanding of their complex composition, multi-phase aging chemistry, direct (light absorption and scattering) and indirect (aerosol-cloud interactions) effects on atmospheric radiation and climate, and health effects. The HR-MS methods can detect thousands of individual OA constituents at once, provide their elemental formulae from accurate mass measurements, and provide structural information based on tandem mass spectrometry. Integration with additional analytical tools, such as chromatography and UV/Vis absorption spectroscopy, makes it possible to further separate OA compounds by their polarity and ability to absorb solar radiation. The goal of this perspective is to describe modern HR-MS methods, review recent applications to field and laboratory studies of OA, and explain how the information obtained from HR-MS methods can be translated into improved understanding of OA chemistry.

  3. Characterizing aerosol transport into the Canadian High Arctic using aerosol mass spectrometry and Lagrangian modelling

    Directory of Open Access Journals (Sweden)

    T. Kuhn

    2010-05-01

    Full Text Available We report the analysis of measurements made using an aerosol mass spectrometer (AMS; Aerodyne Research Inc. that was installed in the Polar Environment Atmospheric Research Laboratory (PEARL in summer 2006. PEARL is located in the Canadian high Arctic at 610 m above sea level on Ellesmere Island (80° N 86° W. PEARL is unique for its remote location in the Arctic and because most of the time it is situated within the free troposphere. It is therefore well suited as a receptor site to study the long range tropospheric transport of pollutants into the Arctic. Some information about the successful year-round operation of an AMS at a high Arctic site such as PEARL will be reported here, together with design considerations for reliable sampling under harsh low-temperature conditions. Computational fluid dynamics calculations were made to ensure that sample integrity was maintained while sampling air at temperatures that average −40 °C in the winter and can be as low as −55 °C. Selected AMS measurements of aerosol mass concentration, size, and chemical composition recorded during the months of August, September and October 2006 will be reported. During this period, sulfate was at most times the predominant aerosol component with on average 0.115 μg m−3 (detection limit 0.003 μg m−3. The second most abundant component was undifferentiated organic aerosol, with on average 0.11 μg m−3 detection limit (0.04 μg m−3. The nitrate component, which averaged 0.007 μg m−3, was above its detection limit (0.002 μg m−3, whereas the ammonium ion had an apparent average concentration of 0.02 μg m−3, which was approximately equal to its detection limit. A few episodes having increased mass concentrations and lasting from several hours to several days are apparent in the data. These were investigated further using a statistical analysis to determine their common

  4. Characterising aerosol transport into the Canadian High Arctic using aerosol mass spectrometry and Lagrangian modelling

    Directory of Open Access Journals (Sweden)

    T. Kuhn

    2010-11-01

    Full Text Available We report the analysis of measurements made using an aerosol mass spectrometer (AMS; Aerodyne Research Inc. that was installed in the Polar Environment Atmospheric Research Laboratory (PEARL in summer 2006. PEARL is located in the Canadian high Arctic at 610 m above sea level on Ellesmere Island (80° N 86° W. PEARL is unique for its remote location in the Arctic and because most of the time it is situated within the free troposphere. It is, therefore, well suited as a receptor site to study the long-range tropospheric transport of pollutants into the Arctic. Some information about the successful year-round operation of an AMS at a high Arctic site such as PEARL will be reported here, together with design considerations for reliable sampling under harsh low-temperature conditions. Computational fluid dynamics calculations were made to ensure that sample integrity was maintained while sampling air at temperatures that average −40 °C in the winter and can be as low as −55 °C. Selected AMS measurements of aerosol mass concentration, size and chemical composition recorded during the months of August, September and October 2006 will be reported. The air temperature was raised to about 20 °C during sampling, but the short residence time in the inlet system (~25 s ensured that less than 10% of semivolatiles such as ammonium nitrate were lost. During this period, sulfate was, at most times, the predominant aerosol component with on average 0.115 μg m−3 (detection limit 0.003 μg m−3. The second most abundant component was undifferentiated organic aerosol, with on average 0.11 μg m−3 (detection limit 0.04 μg m−3. The nitrate component, which averaged 0.007 μg m−3, was above its detection limit (0.002 μg m−3, whereas the ammonium ion had an apparent average concentration of 0.02 μg m−3, which was approximately equal to its detection limit. A few

  5. Organic aerosol components observed in Northern Hemispheric datasets from Aerosol Mass Spectrometry

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    N. L. Ng

    2010-05-01

    Full Text Available In this study we compile and present results from the factor analysis of 43 Aerosol Mass Spectrometer (AMS datasets (27 of the datasets are reanalyzed in this work. The components from all sites, when taken together, provide a holistic overview of Northern Hemisphere organic aerosol (OA and its evolution in the atmosphere. At most sites, the OA can be separated into oxygenated OA (OOA, hydrocarbon-like OA (HOA, and sometimes other components such as biomass burning OA (BBOA. We focus on the OOA components in this work. In many analyses, the OOA can be further deconvolved into low-volatility OOA (LV-OOA and semi-volatile OOA (SV-OOA. Differences in the mass spectra of these components are characterized in terms of the two main ions m/z 44 (CO2+ and m/z 43 (mostly C2H3O+, which are used to develop a new mass spectral diagnostic for following the aging of OA components in the atmosphere. The LV-OOA component spectra have higher f44 (ratio of m/z 44 to total signal in the component mass spectrum and lower f43 (ratio of m/z 43 to total signal in the component mass spectrum than SV-OOA. A wide range of f44 and O:C ratios are observed for both LV-OOA (0.17±0.04, 0.73±0.14 and SV-OOA (0.07±0.04, 0.35±0.14 components, reflecting the fact that there is a continuum of OOA properties in ambient aerosol. The OOA components (OOA, LV-OOA, and SV-OOA from all sites cluster within a well-defined triangular region in the f44 vs. f43 space, which can be used as a standardized means for comparing and characterizing any OOA components (laboratory or ambient observed with the AMS. Examination of the OOA components in this triangular space indicates that OOA component spectra become increasingly similar to each other and to fulvic acid and HULIS sample spectra as f44 (a

  6. Ultrasensitive detection of inhaled organic aerosol particles by accelerator mass spectrometry.

    Science.gov (United States)

    Parkhomchuk, E V; Gulevich, D G; Taratayko, A I; Baklanov, A M; Selivanova, A V; Trubitsyna, T A; Voronova, I V; Kalinkin, P N; Okunev, A G; Rastigeev, S A; Reznikov, V A; Semeykina, V S; Sashkina, K A; Parkhomchuk, V V

    2016-09-01

    Accelerator mass spectrometry (AMS) was shown to be applicable for studying the penetration of organic aerosols, inhaled by laboratory mice at ultra-low concentration ca. 10(3) cm(-3). We synthesized polystyrene (PS) beads, composed of radiocarbon-labeled styrene, for testing them as model organic aerosols. As a source of radiocarbon we used methyl alcohol with radioactivity. Radiolabeled polystyrene beads were obtained by emulsifier-free emulsion polymerization of synthesized (14)C-styrene initiated by K2S2O8 in aqueous media. Aerosol particles were produced by pneumatic spraying of diluted (14)C-PS latex. Mice inhaled (14)C-PS aerosol consisting of the mix of 10(3) 225-nm particles per 1 cm(3) and 5·10(3) 25-nm particles per 1 cm(3) for 30 min every day during five days. Several millions of 225-nm particles deposited in the lungs and slowly excreted from them during two weeks of postexposure. Penetration of particles matter was also observed for liver, kidneys and brain, but not for a heart. PMID:27281540

  7. Urban increments of gaseous and aerosol pollutants and their sources using mobile aerosol mass spectrometry measurements

    Science.gov (United States)

    Elser, Miriam; Bozzetti, Carlo; El-Haddad, Imad; Maasikmets, Marek; Teinemaa, Erik; Richter, Rene; Wolf, Robert; Slowik, Jay G.; Baltensperger, Urs; Prévôt, André S. H.

    2016-06-01

    Air pollution is one of the main environmental concerns in urban areas, where anthropogenic emissions strongly affect air quality. This work presents the first spatially resolved detailed characterization of PM2.5 (particulate matter with aerodynamic equivalent diameter daero ≤ 2.5 µm) in two major Estonian cities, Tallinn and Tartu. The measurements were performed in March 2014 using a mobile platform. In both cities, the non-refractory (NR)-PM2.5 was characterized by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) using a recently developed lens which increases the transmission of super-micron particles. Equivalent black carbon (eBC) and several trace gases including carbon monoxide (CO), carbon dioxide (CO2), and methane (CH4) were also measured. The chemical composition of PM2.5 was found to be very similar in the two cities. Organic aerosol (OA) constituted the largest fraction, explaining on average about 52 to 60 % of the PM2.5 mass. Four sources of OA were identified using positive matrix factorization (PMF): hydrocarbon-like OA (HOA, from traffic emissions), biomass burning OA (BBOA, from biomass combustion), residential influenced OA (RIOA, probably mostly from cooking processes with possible contributions from waste and coal burning), and oxygenated OA (OOA, related to secondary aerosol formation). OOA was the major OA source during nighttime, explaining on average half of the OA mass, while during daytime mobile measurements the OA was affected by point sources and dominated by the primary fraction. A strong increase in the secondary organic and inorganic components was observed during periods with transport of air masses from northern Germany, while the primary local emissions accumulated during periods with temperature inversions. Mobile measurements offered the identification of different source regions within the urban areas and the assessment of the extent to which pollutants concentrations exceeded regional background

  8. Functional group composition of ambient and source organic aerosols determined by tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dron, J.; El Haddad, I.; Temime-Roussel, B.; Wortham, H.; Marchand, N. [Univ Aix Marseille, CNRS, Lab Chim Provence, Equipe Instrumentat and React Atmospher, UMR 6264, F-13331 Marseille 3 (France); Jaffrezo, J.L. [Univ Grenoble 1, CNRS, UMR 5183, Lab Glaciol and Geophys Environm, F-38402 St Martin Dheres (France)

    2010-07-01

    The functional group composition of various organic aerosols (OA) is investigated using a recently developed analytical approach based on atmospheric pressure chemical ionisation-tandem mass spectrometry (APCIMS/MS). The determinations of three functional groups contents are performed quantitatively by neutral loss (carboxylic and carbonyl groups, R-COOH and R-CO-R' respectively) and precursor ion (nitro groups, R-NO{sub 2}) scanning modes of a tandem mass spectrometer. Major organic aerosol sources are studied: vehicular emission and wood combustion for primary aerosol sources; and a secondary organic aerosol (SOA) produced through photooxidation of o-xylene. The results reveal significant differences in the functional group contents of these source aerosols. The laboratory generated SOA is dominated by carbonyls while carboxylics are preponderate in the wood combustion particles. On the other hand, vehicular emissions are characterised by a strong nitro content. The total amount of the three functional groups accounts for 1.7% (vehicular) to 13.5% (o-xylene photooxidation) of the organic carbon. Diagnostic functional group ratios are then used to tentatively discriminate sources of particles collected in an urban background environment located in an Alpine valley (Chamonix, France) during a strong winter pollution event. The three functional groups under study account for a total functionalization rate of 2.2 to 3.8% of the organic carbon in this ambient aerosol, which is also dominated by carboxylic moieties. In this particular case study of a deep alpine valley during winter, we show that the nitro- and carbonyl-to-carboxylic diagnostic ratios can be a useful tool to discriminate sources. In these conditions, the total OA concentrations are highly dominated by wood combustion OA. This result is confirmed by an organic markers source apportionment approach which assess a wood burning organic carbon contribution of about 60%. Finally, examples of functional

  9. Functional group composition of ambient and source organic aerosols determined by tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    J. Dron

    2010-08-01

    Full Text Available The functional group composition of various organic aerosols (OA is investigated using a recently developed analytical approach based on atmospheric pressure chemical ionisation-tandem mass spectrometry (APCI-MS/MS. The determinations of three functional groups contents are performed quantitatively by neutral loss (carboxylic and carbonyl groups, R-COOH and R-CO-R´ respectively and precursor ion (nitro groups, R-NO2 scanning modes of a tandem mass spectrometer. Major organic aerosol sources are studied: vehicular emission and wood combustion for primary aerosol sources; and a secondary organic aerosol (SOA produced through photooxidation of o-xylene. The results reveal significant differences in the functional group contents of these source aerosols. The laboratory generated SOA is dominated by carbonyls while carboxylics are preponderate in the wood combustion particles. On the other hand, vehicular emissions are characterised by a strong nitro content. The total amount of the three functional groups accounts for 1.7% (vehicular to 13.5% (o-xylene photooxidation of the organic carbon. Diagnostic functional group ratios are then used to tentatively discriminate sources of particles collected in an urban background environment located in an Alpine valley (Chamonix, France during a strong winter pollution event. The three functional groups under study account for a total functionalisation rate of 2.2 to 3.8% of the organic carbon in this ambient aerosol, which is also dominated by carboxylic moieties. In this particular case study of a deep alpine valley during winter, we show that the nitro- and carbonyl-to-carboxylic diagnostic ratios can be a useful tool to discriminate sources. In these conditions, the total OA concentrations are highly dominated by wood combustion OA. This result is confirmed by an organic markers source apportionment approach which assess a wood burning organic carbon contribution of about 60

  10. Functional group composition of ambient and source organic aerosols determined by tandem mass spectrometry

    International Nuclear Information System (INIS)

    The functional group composition of various organic aerosols (OA) is investigated using a recently developed analytical approach based on atmospheric pressure chemical ionisation-tandem mass spectrometry (APCIMS/MS). The determinations of three functional groups contents are performed quantitatively by neutral loss (carboxylic and carbonyl groups, R-COOH and R-CO-R' respectively) and precursor ion (nitro groups, R-NO2) scanning modes of a tandem mass spectrometer. Major organic aerosol sources are studied: vehicular emission and wood combustion for primary aerosol sources; and a secondary organic aerosol (SOA) produced through photooxidation of o-xylene. The results reveal significant differences in the functional group contents of these source aerosols. The laboratory generated SOA is dominated by carbonyls while carboxylics are preponderate in the wood combustion particles. On the other hand, vehicular emissions are characterised by a strong nitro content. The total amount of the three functional groups accounts for 1.7% (vehicular) to 13.5% (o-xylene photooxidation) of the organic carbon. Diagnostic functional group ratios are then used to tentatively discriminate sources of particles collected in an urban background environment located in an Alpine valley (Chamonix, France) during a strong winter pollution event. The three functional groups under study account for a total functionalization rate of 2.2 to 3.8% of the organic carbon in this ambient aerosol, which is also dominated by carboxylic moieties. In this particular case study of a deep alpine valley during winter, we show that the nitro- and carbonyl-to-carboxylic diagnostic ratios can be a useful tool to discriminate sources. In these conditions, the total OA concentrations are highly dominated by wood combustion OA. This result is confirmed by an organic markers source apportionment approach which assess a wood burning organic carbon contribution of about 60%. Finally, examples of functional group mass

  11. Detection of brake wear aerosols by aerosol time-of-flight mass spectrometry

    Science.gov (United States)

    Beddows, D. C. S.; Dall'Osto, M.; Olatunbosun, O. A.; Harrison, Roy M.

    2016-03-01

    Brake dust particles were characterised using an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) operated using two inlet configurations, namely the aerodynamic lens (AFL) inlet and countersunk nozzle inlet. Laboratory studies show that dust particles are characterised by mass spectra containing ions deriving from Fe and Ba and although highly correlated to each other, the Fe and Ba signals were mostly detected using the nozzle inlet with relatively high laser desorption energies. When using the AFL, only [56Fe] and [-88FeO2] ions were observed in brake dust spectra generated using lower laser desorption pulse energies, and only above 0.75 mJ was the [138Ba] ion detected. When used with the preferred nozzle inlet configuration, the [-88FeO2] peak was considered to be the more reliable tracer peak, because it is not present in other types of dust (mineral, tyre, Saharan etc). As shown by the comparison with ambient data from a number of locations, the aerodynamic lens is not as efficient in detecting brake wear particles, with less than 1% of sampled particles attributed to brake wear. Five field campaigns within Birmingham (background, roadside (3) and road tunnel) used the nozzle inlet and showed that dust particles (crustal and road) accounted for between 3.1 and 65.9% of the particles detected, with the remaining particles being made up from varying percentages of other constituents.

  12. Seasonal differences of urban organic aerosol composition - an ultra-high resolution mass spectrometry study

    Science.gov (United States)

    Rincon, A. G.; Calvo, A. I.; Dietzel, M.; Kalberer, M.

    2012-04-01

    The understanding of the chemical composition of atmospheric aerosols, their properties and reactivity are important for assessing aerosol effects upon both global climate change and human health. The composition of organic aerosols is poorly understood mainly due to their highly complex chemical composition with several thousand compounds. In the present study the water-soluble organic fraction of ambient particles collected at an urban site in Cambridge, UK, during different seasons were analysed with ultra-high resolution mass spectrometry. For several thousand peaks in the mass specta (between 3000-6000) an elemental composition could be assigned and summer samples generally contained more components than winter samples. Up to 80% of the peaks in the mass spectra contain nitrogen and/or sulphur functional groups and only about 20% of the compounds contain only C, H and O atoms. In summer the fraction of compounds with oxidized nitrogen and sulphur groups increases compared to winter indicating a photo-chemical formation route of these multifunctional compounds. In addition to oxidized nitrogen compounds a large number of highly unsaturated reduced nitrogen-containing compounds were detected, corresponding likely to cyclic amines. A significant number of oxidized PAHs have been detected in summer samples, which were not present in winter, indicating again photo-chemical aging processes. Both, amines and long-chain aliphatic acids (also frequently observed in these urban samples) are likely signatures of biomass burning and primary biological sources. Potential biomass burning markers are discussed. Particle-phase oligomerisation reactions have only been observed to a very limited degree. Compounds larger than m/z 350 almost exclusively contained N and/or S functional groups indicating that the high molecular weight compounds in these organic aerosol extracts might be mainly due to particle-phase heterogeneous reactions of organic compounds with inorganic

  13. Mass spectrometry.

    Science.gov (United States)

    Burlingame, A. L.; Johanson, G. A.

    1972-01-01

    Review of the current state of mass spectrometry, indicating its unique importance for advanced scientific research. Mass spectrometry applications in computer techniques, gas chromatography, ion cyclotron resonance, molecular fragmentation and ionization, and isotope labeling are covered. Details are given on mass spectrometry applications in bio-organic chemistry and biomedical research. As the subjects of these applications are indicated alkaloids, carbohydrates, lipids, terpenes, quinones, nucleic acid components, peptides, antibiotics, and human and animal metabolisms. Particular attention is given to the mass spectra of organo-inorganic compounds, inorganic mass spectrometry, surface phenomena such as secondary ion and electron emission, and elemental and isotope analysis. Further topics include mass spectrometry in organic geochemistry, applications in geochronology and cosmochemistry, and organic mass spectrometry.

  14. Molecular composition of organic aerosols in central Amazonia: an ultra-high-resolution mass spectrometry study

    Science.gov (United States)

    Kourtchev, Ivan; Godoi, Ricardo H. M.; Connors, Sarah; Levine, James G.; Archibald, Alex T.; Godoi, Ana F. L.; Paralovo, Sarah L.; Barbosa, Cybelli G. G.; Souza, Rodrigo A. F.; Manzi, Antonio O.; Seco, Roger; Sjostedt, Steve; Park, Jeong-Hoo; Guenther, Alex; Kim, Saewung; Smith, James; Martin, Scot T.; Kalberer, Markus

    2016-09-01

    The Amazon Basin plays key role in atmospheric chemistry, biodiversity and climate change. In this study we applied nanoelectrospray (nanoESI) ultra-high-resolution mass spectrometry (UHRMS) for the analysis of the organic fraction of PM2.5 aerosol samples collected during dry and wet seasons at a site in central Amazonia receiving background air masses, biomass burning and urban pollution. Comprehensive mass spectral data evaluation methods (e.g. Kendrick mass defect, Van Krevelen diagrams, carbon oxidation state and aromaticity equivalent) were used to identify compound classes and mass distributions of the detected species. Nitrogen- and/or sulfur-containing organic species contributed up to 60 % of the total identified number of formulae. A large number of molecular formulae in organic aerosol (OA) were attributed to later-generation nitrogen- and sulfur-containing oxidation products, suggesting that OA composition is affected by biomass burning and other, potentially anthropogenic, sources. Isoprene-derived organosulfate (IEPOX-OS) was found to be the most dominant ion in most of the analysed samples and strongly followed the concentration trends of the gas-phase anthropogenic tracers confirming its mixed anthropogenic-biogenic origin. The presence of oxidised aromatic and nitro-aromatic compounds in the samples suggested a strong influence from biomass burning especially during the dry period. Aerosol samples from the dry period and under enhanced biomass burning conditions contained a large number of molecules with high carbon oxidation state and an increased number of aromatic compounds compared to that from the wet period. The results of this work demonstrate that the studied site is influenced not only by biogenic emissions from the forest but also by biomass burning and potentially other anthropogenic emissions from the neighbouring urban environments.

  15. Time-of-flight aerosol mass spectrometry: Measuring gaseous iodine species after selective uptake in lab-generated aerosols

    Science.gov (United States)

    Kundel, Michael; Ries, Marco; Schott, Mathias; Hoffmann, Thorsten

    2010-05-01

    Reactive iodine species play an important role in the marine atmospheric chemistry. Recent studies show that iodine containing compounds (e.g. I2 and ICl) are involved in the tropospheric ozone depletion, the enrichment of iodine in marine aerosols and the formation of new particles in the marine boundary layer (MBL). Various laboratory and field measurements report that molecular iodine (I2) and organoiodine compounds (e.g. CH3I, CH2I2) are the most important precursors for reactive iodine in the MBL[1],[2]. However, the identification and quantification of reactive iodine containing compounds are still analytical challenges. Here, we present a new application of the time-of-flight aerosol mass spectrometer (ToF-AMS) for the quantification of gaseous I2 and ICl in real-time. Time-of-flight aerosol mass spectrometry enables the real-time analysis of the particle size, the particle mass and the chemical composition of non-refractory aerosols[3]. The aerosol enters the ToF-AMS through a critical orifice of 100 μm inner diameter. An aerodynamic lens system focuses the particles in a size range of 50-600 nm as a narrow beam into the vacuum system. While most of the air is removed by a skimmer, the particle beam is transmitted into the particle-sizing chamber. After passing the particle-sizing chamber, the non-refractory particles are flash-vaporized on a heated tungsten surface (500-600 °C) and then ionized by electron impact. The generated ions are extracted by an orthogonal extractor into the time-of-flight mass spectrometer, where the time resolved particle mass detection is performed. Since gaseous compounds are removed inside the ToF-AMS, a direct measurement of gaseous iodine species is not possible. Therefore gaseous iodine species have to be transferred from the gas phase to the particle phase before entering the ToF-AMS. For this purpose α-cyclodextrin (α-CD) particles were used as selective sampling probes for I2 and 1,3,5-trimethoxybenzene (1,3,5-TMB

  16. Measurement of ambient aerosols in northern Mexico City by single particle mass spectrometry

    Directory of Open Access Journals (Sweden)

    R. C. Moffet

    2007-05-01

    Full Text Available Continuous ambient measurements with aerosol time-of-flight mass spectrometry (ATOFMS were carried out in an industrial/residential section in the northern part of Mexico City as part of the Mexico City Metropolitan Area – 2006 campaign (MCMA-2006 between 7–27 March, 2006. Biomass and organic carbon (OC particle types were found to dominate the accumulation mode both day and night. The concentrations of both organic carbon and biomass particles were roughly equal early in the morning, but biomass became the largest contributor to the accumulation mode mass from the late morning until early evening. The diurnal pattern can be attributed to aging and/or a change in meteorology. Fresh elemental carbon (EC particles were observed during rush hour. The majority of the EC particles were mixed with nitrate, sulfate, organic carbon and potassium. Submicron particles from industrial sources in the northeast were composed of an internal mixture of Pb, Zn, EC and Cl and peaked early in the morning. A unique nitrogen-containing organic (NOC particle type was observed, and is hypothesized to be from industrial emissions based on the temporal profile and back trajectory analysis. This study provides unique insights into the real-time changes in single particle mixing state as a function of size and time for aerosols in Mexico City. These new findings indicate that biomass burning and industrial operations make significant contributions to particles in Mexico City. These sources have received relatively little attention in previous intensive field campaigns.

  17. Determination of particulate lead during MILAGRO / MCMA-2006 using Aerosol Mass Spectrometry

    Science.gov (United States)

    Salcedo, Dara; Onasch, T. B.; Aiken, A. C.; Williams, L. R.; de Foy, B.; Cubison, M. J.; Worsnop, D. R.; Molina, L. T.; Jimenez, J. L.

    2010-05-01

    We report the first measurements of particulate lead (Pb) from Aerodyne Aerosol Mass Spectrometers, which were deployed in and around Mexico City during the Megacity Initiative: Local and Global Research Observations (MILAGRO) / Mexico City Metropolitan Area 2006 (MCMA-2006) field campaigns. The high resolution mass spectrometer of one of the AMS instruments (HR-AMS) and the measured isotopic ratios unequivocally prove the detection of Pb in ambient particles. A substantial fraction of the lead evaporated slowly from the vaporizer of the instruments, which is indicative of species with low volatility at 600oC. A model was developed in order to estimate the ambient particulate Pb entering the AMS from the signals in the "open" and the "closed" (or "background") mass spectrum modes of the AMS. The model suggests the presence of at least two lead fractions with ~25% of the Pb signal exhibiting rapid evaporation (1/e decay constant, τ PEMEX32 site). From laboratory experiments with pure Pb(NO3)2 particles, we estimated that the Pb ionization efficiency relative to nitrate (RIEPb) is 0.5. Comparison of time series of AMS Pb with other measurements carried out at the T0 urban supersite during MILAGRO (using Proton Induced X-ray Emission (PIXE), Inductively-Coupled Plasma Mass Spectrometry (ICP-MS) and single-particle counts from an Aerosol Time-of-Fight Mass Spectrometer (ATOFMS)) shows similar levels (for PIXE and ICP-MS) and substantial correlation. During part of the campaign, sampling at T0 was alternated every 10 minutes with an Aerosol Concentrator, which enabled the detection of signals for PbCl+ and PbS+ ions. PbS+ displays the signature of a slowly evaporating species, while PbCl+ appears to arise only from fast evaporation, which is likely due to the higher vapor pressure of the compounds generating PbCl+. This is consistent with the evaporation model results. Levels of particulate Pb measured during MILAGRO at T0 were similar to previous studies in Mexico

  18. Determination of particulate lead using aerosol mass spectrometry: MILAGRO/MCMA-2006 observations

    Science.gov (United States)

    Salcedo, D.; Onasch, T. B.; Aiken, A. C.; Williams, L. R.; de Foy, B.; Cubison, M. J.; Worsnop, D. R.; Molina, L. T.; Jimenez, J. L.

    2010-06-01

    We report the first measurements of particulate lead (Pb) from Aerodyne Aerosol Mass Spectrometers, which were deployed in and around Mexico City during the Megacity Initiative: Local and Global Research Observations (MILAGRO)/Mexico City Metropolitan Area 2006 (MCMA-2006) field campaigns. The high resolution mass spectrometer of one of the AMS instruments (HR-AMS) and the measured isotopic ratios unequivocally prove the detection of Pb in ambient particles. A substantial fraction of the lead evaporated slowly from the vaporizer of the instruments, which is indicative of species with low volatility at 600 °C. A model was developed in order to estimate the ambient particulate Pb entering the AMS from the signals in the "open" and the "closed" (or "background") mass spectrum modes of the AMS. The model suggests the presence of at least two lead fractions with ~25% of the Pb signal exhibiting rapid evaporation (1/e decay constant, τPEMEX site). From laboratory experiments with pure Pb(NO3)2 particles, we estimated that the Pb ionization efficiency relative to nitrate (RIEPb) is 0.5. Comparison of time series of AMS Pb with other measurements carried out at the T0 supersite during MILAGRO (using Proton Induced X-ray Emission (PIXE), Inductively-Coupled Plasma Mass Spectrometry (ICP-MS) and single-particle counts from an Aerosol Time-of-Fight Mass Spectrometer (ATOFMS)) shows similar levels (for PIXE and ICP-MS) and substantial correlation. During part of the campaign, sampling at T0 was alternated every 10 min with an Aerosol Concentrator, which enabled the detection of signals for PbCl+ and PbS+ ions. PbS+ displays the signature of a slowly evaporating species, while PbCl+ appears to arise only from fast evaporation, which is likely due to the higher vapor pressure of the compounds generating PbCl+. This is consistent with the evaporation model results. Levels of particulate Pb measured at T0 were similar to previous studies in Mexico City. Pb shows a diurnal cycle

  19. Characterization of ice-nucleating bacteria using on-line electron impact ionization aerosol mass spectrometry.

    Science.gov (United States)

    Wolf, R; Slowik, J G; Schaupp, C; Amato, P; Saathoff, H; Möhler, O; Prévôt, A S H; Baltensperger, U

    2015-04-01

    The mass spectral signatures of airborne bacteria were measured and analyzed in cloud simulation experiments at the AIDA (Aerosol Interaction and Dynamics in the Atmosphere) facility. Suspensions of cultured cells in pure water were sprayed into the aerosol and cloud chambers forming an aerosol which consisted of intact cells, cell fragments and residual particles from the agar medium in which the bacteria were cultured. The aerosol particles were analyzed with a high-resolution time-of-flight aerosol mass spectrometer equipped with a newly developed PM2.5 aerodynamic lens. Positive matrix factorization (PMF) using the multilinear engine (ME-2) source apportionment was applied to deconvolve the bacteria and agar mass spectral signatures. The bacteria mass fraction contributed between 75 and 95% depending on the aerosol generation, with the remaining mass attributed to agar. We present mass spectra of Pseudomonas syringae and Pseudomonas fluorescens bacteria typical for ice-nucleation active bacteria in the atmosphere to facilitate the distinction of airborne bacteria from other constituents in ambient aerosol, e.g. by PMF/ME-2 source apportionment analyses. Nitrogen-containing ions were the most salient feature of the bacteria mass spectra, and a combination of C4 H8 N(+) (m/z 70) and C5 H12 N(+) (m/z 86) may be used as marker ions. PMID:26149110

  20. Bioaerosol detection by aerosol TOF-mass spectrometry: Application of matrix assisted laser desorption/ionisation

    NARCIS (Netherlands)

    Wuijckhuijse, A.L. van; Stowers, M.A.; Kientz, Ch.E.; Marijnissen, J.C.M.; Scarlett, B.

    2000-01-01

    In previous publications the use of an aerosol time of flight mass spectrometer was reported for the on-line measurements of aerosols (Weiss 1997, Kievit 1995). The apparatus is capable of measuring the size as well as the chemical composition, by the use of Laser Desorption/Ionisation (LDI), of an

  1. A Minimal Fragmentation Approach to Real Time Aerosol Mass Spectrometry: A New Tool for Detailed Laboratory Studies of Organic Aerosol Aging

    Science.gov (United States)

    Campuzano-Jost, P.; Hanna, S.; Simpson, E.; Robb, D.; Blades, M. W.; Hepburn, J. W.; Bertram, A. K.

    2005-12-01

    have used almost exclusively a single photon energy (10.5 eV) to ionize all molecules. We have constructed a new real time aerosol mass spectrometer, based on the designs of Su et al. (2004) & Sykes et al. (2002), which incorporates a new, high-powered, fully tunable VUV source (115-190 nm, 6.5-11 eV ionization energy). This enables us to ionize quantitatively with little to no fragmentation almost all atmospherically relevant organic compounds. Coupled with an ion trap where the primary ions can be stored for further structural analysis, this instrument promises to be both universal and sensitive enough to allow for detailed studies of SOA formation as well as the aging of mixed aerosols. References: Allan, J.D., J.L. Jimenez, et al. (2003)."Quantitative sampling using an Aerodyne aerosol mass spectrometer: 1.Techniques of data interpretation and error analysis" J.Geophys.Res. 108(D9) Nash, D.G., X.F. Liu, et al. (2005)."Aerosol particle mass spectrometry with low photon energy laser ionization" Inter.J.Mass Spec. 241(2-3):89 Oktem,B., M.P. Tolocka, et al. (2004)."On-line analysis of organic components in fine and ultrafine particles by photoionization aerosol mass spectrometry" Anal.Chem. 76(2):253 Su, Y.X., M.F. Sipin, et al. (2004)."Development and characterization of an aerosol time-of-flight mass spectrometer with increased detection efficiency" Anal.Chem. 76(3):712 Sykes, D.C., E. Woods, et al. (2002)."Thermal vaporization-vacuum ultraviolet laser ionization time-of-flight mass spectrometry of single aerosol particles" Anal.Chem. 74(9):2048

  2. Chemical Analysis of Organic Aerosols Using Reactive Nanospray Desorption Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Laskin, A.; Laskin, J.; Nizkorodov, S.

    2013-12-01

    Nanospray Desorption Electrospray Ionization (nano-DESI) technique integrated with high resolution mass spectrometry (HR-MS) enables molecular level analysis of organic aerosol (OA) samples. In nano-DESI, analyte is desorbed into a small volume solvent bridge formed between two capillaries positioned in contact with analyte and enables fast and efficient characterization of OA collected on substrates without sample preparation. We report applications of the nano-DESI/HR-MS approach in a number of our recent studies focused on molecular identification of organic compounds in laboratory and in field collected OA samples. Reactive nano-DESI approach where selected reagent is added to the solvent is used for examining the presence of individual species containing specific functional groups and for their quantification within complex mixtures of OA. Specifically, we use the Girard's reagent T (GT) to probe and quantify carbonyl compounds in the SOA mixtures. We estimate for the first time the amounts of dimers and trimers in the SOA mixtures. We found that the most abundant dimer in limonene/O3 SOA was detected at the ˜0.5 pg level and the total amount of dimers and trimers in the analyzed sample was ˜11 pg. Understanding of the OA composition at the molecular level allowed us to identify key aging reactions, including the transformation of carbonyls to imines and carbonyl-imine oligomerization, that may contribute to the formation of brown carbon in the atmosphere.

  3. Determination of particulate lead using aerosol mass spectrometry: MILAGRO/MCMA-2006 observations

    Directory of Open Access Journals (Sweden)

    D. Salcedo

    2010-06-01

    Full Text Available We report the first measurements of particulate lead (Pb from Aerodyne Aerosol Mass Spectrometers, which were deployed in and around Mexico City during the Megacity Initiative: Local and Global Research Observations (MILAGRO/Mexico City Metropolitan Area 2006 (MCMA-2006 field campaigns. The high resolution mass spectrometer of one of the AMS instruments (HR-AMS and the measured isotopic ratios unequivocally prove the detection of Pb in ambient particles. A substantial fraction of the lead evaporated slowly from the vaporizer of the instruments, which is indicative of species with low volatility at 600 °C. A model was developed in order to estimate the ambient particulate Pb entering the AMS from the signals in the "open" and the "closed" (or "background" mass spectrum modes of the AMS. The model suggests the presence of at least two lead fractions with ~25% of the Pb signal exhibiting rapid evaporation (1/e decay constant, τ<0.1 s and ~75% exhibiting slow evaporation (τ~2.4 min at the T0 urban supersite and a different fraction (70% prompt and 30% slow evaporation at a site northwest from the metropolitan area (PEMEX site. From laboratory experiments with pure Pb(NO32 particles, we estimated that the Pb ionization efficiency relative to nitrate (RIEPb is 0.5. Comparison of time series of AMS Pb with other measurements carried out at the T0 supersite during MILAGRO (using Proton Induced X-ray Emission (PIXE, Inductively-Coupled Plasma Mass Spectrometry (ICP-MS and single-particle counts from an Aerosol Time-of-Fight Mass Spectrometer (ATOFMS shows similar levels (for PIXE and ICP-MS and substantial correlation. During part of the campaign, sampling at T0 was alternated every 10 min with an Aerosol Concentrator, which enabled the detection of signals for PbCl+ and PbS+ ions. PbS+ displays the signature of a slowly evaporating species, while PbCl+ appears to arise only

  4. Determination of particulate lead during MILAGRO/MCMA-2006 using Aerosol Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    D. Salcedo

    2010-02-01

    Full Text Available We report the first measurements of particulate lead (Pb from Aerodyne Aerosol Mass Spectrometers, which were deployed in and around Mexico City during the Megacity Initiative: Local and Global Research Observations (MILAGRO/Mexico City Metropolitan Area 2006 (MCMA-2006 field campaigns. The high resolution mass spectrometer of one of the AMS instruments (HR-AMS and the measured isotopic ratios unequivocally prove the detection of Pb in ambient particles. A substantial fraction of the lead evaporated slowly from the vaporizer of the instruments, which is indicative of species with low volatility at 600 °C. A model was developed in order to estimate the ambient particulate Pb entering the AMS from the signals in the "open" and the "closed" (or "background" mass spectrum modes of the AMS. The model suggests the presence of at least two lead fractions with ~25% of the Pb signal exhibiting rapid evaporation (1/e decay constant, τ<0.1 s and ~75% exhibiting slow evaporation (τ~2.4 min at the T0 urban supersite and a different fraction (70% prompt and 30% slow evaporation at a site northwest from the metropolitan area (PEMEX site. From laboratory experiments with pure Pb(NO32 particles, we estimated that the Pb ionization efficiency relative to nitrate (RIEPb is 0.5. Comparison of time series of AMS Pb with other measurements carried out at T0 (using Proton Induced X-ray Emission (PIXE, Inductively-Coupled Plasma Mass Spectrometry (ICP-MS and single-particle counts from an Aerosol Time-of-Fight Mass Spectrometer (ATOFMS shows similar levels (for PIXE and ICP-MS and substantial correlation. During part of the campaign, sampling at T0 was alternated every 10 min with an Aerosol Concentrator, which enabled the detection of signals for PbCl+ and PbS+ ions. PbS+ displays the signature of a slowly evaporating species, while PbCl+ appears to arise only from fast evaporation, which

  5. Mass spectrometry

    DEFF Research Database (Denmark)

    Nyvang Hartmeyer, Gitte; Jensen, Anne Kvistholm; Böcher, Sidsel;

    2010-01-01

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is currently being introduced for the rapid and accurate identification of bacteria. We describe 2 MALDI-TOF MS identification cases - 1 directly on spinal fluid and 1 on grown bacteria. Rapidly obtained r...

  6. Toward new techniques to measure heterogeneous oxidation of aerosol: Electrodynamic Balance-Mass Spectrometry (EDB-MS) and Aerosol X-ray Photoelectron Spectroscopy

    Science.gov (United States)

    Jacobs, M. I.; Heine, N.; Xu, B.; Davies, J. F.; Kirk, B. B.; Kostko, O.; Alayoglu, S.; Wilson, K. R.; Ahmed, M.

    2015-12-01

    The chemical composition and physical properties of aerosol can be changed via heterogeneous oxidation with the OH radical. However, the physical state of the aerosol influences the kinetics of this reaction; liquid particles with a high diffusion coefficient are expected to be well mixed and homogenously oxidized, while oxidation of solid, diffusion-limited aerosol is expected to occur primarily on the surface, creating steep chemical gradients within the particle. We are working to develop several new techniques to study the heterogeneous oxidation of different types of aerosol. We are developing a "modular" electrodynamic balance (EDB) that will enable us to study heterogeneous oxidation at aqueous interfaces using a mass-spectrometer (and potentially other detection techniques). Using a direct analysis in real time (DART) interface, preliminary droplet train measurements have demonstrated single-droplet mass spectrometry to be possible. With long reaction times in our EDB, we will be able to study heterogeneous oxidation of a wide variety of organic species in aqueous droplets. Additionally, we are working to use aerosol photoemission and velocity map imaging (VMI) to study the surface of aerosol particles as they undergo heterogeneous oxidation. With VMI, we're able to collect electrons with a 4π collection efficiency over conventional electron energy analyzers. Preliminary results looking at the ozonolysis of squalene using ultraviolet photoelectron spectroscopy (UPS) show that heterogeneous oxidation kinetic data can be extracted from photoelectron spectra. By moving to X-ray photoemission spectroscopy (XPS), we will determine elemental and chemical composition of the aerosol surface. Thus, aerosol XPS will provide information on the steep chemical gradients that form as diffusion-limited aerosol undergo heterogeneous oxidation.

  7. BioAerosol Mass Spectrometry: Reagentless Detection of Individual Airborne Spores and Other Bioagent Particles Based on Laser Desorption/Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Steele, Paul Thomas [Univ. of California, Davis, CA (United States)

    2004-09-01

    Better devices are needed for the detection of aerosolized biological warfare agents. Advances in the ongoing development of one such device, the BioAerosol Mass Spectrometry (BAMS) system, are described here in detail. The system samples individual, micrometer-sized particles directly from the air and analyzes them in real-time without sample preparation or use of reagents. At the core of the BAMS system is a dual-polarity, single-particle mass spectrometer with a laser based desorption and ionization (DI) system. The mass spectra produced by early proof-of-concept instruments were highly variable and contained limited information to differentiate certain types of similar biological particles. The investigation of this variability and subsequent changes to the DI laser system are described. The modifications have reduced the observed variability and thereby increased the usable information content in the spectra. These improvements would have little value without software to analyze and identify the mass spectra. Important improvements have been made to the algorithms that initially processed and analyzed the data. Single particles can be identified with an impressive level of accuracy, but to obtain significant reductions in the overall false alarm rate of the BAMS instrument, alarm decisions must be made dynamically on the basis of multiple analyzed particles. A statistical model has been developed to make these decisions and the resulting performance of a hypothetical BAMS system is quantitatively predicted. The predictions indicate that a BAMS system, with reasonably attainable characteristics, can operate with a very low false alarm rate (orders of magnitude lower than some currently fielded biodetectors) while still being sensitive to small concentrations of biological particles in a large range of environments. Proof-of-concept instruments, incorporating some of the modifications described here, have already performed well in independent testing.

  8. BioAerosol Mass Spectrometry: Reagentless Detection of Individual Airborne Spores and Other Bioagent Particles Based on Laser Desorption/Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Steele, P T

    2004-07-20

    Better devices are needed for the detection of aerosolized biological warfare agents. Advances in the ongoing development of one such device, the BioAerosol Mass Spectrometry (BAMS) system, are described here in detail. The system samples individual, micrometer-sized particles directly from the air and analyzes them in real-time without sample preparation or use of reagents. At the core of the BAMS system is a dual-polarity, single-particle mass spectrometer with a laser based desorption and ionization (DI) system. The mass spectra produced by early proof-of-concept instruments were highly variable and contained limited information to differentiate certain types of similar biological particles. The investigation of this variability and subsequent changes to the DI laser system are described. The modifications have reduced the observed variability and thereby increased the usable information content in the spectra. These improvements would have little value without software to analyze and identify the mass spectra. Important improvements have been made to the algorithms that initially processed and analyzed the data. Single particles can be identified with an impressive level of accuracy, but to obtain significant reductions in the overall false alarm rate of the BAMS instrument, alarm decisions must be made dynamically on the basis of multiple analyzed particles. A statistical model has been developed to make these decisions and the resulting performance of a hypothetical BAMS system is quantitatively predicted. The predictions indicate that a BAMS system, with reasonably attainable characteristics, can operate with a very low false alarm rate (orders of magnitude lower than some currently fielded biodetectors) while still being sensitive to small concentrations of biological particles in a large range of environments. Proof-of-concept instruments, incorporating some of the modifications described here, have already performed well in independent testing.

  9. Chemical composition, sources, and processes of urban aerosols during summertime in Northwest China: insights from High Resolution Aerosol Mass Spectrometry

    Science.gov (United States)

    Xu, J.; Zhang, Q.; Chen, M.; Ge, X.; Ren, J.; Qin, D.

    2014-06-01

    An aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed along with a Scanning Mobility Particle Sizer (SMPS) and a Multi Angle Absorption Photometers (MAAP) to measure the temporal variations of the mass loading, chemical composition, and size distribution of sub-micrometer particulate matter (PM1) in Lanzhou, northwest China, during 12 July-7 August 2012. The average PM1 mass concentration including non-refractory PM1 (NR-PM1) measured by HR-ToF-AMS and black carbon (BC) measured by MAAP during this study was 24.5 μg m-3 (ranging from 0.86 to 105μg m-3), with a mean composition consisting of 47% organics, 16% sulfate, 12% BC, 11% ammonium, 10% nitrate, and 4% chloride. The organics was consisted of 70% carbon, 21% oxygen, 8% hydrogen, and 1% nitrogen, with the average oxygen-to-carbon ratio (O / C) of 0.33 and organic mass-to-carbon ratio (OM / OC) of 1.58. Positive matrix factorization (PMF) of the high-resolution mass spectra of organic aerosols (OA) identified four distinct factors which represent, respectively, two primary OA (POA) emission sources (traffic and food cooking) and two secondary OA (SOA) types - a fresher, semi-volatile oxygenated OA (SV-OOA) and a more aged, low-volatility oxygenated OA (LV-OOA). Traffic-related hydrocarbon-like OA (HOA) and BC displayed distinct diurnal patterns both with peak at ~07:00-11:00 (BJT: UTC +8) corresponding to the morning rush hours, while cooking OA (COA) peaked during three meal periods. The diurnal profiles of sulfate and LV-OOA displayed a broad peak between ∼07:00-15:00, while those of nitrate, ammonium, and SV-OOA showed a narrower peak at ~08:00-13:00. The later morning and early afternoon peak in the diurnal profiles of secondary aerosol species was likely caused by mixing down of pollutants aloft, which were likely produced in the residual layer decoupled from the boundary layer during night time. The mass spectrum of SV-OOA also showed similarity with that of

  10. Measurement of ambient aerosols in northern Mexico City by single particle mass spectrometry

    Directory of Open Access Journals (Sweden)

    R. C. Moffet

    2008-08-01

    Full Text Available Continuous ambient measurements with aerosol time-of-flight mass spectrometry (ATOFMS were made in an industrial/residential section in the northern part of Mexico City as part of the Mexico City Metropolitan Area-2006 campaign (MCMA-2006. Results are presented for the period of 15–27 March 2006. The submicron size mode contained both fresh and aged biomass burning, aged organic carbon (OC mixed with nitrate and sulfate, elemental carbon (EC, nitrogen-organic carbon, industrial metal, and inorganic NaK inorganic particles. Overall, biomass burning and aged OC particle types comprised 40% and 31%, respectively, of the submicron mode. In contrast, the supermicron mode was dominated by inorganic NaK particle types (42% which represented a mixture of dry lake bed dust and industrial NaK emissions mixed with soot. Additionally, aluminosilicate dust, transition metals, OC, and biomass burning contributed to the supermicron particles. Early morning periods (2–6 a.m. showed high fractions of inorganic particles from industrial sources in the northeast, composed of internal mixtures of Pb, Zn, EC and Cl, representing up to 73% of the particles in the 0.2–3μm size range. A unique nitrogen-containing organic carbon (NOC particle type, peaking in the early morning hours, was hypothesized to be amines from local industrial emissions based on the time series profile and back trajectory analysis. A strong dependence on wind speed and direction was observed in the single particle types that were present during different times of the day. The early morning (3:30–10 a.m. showed the greatest contributions from industrial emissions. During mid to late mornings (7–11 a.m., weak northerly winds were observed along with the most highly aged particles. Stronger winds from the south picked up in the late morning (after 11 a.m., resulting in a decrease in the concentrations of the major aged particle types and an increase in the number fraction of fresh

  11. Direct Surface Analysis of Time-Resolved Aerosol Impactor Samples with Ultrahigh-Resolution Mass Spectrometry

    OpenAIRE

    Fuller, Stephen J.; Zhao, Yongjing; Cliff, Steven S.; Wexler, Anthony S.; Kalberer, Markus

    2012-01-01

    Aerosol particles in the atmosphere strongly influence the Earth?s climate and human health, but the quantification of their effects is highly uncertain. The complex and variable composition of atmospheric particles is a main reason for this uncertainty. About half of the particle mass is organic material, which is very poorly characterized on a molecular level, and therefore it is challenging to identify sources and atmospheric transformation processes. We present here a new combination of t...

  12. Chemical composition, sources, and processes of urban aerosols during summertime in Northwest China: insights from High Resolution Aerosol Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    J. Xu

    2014-06-01

    Full Text Available An aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS was deployed along with a Scanning Mobility Particle Sizer (SMPS and a Multi Angle Absorption Photometers (MAAP to measure the temporal variations of the mass loading, chemical composition, and size distribution of sub-micrometer particulate matter (PM1 in Lanzhou, northwest China, during 12 July–7 August 2012. The average PM1 mass concentration including non-refractory PM1 (NR-PM1 measured by HR-ToF-AMS and black carbon (BC measured by MAAP during this study was 24.5 μg m−3 (ranging from 0.86 to 105μg m−3, with a mean composition consisting of 47% organics, 16% sulfate, 12% BC, 11% ammonium, 10% nitrate, and 4% chloride. The organics was consisted of 70% carbon, 21% oxygen, 8% hydrogen, and 1% nitrogen, with the average oxygen-to-carbon ratio (O / C of 0.33 and organic mass-to-carbon ratio (OM / OC of 1.58. Positive matrix factorization (PMF of the high-resolution mass spectra of organic aerosols (OA identified four distinct factors which represent, respectively, two primary OA (POA emission sources (traffic and food cooking and two secondary OA (SOA types – a fresher, semi-volatile oxygenated OA (SV-OOA and a more aged, low-volatility oxygenated OA (LV-OOA. Traffic-related hydrocarbon-like OA (HOA and BC displayed distinct diurnal patterns both with peak at ~07:00–11:00 (BJT: UTC +8 corresponding to the morning rush hours, while cooking OA (COA peaked during three meal periods. The diurnal profiles of sulfate and LV-OOA displayed a broad peak between ∼07:00–15:00, while those of nitrate, ammonium, and SV-OOA showed a narrower peak at ~08:00–13:00. The later morning and early afternoon peak in the diurnal profiles of secondary aerosol species was likely caused by mixing down of pollutants aloft, which were likely produced in the residual layer decoupled from the boundary layer during night time. The mass spectrum of SV-OOA also showed similarity

  13. Ambient Observations of Organic Nitrogen Compounds in Submicrometer Aerosols in New York Using High Resolution Aerosol Mass Spectrometry

    Science.gov (United States)

    Zhou, S.; Ge, X.; Xu, J.; Sun, Y.; Zhang, Q.

    2015-12-01

    Organic nitrogen (ON) compounds, which include amines, nitriles, organic nitrates, amides, and N-containing aromatic heterocycles, are an important class of compounds ubiquitously detected in atmospheric particles and fog and cloud droplets. Previous studies indicate that these compounds can make up a significant fraction (20-80%) of the total nitrogen (N) content in atmospheric condensed phases and play important roles in new particle formation and growth and affecting the optical and hygroscopicity of aerosols. In this study, we report the observation of ON compounds in submicrometer particles (PM1) at two locations in New York based on measurements using Aerodyne high-resolution time-of-flight mass spectrometer (HR-ToF-AMS). One study was conducted as part of the US Department of Energy funded Aerosol Lifecyle - Intensive Operation Period (ALC-IOP) campaign at Brookhaven National Lab (BNL, 40.871˚N, 72.89˚W) in summer, 2011 and the other was conducted at the Queen's College (QC) in New York City (NYC) in summer, 2009. We observed a notable amount of N-containing organic fragment ions, CxHyNp+ and CxHyOzNp+, in the AMS spectra of organic aerosols at both locations and found that they were mainly associated with amino functional groups. Compared with results from lab experiments, the C3H8N+ at m/z = 58 was primarily attributed to trimethylamine. In addition, a significant amount of organonitrates was observed at BNL. Positive matrix factorization (PMF) analysis of the high resolution mass spectra (HRMS) of organic aerosols identified a unique nitrogen-enriched OA (NOA) factor with elevated nitrogen-to-carbon (N/C) at both BNL and QC. Analysis of the size distributions, volatility profiles, and correlations with external tracer indicates that acid-base reactions of amino compounds with sulfate and acidic gas were mainly responsible for the formation of amine salts. Photochemical production was also observed to play a role in the formation of NOA. Bivariate polar

  14. Mixing state of ambient aerosols in Nanjing city by single particle mass spectrometry

    Science.gov (United States)

    Wang, Honglei; An, Junlin; Shen, Lijuan; Zhu, Bin; Xia, Li; Duan, Qing; Zou, Jianan

    2016-05-01

    To investigate the mixing state and size-resolved aerosol in Nanjing, measurements were carried out for the period 14th January-1st February 2013 by using a Single Particle Aerosol Mass Spectrometer (SPAMS). A total of 10,864,766 particles were sized with vacuum aerodynamic diameter (dva) in the range of 0.2-2.0 μm. Of which, 1,989,725 particles were successfully ionized. Aerosol particles employed for analyzing SPAMS data utilized 96% of the hit particles to identify 5 main particle groups. The particle classes include: K-rich particles (K-CN, K-Nitrate, K-Sulfate and K-Secondary), sodium particles, ammonium particles, carbon-rich particles (OC, EC and OCEC) and heavy-metal particles (Fe-Secondary, Pb-Nitrate, Cu-Mn-Secondary and V-Secondary). EC was the largest contributor with a fraction of 21.78%, followed by K-Secondary (17.87%), K-Nitrate (12.68%) and K-CN (11.25%). High particle level and high RH (relative humidity) are two important factors decreasing visibility in Nanjing. Different particle classes have distinct extinction effects. It anti-correlated well with visibility for the K-secondary, sodium, ammonium, EC, Fe-Secondary and K-Nitrate particles. The proportion of EC particles at 0.65-1.4 μm was up to 25% on haze days and was below 10% on clean days.

  15. Characterization of ambient aerosols in Mexico City during the MCMA-2003 campaign with Aerosol Mass Spectrometry: results from the CENICA Supersite

    Directory of Open Access Journals (Sweden)

    D. Salcedo

    2006-01-01

    Full Text Available An Aerodyne Aerosol Mass Spectrometer (AMS was deployed at the CENICA Supersite, during the Mexico City Metropolitan Area field study (MCMA-2003 from 31 March-4 May 2003 to investigate particle concentrations, sources, and processes. The AMS provides real time information on mass concentration and composition of the non-refractory species in particulate matter less than 1 µm (NR-PM1 with high time and size-resolution. In order to account for the refractory material in the aerosol, we also present estimates of Black Carbon (BC using an aethalometer and an estimate of the aerosol soil component obtained from Proton-Induced X-ray Emission Spectrometry (PIXE analysis of impactor substrates. Comparisons of AMS + BC + soil mass concentration with other collocated particle instruments (a LASAIR Optical Particle Counter, a PM2.5 Tapered Element Oscillating Microbalance (TEOM, and a PM2.5 DustTrak Aerosol Monitor show that the AMS + BC + soil mass concentration is consistent with the total PM2.5 mass concentration during MCMA-2003 within the combined uncertainties. In Mexico City, the organic fraction of the estimated PM2.5 at CENICA represents, on average, 54.6% (standard deviation σ=10% of the mass, with the rest consisting of inorganic compounds (mainly ammonium nitrate and sulfate/ammonium salts, BC, and soil. Inorganic compounds represent 27.5% of PM2.5 (σ=10%; BC mass concentration is about 11% (σ=4%; while soil represents about 6.9% (σ=4%. Size distributions are presented for the AMS species; they show an accumulation mode that contains mainly oxygenated organic and secondary inorganic compounds. The organic size distributions also contain a small organic particle mode that is likely indicative of fresh traffic emissions; small particle modes exist for the inorganic species as well. Evidence suggests that the organic and inorganic species are not always internally mixed, especially in the small modes. The aerosol seems to be neutralized most

  16. Elemental analysis of aerosol organic nitrates with electron ionization high-resolution mass spectrometry

    Directory of Open Access Journals (Sweden)

    A. W. Rollins

    2009-10-01

    Full Text Available Four hydroxynitrates (R(OHR'ONO2 representative of atmospheric volatile organic compound (VOC oxidation products were synthesized, nebulized and sampled into an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS. The resulting mass spectrum was used to evaluate calibration factors for elemental analysis of organic nitrates by AMS, and to determine the distribution of nitrogen in the detected fragments in a search for an AMS signature of organic nitrates. We find that 30% of the detected nitrogen mass is in the NO+ and NO2+ fragments, 12% at NHx+ fragments, 5% at CxHyOzN+ fragments, and 53% at various CxHyN+ fragments. Elemental analysis indicated that nitrogen was detected with higher efficiency than carbon and hydrogen, but oxygen was detected with reduced efficiency compared to previously reported results for a suite of organics which did not include organic nitrates. The results are used to suggest the maximum corrections to ambient O:C and N:C ratios based on AMS measurements.

  17. Molecular composition of biogenic secondary organic aerosols using ultrahigh resolution mass spectrometry: linking laboratory and field studies

    Science.gov (United States)

    Kourtchev, Ivan; Fuller, Stephen; Aalto, Juho; Healy, Robert; Alfara, Rami; Ruuskanen, Taina; Wenger, John; McFiggans, Gordon; Kulmala, Markku; Kalberer, Markus

    2013-04-01

    Biogenic volatile organic compounds (BVOCs) play an important role in atmospheric chemistry and give rise to secondary organic aerosols (SOA), which have effects on climate and human health. Laboratory chamber experiments have been performed during several decades in an attempt to mimic atmospheric SOA formation. However, it is still unclear how close the aerosol particles generated in laboratory experiments resemble atmospheric SOA with respect to their detailed chemical composition. To date, most laboratory experiments have been performed using a single organic precursor (e.g., alpha- or beta-pinene, isoprene) while in the atmosphere a wide range of precursors contribute to SOA, which results most likely in a more complex SOA composition compared to the one-precursor laboratory systems. The objective of this work is to compare laboratory generated SOA from oxidation of BVOCs mixtures and remote ambient samples using ultrahigh-resolution mass spectrometry (UHR-MS) that allows detection of hundreds of individual SOA constituents. We examined aerosol samples from a boreal forest site, Hyytiälä, Finland and determined that a dominant fraction of the detected compounds are reaction products of a multi-component mixture of BVOCs. In the subsequent smog chamber experiments, SOA was generated from the ozonolysis and OH initiated reactions with BVOC mixtures containing species (alpha- and beta-pinene, delta-3-carene, and isoprene) that are most abundant in Hyytiälä's environment. The laboratory experiments were performed at conditions (e.g., RH, aerosol seed, and VOC ratios) that would resemble those at the boreal sampling site during the summer period. The elemental composition of the complex mixtures from laboratory generated SOA samples were compared with field samples using statistical data analysis methods.

  18. Molecular characterization of organic aerosol using nanospray desorption/electrospray ionization mass spectrometry: CalNex 2010 field study

    Science.gov (United States)

    O'Brien, Rachel E.; Laskin, Alexander; Laskin, Julia; Liu, Shang; Weber, Robin; Russell, Lynn M.; Goldstein, Allen H.

    2013-04-01

    Aerosol samples from the CalNex 2010 field study were analyzed using high-resolution mass spectrometry (HR-MS) coupled to a nanospray desorption/electrospray ionization (nano-DESI) source. The samples were collected in Bakersfield, CA on June 22-23, 2010. The chemical formulas of over 850 unique molecular species were detected in the mass range of 50-400 m/z using positive mode ESI of aerosol samples in the 0.18-0.32 μm size range. Our analysis focused on identification of two main groups: compounds containing only carbon, hydrogen, and oxygen (CHO), and nitrogen-containing organic compounds (NOC). The NOC accounted for 40% (by number) of the compounds observed in the afternoon, and for 52% in the early morning samples. By comparing plausible reactant-product pairs, we propose that over 50% of the NOC in each sample could have been formed through reactions transforming carbonyls into imines. The CHO only compounds were dominant in the afternoon suggesting a photochemical source. The average O/C ratios of all observed compounds were fairly consistent throughout the day, ranging from 0.33 in the morning to 0.37 at night. We conclude that both photooxidation and ammonia chemistry may play a role in forming the compounds observed in this mixed urban-rural environment.

  19. Separating refractory and non-refractory particulate chloride and estimating chloride depletion by aerosol mass spectrometry in a marine environment

    OpenAIRE

    I. Nuaaman; Li, S.-M.; K. L. Hayden; Onasch, T. B.; Massoli, P.; D. Sueper; Worsnop, D.R.; Bates, T. S.; Quinn, P. K; McLaren, R.

    2015-01-01

    Aerosol composition and concentration measurements along the coast of California were obtained using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-AMS) onboard the research vessel Atlantis during the CalNex study in 2010. This paper focuses on the measurement of aerosol chloride using the HR-AMS that can be ambiguous in regions with significant quantities of sea salt aerosols. This ambiguity arises due to large differences in the sensitivity of the HR...

  20. Real-time analysis of ambient organic aerosols using aerosol flowing atmospheric-pressure afterglow mass spectrometry (AeroFAPA-MS)

    Science.gov (United States)

    Brüggemann, Martin; Karu, Einar; Stelzer, Torsten; Hoffmann, Thorsten

    2015-04-01

    Organic aerosol accounts for a major fraction of atmospheric aerosols and has implications on the earth's climate and human health. However, due to the chemical complexity its measurement remains a major challenge for analytical instrumentation.1 Here, we present the development, characterization and application of a new soft ionization technique that allows mass spectrometric real-time detection of organic compounds in ambient aerosols. The aerosol flowing atmospheric-pressure afterglow (AeroFAPA) ion source utilizes a helium glow discharge plasma to produce excited helium species and primary reagent ions. Ionization of the analytes occurs in the afterglow region after thermal desorption and results mainly in intact molecular ions, facilitating the interpretation of the acquired mass spectra. In the past, similar approaches were used to detect pesticides, explosives or illicit drugs on a variety of surfaces.2,3 In contrast, the AeroFAPA source operates 'online' and allows the detection of organic compounds in aerosols without a prior precipitation or sampling step. To our knowledge, this is the first application of an atmospheric-pressure glow discharge ionization technique to ambient aerosol samples. We illustrate that changes in aerosol composition and concentration are detected on the time scale of seconds and in the ng-m-3 range. Additionally, the successful application of AeroFAPA-MS during a field study in a mixed forest region in Central Europe is presented. Several oxidation products of monoterpenes were clearly identified using the possibility to perform tandem MS experiments. The acquired data are in agreement with previous studies and demonstrate that AeroFAPA-MS is a suitable tool for organic aerosol analysis. Furthermore, these results reveal the potential of this technique to enable new insights into aerosol formation, growth and transformation in the atmosphere. References: 1) IPCC, 2013: Summary for Policymakers. In: Climate Change 2013: The

  1. Slow aging in Secondary Organic Aerosol observed by Liquid Chromatography coupled with High-Resolution Mass Spectrometry

    Science.gov (United States)

    Bones, D. L.; Bateman, A. P.; Nguyen, T. B.; Laskin, J.; Laskin, A.; Nizkorodov, S.

    2009-12-01

    This study investigated long term changes in the chemical composition of model biogenic secondary organic aerosol (SOA) prepared via ozonolysis of the terpene limonene. This SOA has been observed to turn brown when exposed to NH4+. Our hypothesis is that the chromophoric compounds responsible for this color change are suspected to be imidazole-like or pyridinium-like compounds. These compounds are only present in small relative amounts, hence standard mass spectrometry is insufficient to unambiguously detect these compounds. However, a combination of HPLC and high resolution electrospray ionization mass spectrometry allows assignments of chemical formulae to individual peaks. These and other experiments confirm the presence of N-containing compounds in treated SOA. We are in the process of determining the exact identity of these species by MS/MS methods. LC-MS can also provide information about the polarity of the compounds in SOA. Most compounds in limonene-O3 SOA are polar and are detected at short retention times; peaks suggesting trimeric species appear at longer retention times in the case of fresh SOA, but at shorter times with the bulk of the components for aged SOA. Limonene SOA has been shown to be composed of monomers, dimers, trimers and larger oligomers. The appearance of trimers in specific regions of the chromatogram suggests these species are genuine SOA components and not an artifact of electrospray ionization. Changes in biogenic SOA over time are important because of the propensity of SOA to affect direct and indirect radiative forcing.

  2. Study of a complex environmental mixture by electrospray ionization and laser desorption ionization high resolution mass spectrometry: the cigarette smoke aerosol

    Directory of Open Access Journals (Sweden)

    Vincent Carré

    2015-06-01

    Full Text Available Aerosols from the mainstream cigarette smoke have been analyzed by electrospray ionization (ESI coupled to Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS. Measurements have been conducted in positive ion mode. The chemical composition of cigarette smoke aerosol is significant because it gives insights of one complex indoor environmental mixture. Almost 1300 chemical compositions relative to nitrogen species were successfully determined through the accurate mass measurement and the good ion production of the used technique. The most abundant class of compounds corresponds to N2 one (hydrocarbons with two nitrogen atoms. For other classes, the van Krevelen diagrams ensured to define that other nitrogen and oxygen-nitrogen compounds adopted similar behavior in terms of unsaturation and alkylation range. The detailed composition of cigarette smoke aerosol provided a typical chemical fingerprint from the biomass pyrolysis with tobacco-specific compounds. We examined also the contribution of laser desorption ionization (LDI technique coupled to FTICRMS for the acute analysis of cigarette smoke aerosol. While a part of the chemical composition were found similar to ESI results, LDI achieved a broader range of poly-aromatic compounds and highlight new class compounds as pure hydrocarbon and oxygen-containing species. The combination of ESI and LDI with high resolution mass spectrometry clearly increased significantly the coverage of the “whole composition” of environmental aerosols such as cigarette smoke aerosol.

  3. Elemental ratio measurements of organic compounds using aerosol mass spectrometry: characterization, improved calibration, and implications

    Directory of Open Access Journals (Sweden)

    M. R. Canagaratna

    2014-07-01

    Full Text Available Elemental compositions of organic aerosol (OA particles provide useful constraints on OA sources, chemical evolution, and effects. The Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS is widely used to measure OA elemental composition. This study evaluates AMS measurements of atomic oxygen-to-carbon (O : C, hydrogen-to-carbon (H : C, organic mass-to-organic carbon (OM : OC, and carbon oxidation state (OSC for a vastly expanded laboratory dataset of multifunctional oxidized OA standards. For the expanded standard dataset, the "Aiken-Explicit" method (Aiken et al., 2008, which uses experimentally measured ion intensities at all ions to determine elemental ratios, reproduces known molecular O : C and H : C ratio values within 20% (average absolute value of relative errors and 12% respectively. The more commonly used "Aiken-Ambient" method, which uses empirically estimated H2O+ and CO+ ion intensities to avoid gas phase air interferences at these ions, reproduces O : C and H : C of multifunctional oxidized species within 28% and 14% of known values. These values are systematically biased low, however, with larger biases observed for alcohols and simple diacids. A detailed examination of the H2O+, CO+, and CO2+ fragments in the high-resolution mass spectra of the standard compounds indicates that the Aiken-Ambient method underestimates the CO+ and H2O+ produced from many oxidized species. Combined AMS-vacuum ultraviolet (VUV ionization measurements indicate that these ions are produced by dehydration and decarboxylation on the AMS vaporizer (usually operated at 600 °C. Thermal decomposition is observed to be efficient at vaporizer temperatures down to 200 °C. These results are used together to develop an "Improved-Ambient" elemental analysis method for AMS spectra measured in air. The Improved-Ambient method reduces the systematic biases and reproduces O : C (H : C ratios of individual oxidized standards within 28% (13

  4. Characterization of aromaticity in analogues of titan's atmospheric aerosols with two-step laser desorption ionization mass spectrometry

    Science.gov (United States)

    Mahjoub, Ahmed; Schwell, Martin; Carrasco, Nathalie; Benilan, Yves; Cernogora, Guy; Szopa, Cyril; Gazeau, Marie-Claire

    2016-10-01

    The role of polycyclic aromatic hydrocarbons (PAH) and Nitrogen containing PAH (PANH) as intermediates of aerosol production in the atmosphere of Titan has been a subject of controversy for a long time. An analysis of the atmospheric emission band observed by the Visible and Infrared Mapping Spectrometer (VIMS) at 3.28 μm suggests the presence of neutral polycyclic aromatic species in the upper atmosphere of Titan. These molecules are seen as the counter part of negative and positive aromatics ions suspected by the Plasma Spectrometer onboard the Cassini spacecraft, but the low resolution of the instrument hinders any molecular speciation. In this work we investigate the specific aromatic content of Titan's atmospheric aerosols through laboratory simulations. We report here the selective detection of aromatic compounds in tholins, Titan's aerosol analogs, produced with a capacitively coupled plasma in a N2:CH4 95:5 gas mixture. For this purpose, Two-Step Laser Desorption Ionization Time-of-Flight Mass Spectrometry (L2DI-TOF-MS) technique is used to analyze the so produced analogs. This analytical technique is based on the ionization of molecules by Resonance Enhanced Multi-Photon Ionization (REMPI) using a λ=248 nm wavelength laser which is selective for aromatic species. This allows for the selective identification of compounds having at least one aromatic ring. Our experiments show that tholins contain a trace amount of small PAHs with one to three aromatic rings. Nitrogen containing PAHs (PANHs) are also detected as constituents of tholins. Molecules relevant to astrobiology are detected as is the case of the substituted DNA base adenine.

  5. Evaluation of Aerosol Mixing State Classes in the GISS Modele-matrix Climate Model Using Single-particle Mass Spectrometry Measurements

    Science.gov (United States)

    Bauer, Susanne E.; Ault, Andrew; Prather, Kimberly A.

    2013-01-01

    Aerosol particles in the atmosphere are composed of multiple chemical species. The aerosol mixing state, which describes how chemical species are mixed at the single-particle level, provides critical information on microphysical characteristics that determine the interaction of aerosols with the climate system. The evaluation of mixing state has become the next challenge. This study uses aerosol time-of-flight mass spectrometry (ATOFMS) data and compares the results to those of the Goddard Institute for Space Studies modelE-MATRIX (Multiconfiguration Aerosol TRacker of mIXing state) model, a global climate model that includes a detailed aerosol microphysical scheme. We use data from field campaigns that examine a variety of air mass regimens (urban, rural, and maritime). At all locations, polluted areas in California (Riverside, La Jolla, and Long Beach), a remote location in the Sierra Nevada Mountains (Sugar Pine) and observations from Jeju (South Korea), the majority of aerosol species are internally mixed. Coarse aerosol particles, those above 1 micron, are typically aged, such as coated dust or reacted sea-salt particles. Particles below 1 micron contain large fractions of organic material, internally-mixed with sulfate and black carbon, and few external mixtures. We conclude that observations taken over multiple weeks characterize typical air mass types at a given location well; however, due to the instrumentation, we could not evaluate mass budgets. These results represent the first detailed comparison of single-particle mixing states in a global climate model with real-time single-particle mass spectrometry data, an important step in improving the representation of mixing state in global climate models.

  6. Evaluation of aerosol mixing state classes in the GISS modelE-MATRIX climate model using single-particle mass spectrometry measurements

    Science.gov (United States)

    Bauer, Susanne E.; Ault, Andrew; Prather, Kimberly A.

    2013-09-01

    Aerosol particles in the atmosphere are composed of multiple chemical species. The aerosol mixing state, which describes how chemical species are mixed at the single-particle level, provides critical information on microphysical characteristics that determine the interaction of aerosols with the climate system. The evaluation of mixing state has become the next challenge. This study uses aerosol time-of-flight mass spectrometry (ATOFMS) data and compares the results to those of the Goddard Institute for Space Studies modelE-MATRIX (Multiconfiguration Aerosol TRacker of mIXing state) model, a global climate model that includes a detailed aerosol microphysical scheme. We use data from field campaigns that examine a variety of air mass regimens (urban, rural, and maritime). At all locations, polluted areas in California (Riverside, La Jolla, and Long Beach), a remote location in the Sierra Nevada Mountains (Sugar Pine) and observations from Jeju (South Korea), the majority of aerosol species are internally mixed. Coarse aerosol particles, those above 1 µm, are typically aged, such as coated dust or reacted sea-salt particles. Particles below 1 µm contain large fractions of organic material, internally mixed with sulfate and black carbon, and few external mixtures. We conclude that observations taken over multiple weeks characterize typical air mass types at a given location well; however, due to the instrumentation, we could not evaluate mass budgets. These results represent the first detailed comparison of single-particle mixing states in a global climate model with real-time single-particle mass spectrometry data, an important step in improving the representation of mixing state in global climate models.

  7. The application of single particle aerosol mass spectrometry for the detection and identification of high explosives and chemical warfare agents

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Audrey Noreen [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2006-01-01

    Single Particle Aerosol Mass Spectrometry (SPAMS) was evaluated as a real-time detection technique for single particles of high explosives. Dual-polarity time-of-flight mass spectra were obtained for samples of 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazinane (RDX), and pentaerythritol tetranitrate (PETN); peaks indicative of each compound were identified. Composite explosives, Comp B, Semtex 1A, and Semtex 1H were also analyzed, and peaks due to the explosive components of each sample were present in each spectrum. Mass spectral variability with laser fluence is discussed. The ability of the SPAMS system to identify explosive components in a single complex explosive particle (~1 pg) without the need for consumables is demonstrated. SPAMS was also applied to the detection of Chemical Warfare Agent (CWA) simulants in the liquid and vapor phases. Liquid simulants for sarin, cyclosarin, tabun, and VX were analyzed; peaks indicative of each simulant were identified. Vapor phase CWA simulants were adsorbed onto alumina, silica, Zeolite, activated carbon, and metal powders which were directly analyzed using SPAMS. The use of metal powders as adsorbent materials was especially useful in the analysis of triethyl phosphate (TEP), a VX stimulant, which was undetectable using SPAMS in the liquid phase. The capability of SPAMS to detect high explosives and CWA simulants using one set of operational conditions is established.

  8. Molecular-level Analysis of Size Resolved Secondary Organic Aerosol (SOA) Samples from CALNEX Bakersfield Using High Resolution Mass Spectrometry

    Science.gov (United States)

    O'Brien, R. E.; Laskin, A.; Laskin, J.; Weber, R.; Goldstein, A. H.

    2011-12-01

    This project focuses on analyzing the identities of molecules that comprise oligomers in size resolved aerosol fractions. Since oligomers are generally too large and polar to be measured by typical GC/MS analysis, soft ionization with high resolution mass spectrometry is used to extend the range of observable compounds. Samples collected with a microorifice uniform deposition impactor (MOUDI) during CALNEX Bakersfield in June 2010 have been analyzed with nanospray desorption electrospray ionization (nano-DESI) and an Orbitrap mass spectrometer. The nano-DESI is a soft ionization technique that allows molecular ions to be observed and the Orbitrap has sufficient resolution to determine the elemental composition of almost all species above the detection limit. A large fraction of SOA is made up of high molecular weight oligomers which are thought to form through acid catalyzed reactions of photo-chemically processed volatile organic compounds (VOC). The formation of oligomers must be influenced by the VOCs available, the amount of atmospheric sulfate and nitrate, and the magnitude of photo-chemical processing, among other potential influences. We present the elemental composition of chemical species in SOA in the 0.18 to 0.32 micron size range, providing the first multi-day data set for the study of these oligomers in atmospheric samples. Possible formation pathways and sources of observed compounds will be examined by comparison to other concurrent measurements at the site.

  9. Molecular Characterization of Organic Aerosol Using Nanospray Desorption/Electrospray Ionization Mass Spectrometry: CalNex 2010 field study

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Rachel E.; Laskin, Alexander; Laskin, Julia; Liu, Shang; Weber, Robin; Russell, Lynn; Goldstein, Allen H.

    2013-04-01

    Aerosol samples from the CalNex 2010 field study were analyzed using high resolution mass spectrometry (HR-MS) coupled to a nanospray-desorption/electrospray ionization (nano-DESI) source. The samples were collected in Bakersfield, CA on June 22-23, 2010. The chemical formulas of over 1300 unique molecular species were detected in the mass range of 50-800 m/z. Our analysis focused on identification of two main groups: compounds containing only carbon, hydrogen, and oxygen (CHO only), and nitrogen-containing organic compounds (NOC). The NOC accounted for 35% (by number) of the compounds observed in the afternoon, and for 59% in the early morning samples. By comparing plausible reactant-product pairs, we propose that over 50% of the NOC in each sample could have been formed through reactions transforming carbonyls into imines. The CHO only compounds were dominant in the afternoon suggesting a photochemical source. The average O:C ratios of all observed compounds were fairly consistent throughout the day, ranging from 0.34 in the early morning to 0.37 at night. We conclude that both photooxidation and ammonia chemistry play important roles in forming the compounds observed in this mixed urban-rural environment.

  10. Determination of alkyl amines in atmospheric aerosol particles: a comparison of gas chromatography-mass spectrometry and ion chromatography approaches

    Directory of Open Access Journals (Sweden)

    R.-J. Huang

    2014-03-01

    Full Text Available In recent years low molecular weight alkyl amines have been recognized to play an important role in particle formation and growth in the lower atmosphere. However, major uncertainties are associated with their atmospheric processes, sources and sinks, mostly due to the lack of ambient measurements and the difficulties in accurate quantification of alkyl amines at trace level. In this study, we present the evaluation and optimization of two analytical approaches, i.e., gas chromatography-mass spectrometry (GC-MS and ion chromatography (IC, for the determination of alkyl amines in aerosol particles. Alkyl amines were converted to carbamates through derivatization with isobutyl chloroformate for GC-MS determination. A set of parameters affecting the analytical performances of the GC-MS approach, including reagent amount, reaction time and pH value, was evaluated and optimized. The accuracy is 84.3–99.1%, and the limits of detection obtained are 1.8–3.9 pg. For the IC approach, a solid phase extraction (SPE column was used to separate alkyl amines from interfering cations before IC analysis. 1–2% (v/v of acetone (or 2–4% (v/v of acetonitrile was added to the eluent to improve the separation of alkyl amines on the IC column. The limits of detection obtained are 2.1–15.9 ng and the accuracy is 55.1–103.4%. The lower accuracy can be attributed to evaporation losses of amines during the sample concentration procedure. Measurements of ambient aerosol particle samples collected in Hong Kong show that the GC-MS approach is superior to the IC approach for the quantification of primary and secondary alkyl amines due to its lower detection limits and higher accuracy.

  11. Elemental Composition Analysis to Investigate NOx Effects on Secondary Organic Aerosol from α-Pinene Using Ultrahigh Resolution Mass Spectrometry

    Science.gov (United States)

    Lim, H. J.; Park, J. H.; Babar, Z.

    2015-12-01

    Secondary organic aerosol (SOA) accounts for 20-70% of atmospheric fine aerosol. NOx plays crucial roles in SOA formation and consequently affects the composition and yield of SOA. SOA component speciation is incomplete due to its complex composition of polar oxygenated and multifunctional species. In this study, ultrahigh resolution mass spectrometry (UHR MS) was applied to improve the understanding of NOx effects on biogenic SOA formation by identifying the elemental composition of SOA. Additional research aim was to investigate oligomer components that are considered as a driving force for SOA formation and growth. In this study α-pinene SOA from photochemical reaction was examined. SOA formation was performed in the absence and presence of NOx at dry condition (diagram, van Krevelen diagram, and double bond equivalent values. Substantially large fractions of them are nitrogen containing species. Thousands of individual species of SOA were identified. For SOA in the absence of NOx. intensity normalized mean O/C, H/C, N/C, OM/OC ratios were 0.43, 1.52, 0.02, and 1.68, respectively. For SOA in the presence of NOx, those ratios were 0.52, 0.95, 0.08, and 1.48, respectively. 4 different oligomer formation mechanisms (addition, H abstraction, hydrolysis and de-hydrolysis reaction) were examined on the basis of SOA compositions. Detailed discussion will be presented on the molecular structure and building block of oligomers in SOA as well as the evolution of individual elemental composition by multi-generation reactions. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2011-01350000).

  12. High-Resolution Mass Spectrometry and Molecular Characterization of Aqueous Photochemistry Products of Common Types of Secondary Organic Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Romonosky, Dian E.; Laskin, Alexander; Laskin, Julia; Nizkorodov, Sergey

    2015-03-19

    A significant fraction of atmospheric organic compounds is predominantly found in condensed phases, such as aerosol particles and cloud droplets. Many of these compounds are photolabile and can degrade through direct photolysis or indirect photooxidation processes on time scales that are comparable to the typical lifetimes of aqueous droplets (hours) and particles (days). This paper presents a systematic investigation of the molecular level composition and the extent of aqueous photochemical processing in different types of secondary organic aerosol (SOA) from biogenic and anthropogenic precursors including α-pinene, β-pinene, β-myrcene, d- limonene, α-humulene, 1,3,5-trimethylbenzene, and guaiacol, oxidized by ozone (to simulate a remote atmosphere) or by OH in the presence of NOx (to simulate an urban atmosphere). Chamber- and flow tube-generated SOA samples were collected, extracted in a methanol/water solution, and photolyzed for 1 h under identical irradiation conditions. In these experiments, the irradiation was equivalent to about 3-8 h of exposure to the sun in its zenith. The molecular level composition of the dissolved SOA was probed before and after photolysis with direct-infusion electrospray ionization high-resolution mass spectrometry (ESI-HR-MS). The mass spectra of unphotolyzed SOA generated by ozone oxidation of monoterpenes showed qualitatively similar features, and contained largely overlapping subsets of identified compounds. The mass spectra of OH/NOx generated SOA had more unique visual appearance, and indicated a lower extent of products overlap. Furthermore, the fraction of nitrogen containing species (organonitrates and nitroaromatics) was highly sensitive to the SOA precursor. These observations suggest that attribution of high-resolution mass spectra in field SOA samples to specific SOA precursors should be more straightforward under OH/NOx oxidation conditions compared to the ozone driven oxidation. Comparison of the SOA constituents

  13. Speciation Analysis of 129I and 127I in Aerosols Using Sequential Extraction and Mass Spectrometry Detection

    DEFF Research Database (Denmark)

    Zhang, Luyuan; Hou, Xiaolin; Xu, Sheng

    2015-01-01

    A new analytical method has been developed for speciation analysis of 127I and 129I in aerosols collected on polypropylene (PP) filter paper. Iodide, iodate, NaOH soluble iodine, and insoluble iodine were separated from aerosols using sequential extraction, chromatography separation, and alkaline...... ashing and measured using inductive coupled plasma mass spectrometry (ICP-MS) for 127I and accelerator mass spectrometry (AMS) for 129I. Parameters affecting the leaching efficiency and stability of iodine species, such as leaching time and temperature, amount of alkaline reagent for ashing, ashing...... temperature and time, and iodine protective agent, were investigated and optimized. It was observed that long time water leaching would change inorganic iodine species due to photochemical oxidation of iodide on the PP filter surface. NaOH leaching can only extract less than 60% of iodine from the studied...

  14. Simultaneous analysis of heparosan oligosaccharides by isocratic liquid chromatography with charged aerosol detection/mass spectrometry.

    Science.gov (United States)

    Ji, Xiaohu; Hu, Guixin; Zhang, Qiongyan; Wang, Fengshan; Liu, Chunhui

    2016-11-01

    Uncovering the biological roles of heparosan oligosaccharides requires a simple and robust method for their separation and identification. We reported on systematic investigations of the retention behaviors of synthetic heparosan oligosaccharides on porous graphitic carbon (PGC) column by HPLC with charged aerosol detection. Oligosaccharides were strongly retained by PGC material in water-acetonitrile mobile phase, and eluted by trifluoroacetic acid occurring as narrow peaks. Addition of small fraction of methanol led to better selectivity of PGC to oligosaccharides than acetonitrile modifier alone, presumably, resulting from displacement of methanol to give different chemical environment at the PGC surface. Van't-Hoff plots demonstrated that retention behaviors highly depended on the column temperature and oligosaccharide moieties. By implementing the optimal MeOH content and temperature, a novel isocratic elution method was successfully developed for baseline resolution and identification of seven heparosan oligosaccharides using PGC-HPLC-CAD/MS. This approach allows for rapid analysis of heparosan oligosaccharides from various sources. PMID:27516280

  15. Titan's organic aerosols: Molecular composition and structure of laboratory analogues inferred from pyrolysis gas chromatography mass spectrometry analysis

    Science.gov (United States)

    Morisson, Marietta; Szopa, Cyril; Carrasco, Nathalie; Buch, Arnaud; Gautier, Thomas

    2016-10-01

    Analogues of Titan's aerosols are of primary interest in the understanding of Titan's atmospheric chemistry and climate, and in the development of in situ instrumentation for future space missions. Numerous studies have been carried out to characterize laboratory analogues of Titan aerosols (tholins), but their molecular composition and structure are still poorly known. If pyrolysis gas chromatography mass spectrometry (pyr-GCMS) has been used for years to give clues about their chemical composition, highly disparate results were obtained with this technique. They can be attributed to the variety of analytical conditions used for pyr-GCMS analyses, and/or to differences in the nature of the analogues analyzed, that were produced with different laboratory set-ups under various operating conditions. In order to have a better description of Titan's tholin's molecular composition by pyr-GCMS, we carried out a systematic study with two major objectives: (i) exploring the pyr-GCMS analytical parameters to find the optimal ones for the detection of a wide range of chemical products allowing a characterization of the tholins composition as comprehensive as possible, and (ii) highlighting the role of the CH4 ratio in the gaseous reactive medium on the tholin's molecular structure. We used a radio-frequency plasma discharge to synthetize tholins with different concentrations of CH4 diluted in N2. The samples were pyrolyzed at temperatures covering the 200-700°C range. The extracted gases were then analyzed by GCMS for their molecular identification. The optimal pyrolysis temperature for characterizing the molecular composition of our tholins by GCMS analysis is found to be 600°C. This temperature choice results from the best compromise between the number of compounds released, the quality of the signal and the appearance of pyrolysis artifacts. About a hundred molecules are identified as pyrolysates. A common major chromatographic pattern appears clearly for all the

  16. Investigation of the utility of laser-secondary neutral mass spectrometry for the detection of polyaromatic hydrocarbons in individual atmospheric aerosol particles.

    Science.gov (United States)

    Tyler, Bonnie J; Dambach, Steffen; Galla, Sebastian; Peterson, Richard E; Arlinghaus, Heinrich F

    2012-01-01

    The distribution of polyaromatic hydrocarbons (PAHs) in ambient aerosol particles is of importance to both human health and climate forcing. Although time-of-flight secondary ion mass spectrometry (ToF-SIMS) has proven useful for studying the distribution of organic compounds in individual aerosol particles, it is difficult to detect PAHs at relevant concentrations in individual aerosol particles because of their low ion yield. In this study, we explore the potential of using laser secondary neutral mass spectrometry (Laser-SNMS) to study three PAHs: pyrene, anthracene, and naphthalene. Because of the high volatility of PAHs, a cryostage was required for the analysis to prevent sublimation of the molecules into the vacuum chamber. We studied two laser systems, a 157 nm excimer laser, which is capable of single-photon ionization of the PAHs, and a 193 nm laser, which requires multiphoton ionization. Under optimized conditions for laser power density and primary ion pulse length, 193 nm postionization resulted in a 2-50-fold increase in ion yield over ToF-SIMS. Using the 157 nm laser, the yield was increased by more than 3 orders of magnitude for all 3 PAHs studied. The single-photon postionization process proved superior in terms of both yield enhancement and reduced fragmentation. By using the optimized 157 nm laser system and a cryostage, we were able to detect PAHs on the surface of 2 μm diameter ambient aerosol particles. PMID:21823569

  17. In situ submicron organic aerosol characterization at a boreal forest research station during HUMPPA-COPEC 2010 using soft and hard ionization mass spectrometry

    Science.gov (United States)

    Vogel, A. L.; Äijälä, M.; Corrigan, A. L.; Junninen, H.; Ehn, M.; Petäjä, T.; Worsnop, D. R.; Kulmala, M.; Russell, L. M.; Williams, J.; Hoffmann, T.

    2013-11-01

    The chemical composition of submicron aerosol during the comprehensive field campaign HUMPPA-COPEC 2010 at Hyytiälä, Finland, is presented. The focus lies on online measurements of organic acids, which were achieved by using atmospheric pressure chemical ionization (APCI) ion trap mass spectrometry (IT-MS). These measurements were accompanied by aerosol mass spectrometry (AMS) measurements and Fourier transform infrared spectroscopy (FTIR) of filter samples, all showing a high degree of correlation. The soft ionization mass spectrometer alternated between gas-phase measurements solely and measuring the sum of gas and particle phase. The AMS measurements of C, H and O elemental composition show that the aerosol during the campaign was highly oxidized, which appears reasonable due to high and prolonged radiation during the boreal summer measurement period as well as the long transport times of some of the aerosol. In order to contrast ambient and laboratory aerosol, an average organic acid pattern, measured by APCI-IT-MS during the campaign, was compared to terpene ozonolysis products in a laboratory reaction chamber. Identification of single organic acid species remains a major challenge due to the complexity of the boreal forest aerosol. Unambiguous online species identification was attempted by the combinatorial approach of identifying unique fragments in the MS2 mode of standards, and then comparing these results with MS2 field spectra. During the campaign, unique fragments of limonene-derived organic acids (limonic acid and ketolimononic acid) and of the biomass burning tracer vanillic acid were detected. Other specific fragments (neutral loss of 28 Da) in the MS2 suggest the occurrence of semialdehydes. Furthermore, an approach to determine the average molecular weight of the aerosol is presented. The campaign average organic molecular weight was determined to be 300 g mol-1. However, a plume of aged biomass burning aerosol, arriving at Hyytiälä from Russia

  18. In-situ submicron organic aerosol characterization at a boreal forest research station during HUMPPA-COPEC 2010 using soft and hard ionization mass spectrometry

    Science.gov (United States)

    Vogel, A. L.; Äijälä, M.; Corrigan, A. L.; Junninen, H.; Ehn, M.; Petäjä, T.; Worsnop, D. R.; Kulmala, M.; Russell, L. M.; Williams, J.; Hoffmann, T.

    2013-07-01

    The chemical composition of submicron aerosol during the comprehensive field campaign HUMPPA-COPEC 2010 at Hyytiälä, Finland is presented. The focus lies on online measurements of organic acids, which was achieved by using atmospheric pressure chemical ionization (APCI) ion trap mass spectrometry (IT-MS). These measurements were accompanied by Aerosol Mass Spectrometry (AMS) measurements and Fourier-Transform Infrared Spectroscopy (FTIR) of filter samples, all showing a high degree of correlation. The soft ionization mass spectrometer alternated between gas phase measurements solely and measuring the sum of gas- and particle-phase. The AMS measurements of C, H and O elemental composition show that the aerosol during the campaign was highly oxidized, which appears reasonable due to high and prolonged radiation during the boreal summer measurement period as well as the long transport times of some of the aerosol. In order to contrast ambient and laboratory aerosol, an average organic acid pattern, measured by APCI-IT-MS during the campaign, was compared to terpene ozonolysis products in a laboratory reaction chamber. Identification of single organic acid species remains a major challenge due to the complexity of the boreal forest aerosol. Unambiguous online species identification was attempted by the combinatorial approach of identifying unique fragments in the MS2-mode of standards, and then comparing these results with MS2 field spectra. During the campaign, unique fragments of limonene derived organic acids (limonic acid and ketolimononic acid) and of the biomass burning tracer vanillic acid were detected. Other specific fragments (neutral loss of 28 Da) in the MS2 suggest the occurrence of semialdehydes. Furthermore, an approach to determine the average molecular weight of the aerosol is presented. The campaign average organic molecular weight was determined to be 300 g mol-1. However, a plume of aged biomass burning aerosol, arriving at Hyytiälä from Russia

  19. In-situ submicron organic aerosol characterization at a boreal forest research station during HUMPPA-COPEC 2010 using soft and hard ionization mass spectrometry

    Directory of Open Access Journals (Sweden)

    A. L. Vogel

    2013-07-01

    Full Text Available The chemical composition of submicron aerosol during the comprehensive field campaign HUMPPA-COPEC 2010 at Hyytiälä, Finland is presented. The focus lies on online measurements of organic acids, which was achieved by using atmospheric pressure chemical ionization (APCI ion trap mass spectrometry (IT-MS. These measurements were accompanied by Aerosol Mass Spectrometry (AMS measurements and Fourier-Transform Infrared Spectroscopy (FTIR of filter samples, all showing a high degree of correlation. The soft ionization mass spectrometer alternated between gas phase measurements solely and measuring the sum of gas- and particle-phase. The AMS measurements of C, H and O elemental composition show that the aerosol during the campaign was highly oxidized, which appears reasonable due to high and prolonged radiation during the boreal summer measurement period as well as the long transport times of some of the aerosol. In order to contrast ambient and laboratory aerosol, an average organic acid pattern, measured by APCI-IT-MS during the campaign, was compared to terpene ozonolysis products in a laboratory reaction chamber. Identification of single organic acid species remains a major challenge due to the complexity of the boreal forest aerosol. Unambiguous online species identification was attempted by the combinatorial approach of identifying unique fragments in the MS2-mode of standards, and then comparing these results with MS2 field spectra. During the campaign, unique fragments of limonene derived organic acids (limonic acid and ketolimononic acid and of the biomass burning tracer vanillic acid were detected. Other specific fragments (neutral loss of 28 Da in the MS2 suggest the occurrence of semialdehydes. Furthermore, an approach to determine the average molecular weight of the aerosol is presented. The campaign average organic molecular weight was determined to be 300 g mol−1. However, a plume of aged biomass burning aerosol, arriving at Hyyti

  20. Technical Note: Molecular characterization of aerosol-derived water soluble organic carbon using ultrahigh resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry

    Directory of Open Access Journals (Sweden)

    R. M. Dickhut

    2008-09-01

    Full Text Available Despite the acknowledged relevance of aerosol-derived water-soluble organic carbon (WSOC to climate and biogeochemical cycling, characterization of aerosol WSOC has been limited. Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS was utilized in this study to provide detailed molecular level characterization of the high molecular weight (HMW; m/z>223 component of aerosol-derived WSOC collected from rural sites in Virginia and New York, USA. More than 3000 peaks were detected by ESI FT-ICR MS within a m/z range of 223–600 for each sample. Approximately 86% (Virginia and 78% (New York of these peaks were assigned molecular formulas using only carbon (C, hydrogen (H, oxygen (O, nitrogen (N, and sulfur (S as elemental constituents. H/C and O/C molar ratios were plotted on van Krevelen diagrams and indicated a strong contribution of lignin-like and lipid-like compounds to the aerosol-derived WSOC samples. Approximately 1–4% of the peaks in the aerosol-derived WSOC mass spectra were classified as black carbon (BC on the basis of double bond equivalents calculated from the assigned molecular formulas. In addition, several high-magnitude peaks in the mass spectra of samples from both sites corresponded to molecular formulas proposed in previous secondary organic aerosol (SOA laboratory investigations indicating that SOAs are important constituents of the WSOC. Overall, ESI FT-ICR MS provides a level of resolution adequate for detailed compositional and source information of the HMW constituents of aerosol-derived WSOC.

  1. Mexico City Aerosol Analysis during MILAGRO using High Resolution Aerosol Mass Spectrometry at the Urban Supersite (T0). Part 1: Fine Particle Composition and Organic Source Apportionment

    Energy Technology Data Exchange (ETDEWEB)

    Aiken, Allison; Salcedo, D.; Cubison, Michael J.; Huffman, J.; DeCarlo, Peter; Ulbrich, Ingrid M.; Docherty, Kenneth S.; Sueper, D. T.; Kimmel, Joel; Worsnop, Douglas R.; Trimborn, Achim; Northway, Megan; Stone, Elizabeth A.; Schauer, James J.; Volkamer, Rainer M.; Fortner, Edward; de Foy, B.; Wang, Jian; Laskin, Alexander; Shutthanandan, V.; Zheng, Junsheng; Zhang, Renyi; Gaffney, Jeffrey S.; Marley, Nancy A.; Paredes-Miranda, Guadalupe L.; Arnott, W. P.; Molina, Luisa T.; Sosa, G.; Jimenez, Jose L.

    2009-09-11

    Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and complementary instrumentation. Mass concentrations, diurnal cycles, and size distributions of inorganic and organic species are similar to results from the CENICA supersite in April 2003 with organic aerosol (OA) comprising about half of the fine PM mass. Positive Matrix Factorization (PMF) analysis of the high resolution OA spectra identifies three major components: chemically-reduced urban primary emissions (hydrocarbon-like OA, HOA), oxygenated OA (OOA, mostly secondary OA or SOA), and biomass burning OA (BBOA) that correlates with levoglucosan and acetonitrile. BBOA includes several very large plumes from regional fires and likely also some refuse burning.

  2. Eddy covariance measurements with high-resolution time-of-flight aerosol mass spectrometry: a new approach to chemically-resolved aerosol fluxes

    Directory of Open Access Journals (Sweden)

    D. K. Farmer

    2010-12-01

    Full Text Available Although laboratory studies show that biogenic volatile organic compounds (VOCs yield substantial secondary organic aerosol (SOA, production of biogenic SOA as indicated by upward fluxes has not been conclusively observed over forests. Further, while aerosols are known to deposit to surfaces, few techniques exist to provide chemically-resolved particle deposition fluxes. To better constrain aerosol sources and sinks, we have developed a new technique to directly measure fluxes of chemically-resolved submicron aerosols using the high-resolution time-of-flight aerosol mass spectrometer (HR-AMS in a new, fast eddy covariance mode. This approach takes advantage of the instrument's ability to quantitatively identify both organic and inorganic components, including ammonium, sulphate and nitrate, at a temporal resolution of several Hz. The new approach has been successfully deployed over a temperate ponderosa pine plantation in California during the BEARPEX-2007 campaign, providing both total and chemically resolved non-refractory (NR PM1 fluxes. Average deposition velocity for total NR-PM1 aerosol at noon was 2.05 ± 0.04 mm/s. Using a high resolution measurement of the NH2+ and NH3+ fragments, we demonstrate the first eddy covariance flux measurements of particulate ammonium, which show a noon-time deposition velocity of 1.9 ± 0.7 mm/s and are dominated by deposition of ammonium sulphate.

  3. Isotope dilution mass spectrometry

    Science.gov (United States)

    Heumann, Klaus G.

    1992-09-01

    In the past isotope dilution mass spectrometry (IDMS) has usually been applied using the formation of positive thermal ions of metals. Especially in calibrating other analytical methods and for the certification of standard reference materials this type of IDMS became a routine method. Today, the progress in this field lies in the determination of ultra trace amounts of elements, e.g. of heavy metals in Antarctic ice and in aerosols in remote areas down to the sub-pg g-1 and sub-pg m-3 levels respectively, in the analysis of uranium and thorium at concentrations of a few pg g-1 in sputter targets for the production of micro- electronic devices or in the determination of sub-picogram amounts of230Th in corals for geochemical age determinations and of226Ra in rock samples. During the last few years negative thermal ionization IDMS has become a frequently used method. The determination of very small amounts of selenium and technetium as well as of other transition metals such as vanadium, chromium, molybdenum and tungsten are important examples in this field. Also the measurement of silicon in connection with a re-determination of Avogadro's number and osmium analyses for geological age determinations by the Re/Os method are of special interest. Inductively-coupled plasma mass spectrometry is increasingly being used for multi-element analyses by the isotope dilution technique. Determinations of heavy metals in samples of marine origin are representative examples for this type of multi-element analysis by IDMS. Gas chromatography-mass spectrometry systems have also been successfully applied after chelation of metals (for example Pt determination in clinical samples) or for the determination of volatile element species in the environment, e.g. dimethyl sulfide. However, IDMS--specially at low concentration levels in the environment--seems likely to be one of the most powerful analytical methods for speciation in the future. This has been shown, up to now, for species of

  4. Separating refractory and non-refractory particulate chloride and estimating chloride depletion by aerosol mass spectrometry in a marine environment

    Directory of Open Access Journals (Sweden)

    I. Nuaaman

    2015-01-01

    Full Text Available Aerosol composition and concentration measurements along the coast of California were obtained using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-AMS onboard the research vessel Atlantis during the CalNex study in 2010. This paper focuses on the measurement of aerosol chloride using the HR-AMS that can be ambiguous in regions with significant quantities of sea salt aerosols. This ambiguity arises due to large differences in the sensitivity of the HR-AMS to refractory chloride species (i.e., NaCl and non refractory chloride species (i.e., NH4Cl, HCl, etc.. Using the HR-AMS, the aerosol chloride signal is typically quantified using ion signals for 35Cl+, H35Cl+, 37Cl+ and H37Cl+ (HxCl+. During this study, the highest aerosol chloride signal was observed during sea sweep experiments when the source of the aerosol chloride was NaCl present in artificially generated sea salt aerosols even though the HR-AMS has significantly lower sensitivity to such refractory species. Other prominent ion signals that arise from NaCl salt were also observed at m/z 22.99 for Na+ and m/z 57.96 for Na35Cl+ during both sea sweep experiments and during periods of ambient measurements. Thus, refractory NaCl contributes significantly to the HxCl+ signal, interfering with attempts to quantify non sea salt chloride (nssCl. It was found that during ambient aerosol measurements, the interference in the HxCl+ signal from sea salt chloride (ssCl was as high as 89%, but with a study wide average of 10%. The Na35Cl+ ion signal was found to be a good tracer for NaCl. We outline a method to establish nssCl in the ambient aerosols by subtracting the sea salt chloride (ssCl signal from the HxCl+ signal. The ssCl signal is derived from the Na35Cl+ ion tracer signal and the HxCl+ to Na35Cl+ ratio established from the sea sweep experiments. Ambient submicron concentrations of ssCl were also established using the

  5. Chemical composition of Titan's aerosols analogues characterized with a systematic pyrolysis-gas chromatography-mass spectrometry characterization

    Science.gov (United States)

    Szopa, Cyril; Raulin, Francois; Coll, Patrice; Cabane, Michel; GCMS Team

    2014-05-01

    The in situ chemical characterization of Titan's atmosphere was achieved in 2005 with two instruments present onboard the Huygens atmospheric probe : the Aerosol Collector and Pyrolyzer (ACP) devoted to collect and pyrolyse Titan's aerosols ; the Gas Chromatograph-Mass Spectrometer (GCMS) experiment devoted to analyze gases collected in the atmosphere or coming from the aerosols pyrolysis. The GCMS was developed by Hasso Niemann in the filiation of the quadrupole mass spectrometers he built for several former space missions. The main objectives were to : determine the concentration profile of the most abundant chemical species; seek for minor atmospheric organic species not detected with remote observations ; give a first view of the organic aerosols structure; characterize the condensed volatiles present at the surface (e.g. lakes) in case of survival of the probe to the landing impact. Taking into account for the potential complexity of the gaseous samples to be analyzed, it was decided to couple to the MS analyzer a gas chromatograph capable to separate volatile species from light inorganic molecules and noble gases, to organic compounds including aromatics. This was the first GCMS analyzer that worked in an extraterrestrial environment since the Viking missions on Mars. Even if the GCMS coupling mode did not provide any result of interest, it has been demonstrated to be functional during the Huygens descent. But, the direct MS analysis of the atmosphere, and the pyrolysis-MS analysis of aerosols allowed to make great discoveries which are still of primary importance to describe the Titan's lower atmosphere composition. This contribution aims at presenting this instrument that worked in the Titan's atmosphere, and summarizing the most important discoveries it allowed.

  6. Eddy covariance measurements with high-resolution time-of-flight aerosol mass spectrometry: a new approach to chemically resolved aerosol fluxes

    Directory of Open Access Journals (Sweden)

    D. K. Farmer

    2011-06-01

    Full Text Available Although laboratory studies show that biogenic volatile organic compounds (VOCs yield substantial secondary organic aerosol (SOA, production of biogenic SOA as indicated by upward fluxes has not been conclusively observed over forests. Further, while aerosols are known to deposit to surfaces, few techniques exist to provide chemically-resolved particle deposition fluxes. To better constrain aerosol sources and sinks, we have developed a new technique to directly measure fluxes of chemically-resolved submicron aerosols using the high-resolution time-of-flight aerosol mass spectrometer (HR-AMS in a new, fast eddy covariance mode. This approach takes advantage of the instrument's ability to quantitatively identify both organic and inorganic components, including ammonium, sulphate and nitrate, at a temporal resolution of several Hz. The new approach has been successfully deployed over a temperate ponderosa pine plantation in California during the BEARPEX-2007 campaign, providing both total and chemically resolved non-refractory (NR PM1 fluxes. Average deposition velocities for total NR-PM1 aerosol at noon were 2.05 ± 0.04 mm s−1. Using a high resolution measurement of the NH2+ and NH3+ fragments, we demonstrate the first eddy covariance flux measurements of particulate ammonium, which show a noon-time deposition velocity of 1.9 ± 0.7 mm s−1 and are dominated by deposition of ammonium sulphate.

  7. Highly time-resolved urban aerosol characteristics during springtime in Yangtze River Delta, China: insights from soot particle aerosol mass spectrometry

    Science.gov (United States)

    Wang, Junfeng; Ge, Xinlei; Chen, Yanfang; Shen, Yafei; Zhang, Qi; Sun, Yele; Xu, Jianzhong; Ge, Shun; Yu, Huan; Chen, Mindong

    2016-07-01

    In this work, the Aerodyne soot particle - aerosol mass spectrometer (SP-AMS) was deployed for the first time during the spring of 2015 in urban Nanjing, a megacity in the Yangtze River Delta (YRD) of China, for online characterization of the submicron aerosols (PM1). The SP-AMS enables real-time and fast quantification of refractory black carbon (rBC) simultaneously with other non-refractory species (ammonium, sulfate, nitrate, chloride, and organics). The average PM1 concentration was found to be 28.2 µg m-3, with organics (45 %) as the most abundant component, following by sulfate (19.3 %), nitrate (13.6 %), ammonium (11.1 %), rBC (9.7 %), and chloride (1.3 %). These PM1 species together can reconstruct ˜ 44 % of the light extinction during this campaign based on the IMPROVE method. Chemically resolved mass-based size distributions revealed that small particles especially ultrafine ones (< 100 nm vacuum aerodynamic diameter) were dominated by organics and rBC, while large particles had significant contributions from secondary inorganic species. Source apportionment of organic aerosols (OA) yielded four OA subcomponents, including hydrocarbon-like OA (HOA), cooking-related OA (COA), semi-volatile oxygenated OA (SV-OOA), and low-volatility oxygenated OA (LV-OOA). Overall, secondary organic aerosol (SOA, equal to the sum of SV-OOA and LV-OOA) dominated the total OA mass (55.5 %), but primary organic aerosol (POA, equal to the sum of HOA and COA) can outweigh SOA in the early morning and evening due to enhanced human activities. High OA concentrations were often associated with high mass fractions of POA and rBC, indicating the important role of anthropogenic emissions during heavy pollution events. The diurnal cycles of nitrate, chloride, and SV-OOA both showed good anti-correlations with air temperatures, suggesting their variations were likely driven by thermodynamic equilibria and gas-to-particle partitioning. On the other hand, in contrast to other species

  8. The performance and the characterization of laser ablation aerosol particle time-of-flight mass spectrometry (LAAP-ToF-MS)

    Science.gov (United States)

    Gemayel, Rachel; Hellebust, Stig; Temime-Roussel, Brice; Hayeck, Nathalie; Van Elteren, Johannes T.; Wortham, Henri; Gligorovski, Sasho

    2016-05-01

    Hyphenated laser ablation-mass spectrometry instruments have been recognized as useful analytical tools for the detection and chemical characterization of aerosol particles. Here we describe the performances of a laser ablation aerosol particle time-of-flight mass spectrometer (LAAP-ToF-MS) which was designed for aerodynamic particle sizing using two 405 nm scattering lasers and characterization of the chemical composition of single aerosol particle via ablation/ionization by a 193 nm excimer laser and detection in a bipolar time-of-flight mass spectrometer with a mass resolving power of m/Δm > 600.We describe a laboratory based optimization strategy for the development of an analytical methodology for characterization of atmospheric particles using the LAAP-ToF-MS instrument in combination with a particle generator, a differential mobility analyzer and an optical particle counter. We investigated the influence of particle number concentration, particle size and particle composition on the detection efficiency. The detection efficiency is a product of the scattering efficiency of the laser diodes and the ionization efficiency or hit rate of the excimer laser. The scattering efficiency was found to vary between 0.6 and 1.9 % with an average of 1.1 %; the relative standard deviation (RSD) was 17.0 %. The hit rate exhibited good repeatability with an average value of 63 % and an RSD of 18 %. In addition to laboratory tests, the LAAP-ToF-MS was used to sample ambient air during a period of 6 days at the campus of Aix-Marseille University, situated in the city center of Marseille, France. The optimized LAAP-ToF-MS methodology enables high temporal resolution measurements of the chemical composition of ambient particles, provides new insights into environmental science, and a new investigative tool for atmospheric chemistry and physics, aerosol science and health impact studies.

  9. Mexico City aerosol analysis during MILAGRO using high resolution aerosol mass spectrometry at the urban supersite (T0) - Part 1: Fine particle composition and organic source apportionment

    Energy Technology Data Exchange (ETDEWEB)

    Aiken, A.C.; Wang, J.; Salcedo, D.; Cubison, M. J.; Huffman, J. A.; DeCarlo, P. F.; Ulbrich, I. M.; Docherty, K. S.; Sueper, D.; Kimmel, J. R.; Worsnop, D. R.; Trimborn, A.; Northway, M.; Stone, E. A.; Schauer, J. J.; Volkamer, R. M.; Fortner, E.; de Foy, B.; Laskin, A.; Shutthanandan, V.; Zheng, J.; Zhang, R.; Gaffney, J.; Marley, N. A.; Paredes-Miranda, G.; Arnott, W. P.; Molina, L. T.; Sosa, G.; Jimenez, J. L.

    2009-09-01

    Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and complementary instrumentation. Mass concentrations, diurnal cycles, and size distributions of inorganic and organic species are similar to results from the CENICA supersite in April 2003 with organic aerosol (OA) comprising about half of the fine PM mass. Positive Matrix Factorization (PMF) analysis of the high resolution OA spectra identified three major components: chemically-reduced urban primary emissions (hydrocarbon-like OA, HOA), oxygenated OA (OOA, mostly secondary OA or SOA), and biomass burning OA (BBOA) that correlates with levoglucosan and acetonitrile. BBOA includes several very large plumes from regional fires and likely also some refuse burning. A fourth OA component is a small local nitrogen-containing reduced OA component (LOA) which accounts for 9% of the OA mass but one third of the organic nitrogen, likely as amines. OOA accounts for almost half of the OA on average, consistent with previous observations. OA apportionment results from PMF-AMS are compared to the PM{sub 2.5} chemical mass balance of organic molecular markers (CMB-OMM, from GC/MS analysis of filters). Results from both methods are overall consistent. Both assign the major components of OA to primary urban, biomass burning/woodsmoke, and secondary sources at similar magnitudes. The 2006 Mexico City emissions inventory underestimates the urban primary PM{sub 2.5} emissions by a factor of {approx}4, and it is {approx}16 times lower than afternoon concentrations when secondary species are included. Additionally, the forest fire contribution is at least an order-of-magnitude larger than in the inventory.

  10. Chemical composition, sources, and processes of urban aerosols during summertime in northwest China: insights from high-resolution aerosol mass spectrometry

    Science.gov (United States)

    Xu, J.; Zhang, Q.; Chen, M.; Ge, X.; Ren, J.; Qin, D.

    2014-12-01

    An Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed along with a scanning mobility particle sizer (SMPS) and a multi-angle absorption photometer (MAAP) to measure the temporal variations of the mass loading, chemical composition, and size distribution of submicron particulate matter (PM1) in Lanzhou, northwest China, during 11 July-7 August 2012. The average (PM1 mass concentration including non-refractory (PM1 (NR-(PM1) measured by HR-ToF-AMS and black carbon (BC) measured by MAAP during this study was 24.5 μg m-3 (ranging from 0.86 to 105 μg m-3), with a mean composition consisting of 47% organics, 16% sulfate, 12% BC, 11% ammonium, 10% nitrate, and 4% chloride. Organic aerosol (OA) on average consisted of 70% carbon, 21% oxygen, 8% hydrogen, and 1% nitrogen, with the average oxygen-to-carbon ratio (O / C) of 0.33 and organic mass-to-carbon ratio (OM / OC) of 1.58. Positive matrix factorization (PMF) of the high-resolution organic mass spectra identified four distinct factors which represent, respectively, two primary OA (POA) emission sources (traffic and food cooking) and two secondary OA (SOA) types - a fresher, semi-volatile oxygenated OA (SV-OOA) and a more aged, low-volatility oxygenated OA (LV-OOA). Traffic-related hydrocarbon-like OA (HOA) and BC displayed distinct diurnal patterns, both with peak at ~ 07:00-11:00 (BJT: UTC +8), corresponding to the morning rush hours, while cooking-emission related OA (COA) peaked during three meal periods. The diurnal profiles of sulfate and LV-OOA displayed a broad peak between ~ 07:00 and 15:00, while those of nitrate, ammonium, and SV-OOA showed a narrower peak between ~ 08:00-13:00. The later morning and early afternoon maximum in the diurnal profiles of secondary aerosol species was likely caused by downward mixing of pollutants aloft, which were likely produced in the residual layer decoupled from the boundary layer during nighttime. The mass spectrum of SV-OOA was

  11. Fourier transform mass spectrometry.

    Science.gov (United States)

    Scigelova, Michaela; Hornshaw, Martin; Giannakopulos, Anastassios; Makarov, Alexander

    2011-07-01

    This article provides an introduction to Fourier transform-based mass spectrometry. The key performance characteristics of Fourier transform-based mass spectrometry, mass accuracy and resolution, are presented in the view of how they impact the interpretation of measurements in proteomic applications. The theory and principles of operation of two types of mass analyzer, Fourier transform ion cyclotron resonance and Orbitrap, are described. Major benefits as well as limitations of Fourier transform-based mass spectrometry technology are discussed in the context of practical sample analysis, and illustrated with examples included as figures in this text and in the accompanying slide set. Comparisons highlighting the performance differences between the two mass analyzers are made where deemed useful in assisting the user with choosing the most appropriate technology for an application. Recent developments of these high-performing mass spectrometers are mentioned to provide a future outlook.

  12. Chemistry of α-pinene and naphthalene oxidation products generated in a Potential Aerosol Mass (PAM chamber as measured by acetate chemical ionization mass spectrometry

    Directory of Open Access Journals (Sweden)

    P. S. Chhabra

    2014-07-01

    Full Text Available Recent developments in high resolution, time-of-flight chemical ionization mass spectrometry (HR-ToF-CIMS have made possible the direct detection of atmospheric organic compounds in real-time with high sensitivity and with little or no fragmentation, including low volatility, highly oxygenated organic vapors that are precursors to secondary organic aerosol formation. Here, for the first time, we examine gas-phase O3 and OH oxidation products of α-pinene and naphthalene formed in the PAM flow reactor with an HR-ToF-CIMS using acetate reagent ion chemistry. Integrated OH exposures ranged from 1.2 × 1011 to 9.7 × 1011 molec cm−3 s, corresponding to approximately 1.0 to 7.5 days of equivalent atmospheric oxidation. Measured gas-phase organic acids are similar to those previously observed in environmental chamber studies. For both precursors, we find that acetate-CIMS spectra capture both functionalization (oxygen addition and fragmentation (carbon loss as a function of OH exposure. The level of fragmentation is observed to increase with increased oxidation. We present a method that estimates vapor pressures of organic molecules using the measured O/C ratio, H/C ratio, and carbon number for each compound detected by the CIMS. The predicted condensed-phase SOA average acid yields and O/C and H/C ratios agree within uncertainties with previous AMS measurements and ambient CIMS results. While acetate reagent ion chemistry is used to selectively measure organic acids, in principle this method can be applied to additional reagent ion chemistries depending on the application.

  13. Chemistry of α-pinene and naphthalene oxidation products generated in a Potential Aerosol Mass (PAM) chamber as measured by acetate chemical ionization mass spectrometry

    Science.gov (United States)

    Chhabra, P. S.; Lambe, A. T.; Canagaratna, M. R.; Stark, H.; Jayne, J. T.; Onasch, T. B.; Davidovits, P.; Kimmel, J. R.; Worsnop, D. R.

    2014-07-01

    Recent developments in high resolution, time-of-flight chemical ionization mass spectrometry (HR-ToF-CIMS) have made possible the direct detection of atmospheric organic compounds in real-time with high sensitivity and with little or no fragmentation, including low volatility, highly oxygenated organic vapors that are precursors to secondary organic aerosol formation. Here, for the first time, we examine gas-phase O3 and OH oxidation products of α-pinene and naphthalene formed in the PAM flow reactor with an HR-ToF-CIMS using acetate reagent ion chemistry. Integrated OH exposures ranged from 1.2 × 1011 to 9.7 × 1011 molec cm-3 s, corresponding to approximately 1.0 to 7.5 days of equivalent atmospheric oxidation. Measured gas-phase organic acids are similar to those previously observed in environmental chamber studies. For both precursors, we find that acetate-CIMS spectra capture both functionalization (oxygen addition) and fragmentation (carbon loss) as a function of OH exposure. The level of fragmentation is observed to increase with increased oxidation. We present a method that estimates vapor pressures of organic molecules using the measured O/C ratio, H/C ratio, and carbon number for each compound detected by the CIMS. The predicted condensed-phase SOA average acid yields and O/C and H/C ratios agree within uncertainties with previous AMS measurements and ambient CIMS results. While acetate reagent ion chemistry is used to selectively measure organic acids, in principle this method can be applied to additional reagent ion chemistries depending on the application.

  14. Characterization of ambient aerosols in Mexico City during the MCMA-2003 campaign with Aerosol Mass Spectrometry – Part I: quantification, shape-related collection efficiency, and comparison with collocated instruments

    Directory of Open Access Journals (Sweden)

    D. Salcedo

    2005-06-01

    Full Text Available An Aerodyne Aerosol Mass Spectrometer (AMS was deployed at the CENICA Supersite, while another was deployed in the Aerodyne Mobile Laboratory (AML during the Mexico City Metropolitan Area field study (MCMA-2003 from 31 March–4 May 2003 to investigate particle concentrations, sources, and processes. This is the first of a series of papers reporting the AMS results from this campaign. The AMS provides real time information on mass concentration and composition of the non-refractory species in particulate matter less than 1 µm (NR-PM1 with high time and size-resolution. For the first time, we report field results from a beam width probe, which was used to study the shape and mixing state of the particles and to quantify potential losses of irregular particles due to beam broadening inside the AMS. Data from this probe show that no significant amount of irregular particles was lost due to excessive beam broadening. A comparison of the CENICA and AML AMSs measurements is presented, being the first published intercomparison between two quadrupole AMSs. The speciation, and mass concentrations reported by the two AMSs compared relatively well. The differences found are likely due to the different inlets used in both instruments. In order to account for the refractory material in the aerosol, we also present measurements of Black Carbon (BC using an aethalometer and an estimate of the aerosol soil component obtained from Proton-Induced X-ray Emission Spectrometry (PIXE analysis of impactor substrates. Comparisons of AMS + BC + soil mass concentration with other collocated particle instruments (a LASAIR Optical Particle Counter, a Tapered Element Oscillating Microbalance (TEOM and a DustTrak Aerosol Monitor are also presented. The comparisons show that the AMS + BC + soil mass concentration during MCMA-2003 is a good approximation to the total PM2.5 mass concentration.

  15. Highly time-resolved urban aerosol characteristics during springtime in Yangtze River Delta, China: insights from soot particle aerosol mass spectrometry

    Science.gov (United States)

    Wang, Junfeng; Ge, Xinlei; Chen, Yanfang; Shen, Yafei; Zhang, Qi; Sun, Yele; Xu, Jianzhong; Ge, Shun; Yu, Huan; Chen, Mindong

    2016-07-01

    In this work, the Aerodyne soot particle - aerosol mass spectrometer (SP-AMS) was deployed for the first time during the spring of 2015 in urban Nanjing, a megacity in the Yangtze River Delta (YRD) of China, for online characterization of the submicron aerosols (PM1). The SP-AMS enables real-time and fast quantification of refractory black carbon (rBC) simultaneously with other non-refractory species (ammonium, sulfate, nitrate, chloride, and organics). The average PM1 concentration was found to be 28.2 µg m-3, with organics (45 %) as the most abundant component, following by sulfate (19.3 %), nitrate (13.6 %), ammonium (11.1 %), rBC (9.7 %), and chloride (1.3 %). These PM1 species together can reconstruct ˜ 44 % of the light extinction during this campaign based on the IMPROVE method. Chemically resolved mass-based size distributions revealed that small particles especially ultrafine ones (pollution events. The diurnal cycles of nitrate, chloride, and SV-OOA both showed good anti-correlations with air temperatures, suggesting their variations were likely driven by thermodynamic equilibria and gas-to-particle partitioning. On the other hand, in contrast to other species, sulfate, and LV-OOA concentrations increased in the afternoon, and showed no positive correlations with relative humidity (RH), likely indicating the contribution from photochemical oxidation is dominant over that of aqueous-phase processing for their formations. The bivariate polar plots show that the SV-OOA was formed locally, and the variations of hydrogen-to-carbon (H / C) and oxygen-to-carbon (O / C) ratios in the Van Krevelen space further suggests an evolution pathway of SV-OOA to LV-OOA. Our findings regarding springtime aerosol chemistry in Nanjing may have important implications for the air quality remediation in the densely populated regions.

  16. Forensic Mass Spectrometry

    Science.gov (United States)

    Hoffmann, William D.; Jackson, Glen P.

    2015-07-01

    Developments in forensic mass spectrometry tend to follow, rather than lead, the developments in other disciplines. Examples of techniques having forensic potential born independently of forensic applications include ambient ionization, imaging mass spectrometry, isotope ratio mass spectrometry, portable mass spectrometers, and hyphenated chromatography-mass spectrometry instruments, to name a few. Forensic science has the potential to benefit enormously from developments that are funded by other means, if only the infrastructure and personnel existed to adopt, validate, and implement the new technologies into casework. Perhaps one unique area in which forensic science is at the cutting edge is in the area of chemometrics and the determination of likelihood ratios for the evaluation of the weight of evidence. Such statistical techniques have been developed most extensively for ignitable-liquid residue analyses and isotope ratio analysis. This review attempts to capture the trends, motivating forces, and likely impact of developing areas of forensic mass spectrometry, with the caveat that none of this research is likely to have any real impact in the forensic community unless: (a) The instruments developed are turned into robust black boxes with red and green lights for positives and negatives, respectively, or (b) there are PhD graduates in the workforce who can help adopt these sophisticated techniques.

  17. Online atmospheric pressure chemical ionization ion trap mass spectrometry (APCI-IT-MSn for measuring organic acids in concentrated bulk aerosol – a laboratory and field study

    Directory of Open Access Journals (Sweden)

    J. Williams

    2012-08-01

    Full Text Available The field application of an aerosol concentrator in conjunction with an atmospheric pressure chemical ionization ion trap mass spectrometer (APCI-IT-MS at the boreal forest station SMEAR II at Hyytiälä, Finland, is demonstrated in this study. APCI is a soft ionization technique allowing online measurements of organic acids in the gas and particle phase. The detection limit for the acid species in the particle phase was increased by a factor of 7.5 to 11 (e.g. ~40 ng m−3 for pinonic acid by using the miniature Versatile Aerosol Concentration Enrichment System (mVACES upstream of the mass spectrometer. The APCI-IT-MS was calibrated in the negative ion mode with two biogenic organic acid standards – pinic acid and pinonic acid. Pinic acid was used as a surrogate for the quantification of the total amount of organic acids in the ambient aerosol based on the total signal intensities in the negative ion mode. The results were compared with the total organic signal of a C-ToF-AMS during the HUMPPA-COPEC 2010 field campaign. The campaign average contribution of organic acids measured by APCI-IT-MS to the total sub-micron organic aerosol mass was estimated to be about 60%. Very good correlation between APCI-IT-MS and C-ToF-AMS (Pearson's R = 0.94 demonstrates soft ionization mass spectrometry as a complimentary technique to AMS with electron impact ionization. MS2 studies of specific m/z ratios recorded during the HUMPPA-COPEC 2010 field campaign were compared to MS2 studies of selected monoterpene oxidation products formed in simulation chamber experiments. The comparison of the resulting fragments shows that oxidation products of the main VOCs emitted at Hyytiälä (α-pinene and Δ3-carene cannot account for all of the measured fragments, which illustrates the complexity of ambient aerosol and possibly indicates unidentified or underestimated biogenic SOA precursor in the boreal forest.

  18. Characterization of Organic Nitrate Formation in Limonene Secondary Organic Aerosol using High-Resolution Chemical Ionization Mass Spectrometry

    Science.gov (United States)

    Faxon, Cameron; Hammes, Julia; Peng, Jianfei; Hallquist, Mattias; Pathak, Ravi

    2016-04-01

    Previous work has shown that organic nitrates (RONO2) are prevalent in the boundary layer, and can contribute significantly to secondary organic aerosol formation. Monoterpenes, including limonene, have been shown to be precursors for the formation of these organic nitrates. Limonene has two double bonds, either of which may be oxidized by NO3 or O3. This leads to the generation of products that can subsequently condense or partition into the particle phase, producing secondary organic aerosol. In order to further elucidate the particle and gas phase product distribution of organic nitrates forming from the reactions of limonene and the nitrate radical (NO3), a series of experiments were performed in the Gothenburg Flow Reactor for Oxidation Studies at Low Temperatures (G-FROST), described by previous work. N2O5 was used as the source for NO3 and NO2, and a characterized diffusion source was used to introduce limonene into the flow reactor. All experiments were conducted in the absence of light, and the concentration of limonene was increased step-wise throughout each experiment to modify the ratio of N2O5to limonene. The experiments were conducted such that both limonene- and N2O5-limited regimes were present. Gas and particle phase products were measured using an iodide High-Resolution Time-of-Flight Mass Spectrometer (HR-ToF-CIMS) coupled to a Filter Inlet for Gases and AEROsols (FIGAERO, and particle size and SOA mass concentrations were derived using a Scanning Mobility Particle Sizer (SMPS). CIMS measurement techniques have previously been employed for the measurement of organic nitrate products of such compounds using multiple reagent ions. The use of this instrumentation allowed for the identification of chemical formulas for gas and particle phase species. The findings from the experiments will be presented in terms of the relative gas-particle partitioning of major products and the effects of N2O5/limonene ratios on product distributions. Additionally, a

  19. Insights into secondary organic aerosol formed via aqueous-phase reactions of phenolic compounds based on high resolution mass spectrometry

    Directory of Open Access Journals (Sweden)

    Y. Sun

    2010-02-01

    Full Text Available Recent work has shown that aqueous-phase reactions of phenolic compounds – phenol (C6H6O, guaiacol (C7H8O2, and syringol (C8H10O3 – can form secondary organic aerosol (SOA at high yields. Here we examine the chemical characteristics of this SOA and its formation mechanisms using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-AMS, an Ion Chromatograph (IC, and a Total Organic Carbon (TOC analyzer. The phenolic SOA are highly oxygenated with oxygen-to-carbon (O/C ratios in the range of 0.80–1.06 and carbon oxidation states (=2×O/C–H/C between −0.14 and +0.47. The organic mass-to-carbon (OM/OC ratios determined by the HR-AMS (=2.21���2.55 agree well with values determined based on the SOA mass measured gravimetrically and the OC mass from the TOC analyzer. Both the O/C and OM/OC ratios of the phenolic SOA are similar to the values observed for ambient low-volatility oxygenated/secondary OA (LV-OOA. Oxalate is a minor, but ubiquitous, component of the SOA formed from all three phenolic precursors, accounting for 1.4–5.2% of the SOA mass, with generally higher yields in experiments with H2O2 added as an ·OH source compared to without. The AMS spectra show evidence for the formation of syringol and guaiacol dimers and higher oligomers via C–C and C–O coupling of phenoxyl radicals, which are formed through oxidation pathways such as abstraction of the phenolic hydrogen atom or ·OH addition to the aromatic ring. This latter pathway leads to hydroxylation of the aromatic ring, which is one mechanism that increases the degree of oxidation of the SOA products. Compared to direct photochemical reactions of the phenols, ·OH-initiated reactions favor the formation of smaller oxidation products but less dimers or higher oligomers. Two unique and prominent ions in the syringol and guaiacol SOA spectra,

  20. Insights into secondary organic aerosol formed via aqueous-phase reactions of phenolic compounds based on high resolution mass spectrometry

    Directory of Open Access Journals (Sweden)

    Y. L. Sun

    2010-05-01

    Full Text Available Recent work has shown that aqueous-phase reactions of phenolic compounds – phenol (C6H6O, guaiacol (C7H8O2, and syringol (C8H10O3 – can form secondary organic aerosol (SOA at high yields. Here we examine the chemical characteristics of this SOA and its formation mechanisms using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-AMS, an Ion Chromatography system (IC, and a Total Organic Carbon (TOC analyzer. The phenolic SOA are highly oxygenated with oxygen-to-carbon (O/C ratios in the range of 0.80–1.06 and carbon oxidation states (=2×O/C-H/C between −0.14 and +0.47. The organic mass-to-carbon (OM/OC ratios determined by the HR-AMS (=2.21–2.55 agree well with values determined based on the SOA mass measured gravimetrically and the OC mass from the TOC analyzer. Both the O/C and OM/OC ratios of the phenolic SOA are similar to the values observed for ambient low-volatility oxygenated/secondary OA (LV-OOA. Oxalate is a minor, but ubiquitous, component of the SOA formed from all three phenolic precursors, accounting for 1.4−5.2% of the SOA mass, with generally higher yields in experiments with H2O2 added as an OH source compared to without. The AMS spectra show evidence for the formation of syringol and guaiacol dimers and higher oligomers via C-C and C-O coupling of phenoxyl radicals, which are formed through oxidation pathways such as abstraction of the phenolic hydrogen atom or OH addition to the aromatic ring. This latter pathway leads to hydroxylation of the aromatic ring, which is one mechanism that increases the degree of oxidation of the SOA products. Compared to direct photochemical reactions of the phenols, OH-initiated reactions favor the formation of smaller oxidation products but less dimers or higher oligomers. Two unique and prominent ions in the syringol and guaiacol SOA spectra, m/z 306 (C

  1. Determination of neomycin and related substances in pharmaceutical preparations by reversed-phase high performance liquid chromatography with mass spectrometry and charged aerosol detection.

    Science.gov (United States)

    Stypulkowska, K; Blazewicz, A; Fijalek, Z; Warowna-Grzeskiewicz, M; Srebrzynska, K

    2013-03-25

    A new, simple and repeatable liquid chromatographic method with charged aerosol detection (LC-CAD) for determination of neomycin and related substances has been developed. Analysis of neomycin or other aminoglycosides is problematic due to a lack of chromophores. Universal response of CAD enables direct quantification of neomycin and related substances, for which no reference standard are available. Separation was performed on C18 Hypersil(®) Gold aQ column using water, methanol and heptaflurobutyric acid as mobile phase. Under developed chromatographic conditions all impurities were well separated from neomycin B. Peaks identification was evaluated by electrospray ionization mass spectrometry. The proposed method was validated according to ICH guidelines and applied to the content determination of neomycin and related substances in pharmaceutical preparations.

  2. New insights into secondary organic aerosol from the ozonolysis of α-pinene from combined infrared spectroscopy and mass spectrometry measurements.

    Science.gov (United States)

    Kidd, Carla; Perraud, Véronique; Finlayson-Pitts, Barbara J

    2014-11-01

    Understanding mechanisms of formation, growth and physical properties of secondary organic aerosol (SOA) is central to predicting impacts on visibility, health and climate. It has been known for many decades that the oxidation of monoterpenes by ozone in the gas phase readily forms particles. However, the species responsible for the initial nucleation and the subsequent growth are not well established. Recent studies point to high molecular weight highly oxygenated products with extremely low vapor pressures (ELVOC, extremely low volatility organic compounds) as being responsible for the initial nucleation, with more volatile species contributing to particle growth. We report here the results of studies of SOA formed in the ozonolysis of α-pinene in air at 297 ± 2 K using atmospheric solids analysis probe (ASAP) mass spectrometry, attenuated total reflectance (ATR) Fourier transform infrared spectrometry and proton transfer reaction (PTR) mass spectrometry. Smaller particles are shown to be less volatile and have on average higher molecular mass components compared to larger particles, consistent with recent proposals regarding species responsible for the formation and growth of particles in this system. Thus the signatures of species responsible for particle development at various stages are observable even in particles of several hundred nm diameter. Pinonaldehyde and acetic acid were observed to evaporate from a film of impacted SOA at room temperature, from which the ratio of their diffusion coefficients to the square of the average film thickness, D/l(2), could be obtained. For acetic acid and pinonaldehyde, D/l(2) = 6.8 × 10(-6) s(-1) and 5.0 × 10(-6) s(-1) respectively, the relative magnitudes being consistent with the size difference between acetic acid and pinonaldehyde molecules. Limitations to quantifying the film thickness and hence absolute values of the diffusion coefficient are discussed and highlight a need for novel experimental methods for

  3. Rapid and sensitive quantification of levoglucosan in aerosols by high-performance anion-exchange chromatography with positive electrospray ionization mass spectrometry (HPAEC-positive ESI-MS)

    Science.gov (United States)

    Asakawa, Daichi; Furuichi, Yuko; Yamamoto, Atsushi; Oku, Yuichiro; Funasaka, Kunihiro

    2015-12-01

    A convenient quantification method for underivatized levoglucosan, which is a tracer for biomass burning influenced particulate matter (PM), has been established using high-performance anion-exchange chromatography (HPAEC) coupled to positive electrospray ionization mass spectrometry ((+)ESI-MS). Levoglucosan was chromatographically separated from its isomers (mannosan and galactosan) and detected selectively with positive ESI-MS. Limits of detection and quantification for this method were 0.40 and 1.3 ng mL-1, respectively. A comparison of simultaneous measurements by this method and conventional derivatization gas chromatography/mass spectrometry showed a good linearity with a slope of 1.008 and a determination coefficient of 0.9932. The developed method was applied to ambient suspended particulate matter hourly collected by continuous particulate monitors at 10 stations. The hourly concentration of levoglucosan during August 9-11, 2011, was 1.7-918 ng m-3 and its distribution indicated the transportation of biomass burning aerosols of a forest fire. This is the first report of horizontal distribution of the hourly levoglucosan concentration in Japan.

  4. Online atmospheric pressure chemical ionization ion trap mass spectrometry (APCI-IT-MSn for measuring organic acids in concentrated bulk aerosol – a laboratory and field study

    Directory of Open Access Journals (Sweden)

    J. Williams

    2013-02-01

    Full Text Available The field application of an aerosol concentrator in conjunction with an atmospheric pressure chemical ionization ion trap mass spectrometer (APCI-IT-MS at the boreal forest station SMEAR II at Hyytiälä, Finland, is demonstrated in this study. APCI is a soft-ionization technique allowing online measurements of organic acids in the gas and particle phase. The detection limit for the acid species in the particle phase was improved by a factor of 7.5 to 11 (e.g. ∼40 ng m3 for pinonic acid by using the miniature versatile aerosol concentration enrichment system (mVACES upstream of the mass spectrometer. The APCI-IT-MS was calibrated in the negative ion mode with two biogenic organic acid standards – pinic acid and pinonic acid. Pinic acid was used as a surrogate for the quantification of the total amount of organic acids in the ambient aerosol based on the total signal intensities in the negative ion mode. The results were compared with the total organic signal of a C-ToF-AMS during the HUMPPA-COPEC 2010 field campaign. The campaign average contribution of organic acids measured by APCI-IT-MS to the total submicron organic aerosol mass was estimated to be about 60%, based on the response of pinic acid. Very good correlation between APCI-IT-MS and C-ToF-AMS (Pearson's R = 0.94 demonstrates soft-ionization mass spectrometry as a complimentary technique to AMS with electron impact ionization. MS2 studies of specific m/z ratios recorded during the HUMPPA-COPEC 2010 field campaign were compared to MS2 studies of selected monoterpene oxidation products formed in simulation chamber experiments. The comparison of the resulting fragments shows that oxidation products of the main VOCs emitted at Hyytiälä (α-pinene and Δ3-carene cannot account for all of the measured fragments. Possible explanations for those unaccounted fragments are the presence of unidentified or underestimated biogenic SOA precursors, or that different products are formed by a

  5. Analytical mass spectrometry. Abstracts

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-31

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  6. Analytical mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  7. Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Ryan T.; Marginean, Ioan; Tang, Keqi

    2014-06-13

    Electrospray Ionization (ESI) is a process whereby gas phase ions are created from molecules in solution. As a solution exits a narrow tube in the presence of a strong electric field, an aerosol of charged droplets are is formed that produces gas phase ions as they it desolvates. ESI-MS comprises the creation of ions by ESI and the determination of their mass to charge ratio (m/z) by MS.

  8. Characterizing the secondary organic aerosol products of ozone and α-pinene using ultrahigh-resolution FT-ICR mass spectrometry

    Science.gov (United States)

    Putman, A.; Offenberg, J. H.; Fisseha, R.; Kundu, S.; Rahn, T.; Mazzoleni, L. R.

    2011-12-01

    Three samples of secondary organic aerosol (SOA) were generated by reacting a-pinene and ozone in the presence of variable concentrations of hydroxyl radical scavenging cyclohexane and were characterized by ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT ICR MS). The reactions were performed in the presence of different concentrations of hydroxyl radical scavenger. This provided an opportunity to examine the molecular level differences of SOA. More than 900 chemical formulas for negative ions were identified over the mass range of 100 to 820 u. The experimental reproducibility of the SOA composition and the technical reproducibility of the mass spectra were evaluated. Similar chemical formulas with similar relative abundances were observed in all three experiments. A few exceptions were particular high relative abundance signals such as m/z 357, 367 and 539, whose production efficiency increased in the presence of cyclohexane, and m/z 185, 199, 215, 231 and 261, whose production efficiency decreased in the presence of cyclohexane. In general, the composition of a-pinene SOA was only slightly influenced by the concentration of the hydroxyl radical scavenger, cyclohexane. The negative ion spectra of the SOA contained four groups of peaks over the following mass ranges: 150 aldol condensations or esterification reactions. To provide insight into the formation mechanisms, the molecular structures of selected group II compounds (300 < n < 475) were investigated using ultra-high resolution MS2.

  9. Real time analysis of lead-containing atmospheric particles in Beijing during springtime by single particle aerosol mass spectrometry.

    Science.gov (United States)

    Ma, Li; Li, Mei; Huang, Zhengxu; Li, Lei; Gao, Wei; Nian, Huiqing; Zou, Lilin; Fu, Zhong; Gao, Jian; Chai, Fahe; Zhou, Zhen

    2016-07-01

    Using a single particle aerosol mass spectrometer (SPAMS), the chemical composition and size distributions of lead (Pb)-containing particles with diameter from 0.1 μm to 2.0 μm in Beijing were analyzed in the spring of 2011 during clear, hazy, and dusty days. Based on mass spectral features of particles, cluster analysis was applied to Pb-containing particles, and six major classes were acquired consisting of K-rich, carboneous, Fe-rich, dust, Pb-rich, and Cl-rich particles. Pb-containing particles accounted for 4.2-5.3%, 21.8-22.7%, and 3.2% of total particle number during clear, hazy and dusty days, respectively. K-rich particles are a major contribution to Pb-containing particles, varying from 30.8% to 82.1% of total number of Pb-containing particles, lowest during dusty days and highest during hazy days. The results reflect that the chemical composition and amount of Pb-containing particles has been affected by meteorological conditions as well as the emissions of natural and anthropogenic sources. K-rich particles and carbonaceous particles could be mainly assigned to the emissions of coal combustion. Other classes of Pb-containing particles may be associated with metallurgical processes, coal combustion, dust, and waste incineration etc. In addition, Pb-containing particles during dusty days were first time studied by SPAMS. This method could provide a powerful tool for monitoring and controlling of Pb pollution in real time.

  10. Real time analysis of lead-containing atmospheric particles in Beijing during springtime by single particle aerosol mass spectrometry.

    Science.gov (United States)

    Ma, Li; Li, Mei; Huang, Zhengxu; Li, Lei; Gao, Wei; Nian, Huiqing; Zou, Lilin; Fu, Zhong; Gao, Jian; Chai, Fahe; Zhou, Zhen

    2016-07-01

    Using a single particle aerosol mass spectrometer (SPAMS), the chemical composition and size distributions of lead (Pb)-containing particles with diameter from 0.1 μm to 2.0 μm in Beijing were analyzed in the spring of 2011 during clear, hazy, and dusty days. Based on mass spectral features of particles, cluster analysis was applied to Pb-containing particles, and six major classes were acquired consisting of K-rich, carboneous, Fe-rich, dust, Pb-rich, and Cl-rich particles. Pb-containing particles accounted for 4.2-5.3%, 21.8-22.7%, and 3.2% of total particle number during clear, hazy and dusty days, respectively. K-rich particles are a major contribution to Pb-containing particles, varying from 30.8% to 82.1% of total number of Pb-containing particles, lowest during dusty days and highest during hazy days. The results reflect that the chemical composition and amount of Pb-containing particles has been affected by meteorological conditions as well as the emissions of natural and anthropogenic sources. K-rich particles and carbonaceous particles could be mainly assigned to the emissions of coal combustion. Other classes of Pb-containing particles may be associated with metallurgical processes, coal combustion, dust, and waste incineration etc. In addition, Pb-containing particles during dusty days were first time studied by SPAMS. This method could provide a powerful tool for monitoring and controlling of Pb pollution in real time. PMID:27085059

  11. Hydrogen Exchange Mass Spectrometry.

    Science.gov (United States)

    Mayne, Leland

    2016-01-01

    Hydrogen exchange (HX) methods can reveal much about the structure, energetics, and dynamics of proteins. The addition of mass spectrometry (MS) to an earlier fragmentation-separation HX analysis now extends HX studies to larger proteins at high structural resolution and can provide information not available before. This chapter discusses experimental aspects of HX labeling, especially with respect to the use of MS and the analysis of MS data.

  12. Analysis of sugars and sugar polyols in atmospheric aerosols by chloride attachment in liquid chromatography/negative ion electrospray mass spectrometry.

    Science.gov (United States)

    Wan, Eric C H; Yu, Jian Zhen

    2007-04-01

    Sugars and sugar polyols are relatively abundant groups of water-soluble constituents in atmospheric aerosols. This paper describes a method that uses liquid chromatography-mass spectrometry (LC-MS) to analyze sugars and sugar polyols in atmospheric aerosols, ranging from C3 sugar alcohols to trisaccharides. Postcolumn addition of chloroform in acetonitrile was found to greatly enhance ionization of these compounds by forming chloride adduct ions in the negative-ion mode using electrospray ionization. A gradient elution program starting at 5%:95% H20/acetonitrile and ending at 30%:70% H2O/acetonitrile provides baseline separations of the sugars and sugar polyols on an amino-based carbohydrate column. The detection limits based on quantification of [M + 35Cl]- adduct ions were in the order of 0.1 microM. By eliminating the need for derivatization, this LC-MS based method provides a simpler alternative method to the commonly used and more laborious gas-chromatography based methods. It also has an additional advantage of being able to quantify trisaccharide sugars. The method was applied to analyze 30 ambient samples of fine particulate matter collected at a site away from urban centers in Hong Kong. The sugar compounds positively identified and detected in the ambient samples included four sugar alcohols (glycerol, erythritol, xylitol, and mannitol), three monosacchride sugars (xylose, fructose, and glucose), two disaccharides (sucrose, trehalose), two trisaccharides (melezitose, raffinose), and one anhydrosugar (levoglucosan). The sum of these sugar and sugar polyol compounds ranged from 38 to 1316 ng m(-3), accounting for an average of 1.3% organic carbon mass. Through the use of a principal component analysis of the ambient measurements, the mono- to trisactharide sugars and C3-C5 sugar polyols were identified to be mainly associated with soil/soil microbiota while the anhydrosugar (levoglucosan) was associated with biomass burning. PMID:17438800

  13. Probing Molecular Associations of Secondary Organic Aerosol (SOA) Samples from CalNex 2010 with Nano-DESI High-Resolution Mass Spectrometry

    Science.gov (United States)

    O'Brien, R. E.; Nguyen, T. B.; Laskin, A.; Laskin, J.; Hayes, P. L.; Liu, S.; Jimenez, J. L.; Russell, L. M.; Nizkorodov, S.; Goldstein, A. H.

    2012-12-01

    This project focuses on analyzing the identities of molecules that comprise oligomers in size resolved aerosol fractions. Since oligomers are generally too large and polar to be measured by typical GC/MS analysis, soft ionization with high resolution mass spectrometry is used to extend the range of observable compounds. Samples collected during CalNex 2010 in Bakersfield and Los Angeles and secondary organic aerosol (SOA) produced in a photochemical chamber by photooxidation of diesel (DSL) fuel and isoprene (ISO) under humid, high-NOx conditions have been analyzed with nanospray desorption electrospray ionization (nano-DESI) and a high-resolution Orbitrap mass spectrometer. The nano-DESI is a soft ionization technique that allows molecular ions to be observed and the Orbitrap has sufficient resolution to determine the elemental composition of almost all species above the detection limit. A large fraction of SOA is made up of high molecular weight oligomers which are thought to form through acid catalyzed reactions of photo-chemically processed volatile organic compounds (VOC). The formation of oligomers is influenced by the VOCs available, the amount of atmospheric sulfate and nitrate, and the magnitude of photo-chemical processing, among other potential influences. We present the elemental composition of chemical species in size resolved SOA samples with six-hour time resolution, providing the first time resolved data set for the study of these oligomers in atmospheric samples. We present a comparison of the degree of overlap between the ambient and chamber experiments as a novel method to examine sources for this fraction of SOA. Possible formation pathways and sources of observed compounds are analyzed by comparison to other concurrent measurements at the site.

  14. Characterization of aromaticity in analogues of titan's atmospheric aerosols with two-step laser desorption ionization mass spectrometry

    CERN Document Server

    Mahjoub, Ahmed; Carrasco, Nathalie; Benilan, Yves; Cernogora, Guy; Szopa, Cyril; Gazeau, Marie-Claire

    2016-01-01

    The role of polycyclic aromatic hydrocarbons (PAH) and Nitrogen containing PAH (PANH) as intermediates of aerosol production in the atmosphere of Titan has been a subject of controversy for a long time. An analysis of the atmospheric emission band observed by the Visible and Infrared Mapping Spectrometer (VIMS) at 3.28 micrometer suggests the presence of neutral polycyclic aromatic species in the upper atmosphere of Titan. These molecules are seen as the counter part of negative and positive aromatics ions suspected by the Plasma Spectrometer onboard the Cassini spacecraft, but the low resolution of the instrument hinders any molecular speciation. In this work we investigate the specific aromatic content of Titan's atmospheric aerosols through laboratory simulations. We report here the selective detection of aromatic compounds in tholins, Titan's aerosol analogues, produced with a capacitively coupled plasma in a N2:CH4 95:5 gas mixture. For this purpose, Two-Step Laser Desorption Ionization Time-of-Flight Ma...

  15. Molecular Characterization of Organosulfates in Organic Aerosols from Shanghai and Los Angeles Urban Areas by Nanospray-Desorption Electrospray Ionization High-Resolution Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Shikang; Lu, Xiaohui; Levac, Nicole; Bateman, Adam P.; Nguyen, Tran B.; Bones, David L.; Nizkorodov, Sergey A.; Laskin, Julia; Laskin, Alexander; Yang, Xin

    2014-09-16

    Aerosol samples collected in the urban areas of Shanghai and Los Angeles were analyzed by nanospray-desorption electrospray ionization mass spectrometry (nano-DESI MS) with high mass resolution (m/Δm=100,000). Solvent mixtures of acetonitrile/water and acetonitrile/toluene were used to extract and ionize polar and non-polar compounds, respectively. A diverse mixture of oxygenated hydrocarbons, organosulfates, organonitrates, and organics with reduced nitrogen were detected in the Los Angeles sample. Majority of the organics in the Shanghai sample were detected as organosulfates. The dominant organosulfates in the two samples have distinctly different molecular characteristics. Specifically, organosulfates in the Los Angeles sample were dominated by isoprene- or monoterpene-derived products, while organosulfates of yet unknown origin in the Shanghai sample had distinctive characteristics of long aliphatic carbon chains and low degree of oxidation and unsaturation. The use of acetonitrile/toluene solvent facilitated identification of this type of organosulfates, suggesting they could be missed in previous studies relying on sample extraction using common polar solvents. The high molecular weight and low degree of unsaturation and oxidization of the organosulfates detected in the Shanghai sample suggest that they may act as surfactants, and plausibly affect the surface tension and hygroscopicity of the atmospheric particulate matter. We propose that direct esterification of carbonyl or hydroxyl compounds by sulfates or sulfuric acid in liquid phase could be the formation pathway of these special organosulfates. Finally, long-chain alkanes from vehicle emissions might be their precursors.

  16. "Magic" Ionization Mass Spectrometry.

    Science.gov (United States)

    Trimpin, Sarah

    2016-01-01

    The systematic study of the temperature and pressure dependence of matrix-assisted ionization (MAI) led us to the discovery of the seemingly impossible, initially explained by some reviewers as either sleight of hand or the misinterpretation by an overzealous young scientist of results reported many years before and having little utility. The “magic” that we were attempting to report was that with matrix assistance, molecules, at least as large as bovine serum albumin (66 kDa), are lifted into the gas phase as multiply charged ions simply by exposure of the matrix:analyte sample to the vacuum of a mass spectrometer. Applied heat, a laser, or voltages are not necessary to achieve charge states and ion abundances only previously observed with electrospray ionization (ESI). The fundamentals of how solid phase volatile or nonvolatile compounds are converted to gas-phase ions without added energy currently involves speculation providing a great opportunity to rethink mechanistic understanding of ionization processes used in mass spectrometry. Improved understanding of the mechanism(s) of these processes and their connection to ESI and matrix-assisted laser desorption/ionization may provide opportunities to further develop new ionization strategies for traditional and yet unforeseen applications of mass spectrometry. This Critical Insights article covers developments leading to the discovery of a seemingly magic ionization process that is simple to use, fast, sensitive, robust, and can be directly applied to surface characterization using portable or high performance mass spectrometers. PMID:26486514

  17. "Magic" Ionization Mass Spectrometry

    Science.gov (United States)

    Trimpin, Sarah

    2016-01-01

    The systematic study of the temperature and pressure dependence of matrix-assisted ionization (MAI) led us to the discovery of the seemingly impossible, initially explained by some reviewers as either sleight of hand or the misinterpretation by an overzealous young scientist of results reported many years before and having little utility. The "magic" that we were attempting to report was that with matrix assistance, molecules, at least as large as bovine serum albumin (66 kDa), are lifted into the gas phase as multiply charged ions simply by exposure of the matrix:analyte sample to the vacuum of a mass spectrometer. Applied heat, a laser, or voltages are not necessary to achieve charge states and ion abundances only previously observed with electrospray ionization (ESI). The fundamentals of how solid phase volatile or nonvolatile compounds are converted to gas-phase ions without added energy currently involves speculation providing a great opportunity to rethink mechanistic understanding of ionization processes used in mass spectrometry. Improved understanding of the mechanism(s) of these processes and their connection to ESI and matrix-assisted laser desorption/ionization may provide opportunities to further develop new ionization strategies for traditional and yet unforeseen applications of mass spectrometry. This Critical Insights article covers developments leading to the discovery of a seemingly magic ionization process that is simple to use, fast, sensitive, robust, and can be directly applied to surface characterization using portable or high performance mass spectrometers.

  18. Characterization of aromaticity in analogues of titan's atmospheric aerosols with two-step laser desorption ionization mass spectrometry

    OpenAIRE

    Mahjoub, Ahmed; Schwell, Martin; Carrasco, Nathalie; Benilan, Yves; Cernogora, Guy; Szopa, Cyril; Gazeau, Marie-Claire

    2016-01-01

    The role of polycyclic aromatic hydrocarbons (PAH) and Nitrogen containing PAH (PANH) as intermediates of aerosol production in the atmosphere of Titan has been a subject of controversy for a long time. An analysis of the atmospheric emission band observed by the Visible and Infrared Mapping Spectrometer (VIMS) at 3.28 micrometer suggests the presence of neutral polycyclic aromatic species in the upper atmosphere of Titan. These molecules are seen as the counter part of negative and positive ...

  19. Single event mass spectrometry

    Science.gov (United States)

    Conzemius, Robert J.

    1990-01-16

    A means and method for single event time of flight mass spectrometry for analysis of specimen materials. The method of the invention includes pulsing an ion source imposing at least one pulsed ion onto the specimen to produce a corresponding emission of at least one electrically charged particle. The emitted particle is then dissociated into a charged ion component and an uncharged neutral component. The ion and neutral components are then detected. The time of flight of the components are recorded and can be used to analyze the predecessor of the components, and therefore the specimen material. When more than one ion particle is emitted from the specimen per single ion impact, the single event time of flight mass spectrometer described here furnis This invention was made with Government support under Contract No. W-7405-ENG82 awarded by the Department of Energy. The Government has certain rights in the invention.

  20. Scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and aerosol time-of-flight mass spectrometry (ATOFMS) single particle analysis of metallurgy plant emissions.

    Science.gov (United States)

    Arndt, J; Deboudt, K; Anderson, A; Blondel, A; Eliet, S; Flament, P; Fourmentin, M; Healy, R M; Savary, V; Setyan, A; Wenger, J C

    2016-03-01

    The chemical composition of single particles deposited on industrial filters located in three different chimneys of an iron-manganese (Fe-Mn) alloy manufacturing plant have been compared using aerosol time-of-flight mass spectrometry (ATOFMS) and scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX). Very similar types of particles were observed using both analytical techniques. Calcium-containing particles dominated in the firing area of the sintering unit, Mn and/or Al-bearing particles were observed at the cooling area of the sintering unit, while Mn-containing particles were dominant at the smelting unit. SEM-EDX analysis of particles collected downstream of the industrial filters showed that the composition of the particles emitted from the chimneys is very similar to those collected on the filters. ATOFMS analysis of ore samples was also performed to identify particulate emissions that could be generated by wind erosion and manual activities. Specific particle types have been identified for each emission source (chimneys and ore piles) and can be used as tracers for source apportionment of ambient PM measured in the vicinity of the industrial site.

  1. Nano-objects emitted during maintenance of common particle generators: direct chemical characterization with aerosol mass spectrometry and implications for risk assessments

    International Nuclear Information System (INIS)

    Nanotechnology gives us materials with enhanced or completely new properties. At the same time, inhalation of manufactured nano-objects has been related to an array of adverse biological effects. We characterized particle emissions, which occurred during maintenance of common metal nanoparticle generators and contrasted the properties of the emitted particles with those originally produced by the generators. A new approach using online aerosol mass spectrometry (AMS), for time- and size-resolved measurements of the particle chemical composition, was applied in combination with more conventional techniques for particle sampling and analysis, including electron microscopy. Emissions during maintenance work, in terms of mass and surface area concentration in the size range of 0.02–10 μm, were dominated by large agglomerates (1–5 μm). With AMS, we show that the particle composition depends on both generator type and maintenance task being performed and that the instrument can be used for highly time-resolved selective studies of metal nanoparticle emissions. The emitted agglomerates have a relatively high probability to be deposited in the lower respiratory tract, since the mean particle diameter coincided with a peak in the lung deposition curve. Each of these agglomerates consisted of a very high number (103–105/agglomerate) of nanometer-sized primary particles originating from the particle synthesis process. This made them possess large surface areas, one of the key properties in nanotoxicology. Similar agglomerates may be emitted in a wide range of processes when nanoparticles are manufactured or handled. The fate of such agglomerates, once deposited in the respiratory tract, is unknown and should therefore be considered in future particle toxicological studies. Our results highlight the importance of including micrometer-sized particles in exposure and emission assessments

  2. Nano-objects emitted during maintenance of common particle generators: direct chemical characterization with aerosol mass spectrometry and implications for risk assessments

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Patrik T., E-mail: patrik.nilsson@design.lth.se; Isaxon, Christina [Lund University, Ergonomics and Aerosol Technology (Sweden); Eriksson, Axel C. [Lund University, Nuclear Physics (Sweden); Messing, Maria E. [Lund University, Solid State Physics (Sweden); Ludvigsson, Linus; Rissler, Jenny [Lund University, Ergonomics and Aerosol Technology (Sweden); Hedmer, Maria; Tinnerberg, Håkan [Lund University, Division of Occupational and Environmental Medicine, Department of Laboratory Medicine (Sweden); Gudmundsson, Anders [Lund University, Ergonomics and Aerosol Technology (Sweden); Deppert, Knut [Lund University, Solid State Physics (Sweden); Bohgard, Mats; Pagels, Joakim H. [Lund University, Ergonomics and Aerosol Technology (Sweden)

    2013-11-15

    Nanotechnology gives us materials with enhanced or completely new properties. At the same time, inhalation of manufactured nano-objects has been related to an array of adverse biological effects. We characterized particle emissions, which occurred during maintenance of common metal nanoparticle generators and contrasted the properties of the emitted particles with those originally produced by the generators. A new approach using online aerosol mass spectrometry (AMS), for time- and size-resolved measurements of the particle chemical composition, was applied in combination with more conventional techniques for particle sampling and analysis, including electron microscopy. Emissions during maintenance work, in terms of mass and surface area concentration in the size range of 0.02–10 μm, were dominated by large agglomerates (1–5 μm). With AMS, we show that the particle composition depends on both generator type and maintenance task being performed and that the instrument can be used for highly time-resolved selective studies of metal nanoparticle emissions. The emitted agglomerates have a relatively high probability to be deposited in the lower respiratory tract, since the mean particle diameter coincided with a peak in the lung deposition curve. Each of these agglomerates consisted of a very high number (10{sup 3}–10{sup 5}/agglomerate) of nanometer-sized primary particles originating from the particle synthesis process. This made them possess large surface areas, one of the key properties in nanotoxicology. Similar agglomerates may be emitted in a wide range of processes when nanoparticles are manufactured or handled. The fate of such agglomerates, once deposited in the respiratory tract, is unknown and should therefore be considered in future particle toxicological studies. Our results highlight the importance of including micrometer-sized particles in exposure and emission assessments.

  3. Nanopore Mass Spectrometry

    Science.gov (United States)

    Bush, Joseph; Mihovilovic, Mirna; Maulbetsch, William; Frenchette, Layne; Moon, Wooyoung; Pruitt, Cole; Bazemore-Walker, Carthene; Weber, Peter; Stein, Derek

    2013-03-01

    We report on the design, construction, and characterization of a nanopore-based ion source for mass spectrometry. Our goal is to field-extract ions directly from solution into the high vacuum to enable unit collection efficiency and temporal resolution of sequential ion emissions for DNA sequencing. The ion source features a capillary whose tip, measuring tens to hundreds of nanometers in inner diameter, is situated in the vacuum ~ 1.5 cm away from an extractor electrode. The capillary was filled with conductive solution and voltage-biased relative to the extractor. Applied voltages of hundreds of volts extracted tens to hundreds of nA of current from the tip. A mass analysis of the extracted ions showed primarily singly charged clusters comprising the cation or anion solvated by several solvent molecules. Our interpretation of these results, based on the works of Taylor and of de la Mora, is that the applied electric stresses distort the fluid meniscus into a Taylor cone, where electric fields reach ~ 1V/nm and induce significant ion evaporation. Accordingly, the abundances of extracted ionic clusters resemble a Boltzmann distribution. This work was supported by NIH grant NHGRI 1R21HG005100-01.

  4. Negative chemical ionization mass spectrometry

    International Nuclear Information System (INIS)

    This thesis describes some aspects of Negative Chemical Ionization (NCI) mass spectrometry. The reasons for the growing interest in NCI are: (i) to extend the basic knowledge of negative ions and their reactions in the gas phase; (ii) to investigate whether or not this knowledge of negative ions can be used successfully to elucidate the structure of molecules by mass spectrometry. (Auth.)

  5. Evaluating the degree of oxygenation of organic aerosol during foggy and hazy days in Hong Kong using high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS

    Directory of Open Access Journals (Sweden)

    Y. J. Li

    2013-02-01

    Full Text Available The chemical characteristics of organic aerosol (OA are still poorly constrained. Here we present observation results of the degree of oxygenation of OA based on high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS measurements made at a coastal site in Hong Kong from late April to the end of May in 2011. Two foggy periods and one hazy period were chosen for detailed analysis to compare the changes in the degree of oxygenation of OA due to different processes. The Extended Aerosol Inorganic Model (E-AIM predicted a fine particle liquid water content (LWCfp up to 85 μg m−3 during the foggy days. Particle concentration as measured by HR-ToF-AMS was up to 60 μg m−3 during the hazy days and up to 30 μg m−3 during the foggy days. The degree of oxygenation of OA, as indicated by several parameters including the fraction of m/z 44 in organic mass spectra (f44, the elemental ratio of oxygen to carbon (O : C, and the carbon oxidation state (OSc, was evaluated against the odd oxygen (Ox concentration, LWCfp, ionic strength (IS, and in-situ pH (pHis. Results suggest that the high concentration of OA (on average 11 μg m−3 and the high degree of oxygenation (f44 = 0.15, O : C = 0.51, and OSc = −0.31 during the hazy period were mainly due to gas-phase oxidation. During the foggy periods with low photochemical activities, the degree of oxygenation of OA was almost as high as that on the hazy days and significantly higher than that during non-foggy/non-hazy days. However, the OA evolved quite differently in the two foggy periods. The first foggy period in late April saw a larger LWCfp and a lower Ox concentration and the OA was made up of ~ 20% semi

  6. A molecular-level approach for characterizing water-insoluble components of ambient organic aerosol particulates using ultra-high resolution mass spectrometry

    Directory of Open Access Journals (Sweden)

    A. S. Willoughby

    2014-04-01

    Full Text Available The chemical composition of organic aerosols in the atmosphere is strongly influenced by human emissions, and the effect these have on the environment, human health, and climate change is determined by the molecular nature of these chemical species. The complexity of organic aerosol samples limits the ability to study the chemical composition, and, therefore, the associated properties and the impacts they have. Many studies address the water-soluble fraction of organic aerosols, and have had much success in identifying specific molecular formulas for thousands of compounds present. However, little attention is given to the water-insoluble portion, which can contain most of the fossil material that is emitted through human activity. Here we compare the organic aerosols present in water extracts and organic solvent extracts (pyridine and acetonitrile of an ambient aerosol sample collected in a rural location that is impacted by natural and anthropogenic emission sources. A semi-quantitative method was developed using proton nuclear magnetic resonance spectroscopy to determine that the amount of organic matter extracted by pyridine is comparable to that of water. Electrospray ionization Fourier transform ion cyclotron resonance mass spectra show that pyridine extracts a molecularly unique fraction of organic matter compared to water or acetonitrile, which extract chemically similar organic matter components. The molecular formulas unique to pyridine were less polar, more aliphatic, and reveal formulas containing sulfur to be an important component of insoluble aerosol organic matter.

  7. Correlations in the chemical composition of rural background atmospheric aerosol in the UK determined in real time using time-of-flight mass spectrometry.

    Science.gov (United States)

    Beddows, David C S; Donovan, Robert J; Harrison, Roy M; Heal, Mathew R; Kinnersley, Robert P; King, Martin D; Nicholson, David H; Thompson, Katherine C

    2004-02-01

    An aerosol time-of-flight mass spectrometer (ATOFMS) was used to determine, in real time, the size and chemical composition of individual particles in the atmosphere at the remote inland site of Eskdalemuir, Scotland. A total of 51,980 particles, in the size range 0.3-7.4 microm, were detected between the 25th and 30th June 2001. Rapid changes in the number density, size and chemical composition of the atmospheric aerosol were observed. These changes are attributed to two distinct types of air mass; a polluted air mass that had passed over the British mainland before reaching Eskdalemuir, interposed between two cleaner air masses that had arrived directly from the sea. Such changes in the background aerosol could clearly be very important to studies of urban aerosols and attempts at source apportionment. The results of an objective method of data analysis are presented. Correlations were sought between the occurrence of: lithium, potassium, rubidium, caesium, beryllium, strontium, barium, ammonium, amines, nitrate, nitrite, boron, mercury, sulfate, phosphate, fluorine, chlorine, bromine, iodine and carbon (both elemental and organic hydrocarbon) in both fine (d 2.5 microm) particle fractions. Several previously unreported correlations were observed, for instance between the elements lithium, beryllium and boron. The results suggest that about 2 in 3 of all fine particles (by number rather than by mass), and 1 in 2 of all coarse particles containing carbon, consisted of elemental carbon rather than organic hydrocarbon (although a bias in the sensitivity of the ATOFMS could have affected these numbers). The ratio of the number of coarse particles containing nitrate anions to the number of particles containing chloride anions exceeded unity when the air mass had travelled over the British mainland. The analysis also illustrates that an air mass of marine origin that had travelled slowly over agricultural land can accumulate amines and ammonium.

  8. Mass Spectrometry of Halopyrazolium Salts

    DEFF Research Database (Denmark)

    Larsen, Elfinn; Egsgaard, Helge; Pande, U. C.;

    1983-01-01

    Eleven halogen substituted 1-methyl-2-phenylpyrazolium bromides or chlorides were investigated by field desorption, field ionization, and electron impact mass spectrometry. Dealkylation was found to be the predominant thermal decomposition. An exchange between covalent and ionic halogen prior...

  9. Linear electric field mass spectrometry

    Science.gov (United States)

    McComas, David J.; Nordholt, Jane E.

    1992-01-01

    A mass spectrometer and methods for mass spectrometry. The apparatus is compact and of low weight and has a low power requirement, making it suitable for use on a space satellite and as a portable detector for the presence of substances. High mass resolution measurements are made by timing ions moving through a gridless cylindrically symmetric linear electric field.

  10. Elemental characterization of PM2.5 urban aerosol samples collected in Budapest (Hungary) by sector-field inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Complete text of publication follows. Nowadays, the investigation of PM10 urban aerosols in the EU member countries has become a daily routine task. The real challenge represents the characterization of aerosol particles with lower aerodynamic diameter than 10 micrometers as they do not deposit in the upper respiratory system and can even cause neoplasms. Considering the possible health effects, present investigation focuses on the PM2.5 fractions. This finer fraction is more characteristic for the anthropogenic pollutants originating from high temperature combustion processes. Therefore, PM2.5 urban aerosols were collected monthly for 96 consecutive hours on Whatmam QM-A quartz filters in a 3-month-long sampling campaign from three different representative points of Budapest (Szena Square, Gilice Square, nearby the urban waste incinerator of Kaposztasmegyer) with a Greenlab DHA-80 high-volume sampler at 500 m3/min. Twenty-three elements (Ag, Bi, Cd, Co, Cr, Cu, Fe, Ga, Li, Mn, Ni, Pt, Pb, Rb, Sb, Sn, Sr, Te, Tl, U, Mo, V, Zn) were determined after microwave-assisted aqua regia digestion by an Element2 sector-field inductively coupled plasma mass spectrometer (SF-ICP-MS). Since the bioavailability of elements is an important factor by studying their health effects, the water soluble part of the elements was also determined by SF-ICP-MS after sonication in a water bath. In addition, the TOC and TIC content of these urban aerosol fractions were determined with an TOC/N Analytik Jena equipment.

  11. Mass spectrometry. [in organic chemistry

    Science.gov (United States)

    Burlingame, A. L.; Shackleton, C. H. L.; Howe, I.; Chizhov, O. S.

    1978-01-01

    A review of mass spectrometry in organic chemistry is given, dealing with advances in instrumentation and computer techniques, selected topics in gas-phase ion chemistry, and applications in such fields as biomedicine, natural-product studies, and environmental pollution analysis. Innovative techniques and instrumentation are discussed, along with chromatographic-mass spectrometric on-line computer techniques, mass spectral interpretation and management techniques, and such topics in gas-phase ion chemistry as electron-impact ionization and decomposition, photoionization, field ionization and desorption, high-pressure mass spectrometry, ion cyclotron resonance, and isomerization reactions of organic ions. Applications of mass spectrometry are examined with respect to bio-oligomers and their constituents, biomedically important substances, microbiology, environmental organic analysis, and organic geochemistry.

  12. Miniature Sensor for Aerosol Mass Measurements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR project seeks to develop a miniature sensor for mass measurement of size-classified aerosols. A cascade impactor will be used to classify aerosol sample...

  13. Instrumentation for mass spectrometry: 1997

    Energy Technology Data Exchange (ETDEWEB)

    McLuckey, S.A.

    1997-08-01

    All mass spectrometry experiments involve the manipulation of material, an interface with the mass spectrometer, ionization, ion manipulation/analysis, detection and data collection/reduction. Each of these elements involve instrumentation. The wide range of species now amenable to mass spectrometry and the diverse areas of physical science in which it plays a role have led to a seemingly unlimited array of instrumental combinations. However, only a limited number of mass analyzers, and their combinations, dominate. The dominant analyzers include time-of-flight, Fourier transform ion cyclotron resonance, the Paul trap, the mass filter, and the sector mass spectrometer. Why there are so few (or so many, depending upon one`s point of view) can be understood upon consideration of a set of mass analyzer figures of merit. These include mass resolution, mass accuracy, mass range, dynamic range, abundance sensitivity, precision, efficiency, speed, MS{sup n} capability, compatibility with the ionizer, cost, and size. The most appropriate form of mass spectrometry is determined by the priorities of the particular measurement placed on the various mass analyzer characteristics and the relative strengths of the analyzers in meeting the requirements. Each of the analyzer types has a unique set of figures of merit that makes it optimally suited for particular applications. This paper discusses these figures of merit, provides data illustrating recent developments for each analyzer type, and gives the figures of merit of each type of analyzer as they stand in 1997. 101 refs., 24 figs.

  14. ARTICLES: Influence Factors on Particle Growth for On-line Aerosol Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry

    Science.gov (United States)

    Xia, Wei-wei; Ti, Ru-fang; Zhang, Zi-Iiang; Zheng, Hai-yang; Fang, Li

    2010-06-01

    An evaporation/condensation flow cell was developed and interfaced with the matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometer for on-line bioaerosol detection and characterization, which allows matrix addition by condensation onto the laboratory-generated bioaerosol particles. The final coated particle exiting from the condenser is then introduced into the aerodynamic particle sizer spectrometer or home-built aerosol laser time-of-flight mass spectrometer, and its aerodynamic size directly effects on the matrix-to-analyte molar ratio, which is very important for MALDI technique. In order to observe the protonated analyte molecular ion, and then determine the classification of biological aerosols, the matrix-to-analyte molar ratio must be appropriate. Four experimental parameters, including the temperature of the heated reservoir, the initial particle size, its number concentration, and the matrix material, were tested experimentally to analyze their influences on the final particle size. This technique represents an on-line system of detection that has the potential to provide rapid and reliable identification of airborne biological aerosols.

  15. Symposium on accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    None

    1981-01-01

    The area of accelerator mass spectrometry has expanded considerably over the past few years and established itself as an independent and interdisciplinary research field. Three years have passed since the first meeting was held at Rochester. A Symposium on Accelerator Mass Spectrometry was held at Argonne on May 11-13, 1981. In attendance were 96 scientists of whom 26 were from outside the United States. The present proceedings document the program and excitement of the field. Papers are arranged according to the original program. A few papers not presented at the meeting have been added to complete the information on the status of accelerator mass spectrometry. Individual papers were prepared separately for the data base.

  16. Symposium on accelerator mass spectrometry

    International Nuclear Information System (INIS)

    The area of accelerator mass spectrometry has expanded considerably over the past few years and established itself as an independent and interdisciplinary research field. Three years have passed since the first meeting was held at Rochester. A Symposium on Accelerator Mass Spectrometry was held at Argonne on May 11-13, 1981. In attendance were 96 scientists of whom 26 were from outside the United States. The present proceedings document the program and excitement of the field. Papers are arranged according to the original program. A few papers not presented at the meeting have been added to complete the information on the status of accelerator mass spectrometry. Individual papers were prepared separately for the data base

  17. Mass spectrometry for biomarker development

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Chaochao; Liu, Tao; Baker, Erin Shammel; Rodland, Karin D.; Smith, Richard D.

    2015-06-19

    Biomarkers potentially play a crucial role in early disease diagnosis, prognosis and targeted therapy. In the past decade, mass spectrometry based proteomics has become increasingly important in biomarker development due to large advances in technology and associated methods. This chapter mainly focuses on the application of broad (e.g. shotgun) proteomics in biomarker discovery and the utility of targeted proteomics in biomarker verification and validation. A range of mass spectrometry methodologies are discussed emphasizing their efficacy in the different stages in biomarker development, with a particular emphasis on blood biomarker development.

  18. Cluster secondary ion mass spectrometry microscope mode mass spectrometry imaging

    NARCIS (Netherlands)

    Kiss, A.; Smith, D.F.; Jungmann, JH; Heeren, R.M.A.

    2013-01-01

    RATIONALE: Microscope mode imaging for secondary ion mass spectrometry is a technique with the promise of simultaneous high spatial resolution and high-speed imaging of biomolecules from complex surfaces. Technological developments such as new position-sensitive detectors, in combination with polyat

  19. A mass spectrometry primer for mass spectrometry imaging.

    Science.gov (United States)

    Rubakhin, Stanislav S; Sweedler, Jonathan V

    2010-01-01

    Mass spectrometry imaging (MSI), a rapidly growing subfield of chemical imaging, employs mass spectrometry (MS) technologies to create single- and multi-dimensional localization maps for a variety of atoms and molecules. Complimentary to other imaging approaches, MSI provides high chemical specificity and broad analyte coverage. This powerful analytical toolset is capable of measuring the distribution of many classes of inorganics, metabolites, proteins, and pharmaceuticals in chemically and structurally complex biological specimens in vivo, in vitro, and in situ. The MSI approaches highlighted in this Methods in Molecular Biology volume provide flexibility of detection, characterization, and identification of multiple known and unknown analytes. The goal of this chapter is to introduce investigators who may be unfamiliar with MS to the basic principles of the mass spectrometric approaches as used in MSI. In addition to guidelines for choosing the most suitable MSI method for specific investigations, cross-references are provided to the chapters in this volume that describe the appropriate experimental protocols.

  20. New insights into PM2.5 chemical composition and sources in two major cities in China during extreme haze events using aerosol mass spectrometry

    Science.gov (United States)

    Elser, Miriam; Huang, Ru-Jin; Wolf, Robert; Slowik, Jay G.; Wang, Qiyuan; Canonaco, Francesco; Li, Guohui; Bozzetti, Carlo; Daellenbach, Kaspar R.; Huang, Yu; Zhang, Renjian; Li, Zhengqiang; Cao, Junji; Baltensperger, Urs; El-Haddad, Imad; Prévôt, André S. H.

    2016-03-01

    During winter 2013-2014 aerosol mass spectrometer (AMS) measurements were conducted for the first time with a novel PM2.5 (particulate matter with aerodynamic diameter ≤ 2.5 µm) lens in two major cities of China: Xi'an and Beijing. We denote the periods with visibility below 2 km as extreme haze and refer to the rest as reference periods. During the measurements in Xi'an an extreme haze covered the city for about a week and the total non-refractory (NR)-PM2.5 mass fraction reached peak concentrations of over 1000 µg m-3. During the measurements in Beijing two extreme haze events occurred, but the temporal extent and the total concentrations reached during these events were lower than in Xi'an. Average PM2.5 concentrations of 537 ± 146 and 243 ± 47 µg m-3 (including NR species and equivalent black carbon, eBC) were recorded during the extreme haze events in Xi'an and Beijing, respectively. During the reference periods the measured average concentrations were 140 ± 99 µg m-3 in Xi'an and 75 ± 61 µg m-3 in Beijing. The relative composition of the NR-PM2.5 evolved substantially during the extreme haze periods, with increased contributions of the inorganic components (mostly sulfate and nitrate). Our results suggest that the high relative humidity present during the extreme haze events had a strong effect on the increase of sulfate mass (via aqueous phase oxidation of sulfur dioxide). Another relevant characteristic of the extreme haze is the size of the measured particles. During the extreme haze events, the AMS showed much larger particles, with a volume weighted mode at about 800 to 1000 nm, in contrast to about 400 nm during reference periods. These large particle sizes made the use of the PM2.5 inlet crucial, especially during the severe haze events, where 39 ± 5 % of the mass would have been lost in the conventional PM1 (particulate matter with aerodynamic diameter ≤ 1 µm) inlet. A novel positive matrix factorization procedure was developed to

  1. Mass Spectrometry Instrumentation in Proteomics

    DEFF Research Database (Denmark)

    Sprenger, Richard Remko; Roepstorff, Peter

    2012-01-01

    Mass spectrometry has evolved into a crucial technology for the field of proteomics, enabling the comprehensive study of proteins in biological systems. Innovative developments have yielded flexible and versatile mass spectrometric tools, including quadrupole time-of-flight, linear ion trap, Orbi....... In terms of desired outcome, cost and time, combining and choosing between available instrumentation and methodologies is key to find the best analytical strategy suiting a particular proteomics experiment....

  2. Resonance ionisation mass spectrometry

    International Nuclear Information System (INIS)

    This report presents the results of an investigation of the technique resonance ionization mass spectroscopy. It offers the possibility of quick, accurate and highly sensitive analysis of samples which have undergone a minimum of chemical pretreatment. The technique can be applied to the detection of elements in trace amounts and for the detection of isotopes. Sample preparation, low-level counting and instrumentation are discussed. The proven capabilities and limitations of the technique and its commercial application and potential are presented. (U.K.)

  3. Mass Spectrometry in Polymer Chemistry

    CERN Document Server

    Barner-Kowollik, Christopher; Falkenhagen, Jana; Weidner, Steffen

    2011-01-01

    Combining an up-to-date insight into mass-spectrometric polymer analysis beyond MALDI with application details of the instrumentation, this is a balanced and thorough presentation of the most important and widely used mass-spectrometric methods.Written by the world's most proficient experts in the field, the book focuses on the latest developments, covering such technologies and applications as ionization protocols, tandem and liquid chromatography mass spectrometry, gas-phase ion-separation techniques and automated data processing. Chapters on sample preparation, polymer degradation and the u

  4. Contribution of methane to aerosol carbon mass

    Science.gov (United States)

    Bianchi, F.; Barmet, P.; Stirnweis, L.; El Haddad, I.; Platt, S. M.; Saurer, M.; Lötscher, C.; Siegwolf, R.; Bigi, A.; Hoyle, C. R.; DeCarlo, P. F.; Slowik, J. G.; Prévôt, A. S. H.; Baltensperger, U.; Dommen, J.

    2016-09-01

    Small volatile organic compounds (VOC) such as methane (CH4) have long been considered non-relevant to aerosol formation due to the high volatility of their oxidation products. However, even low aerosol yields from CH4, the most abundant VOC in the atmosphere, would contribute significantly to the total particulate carbon budget. In this study, organic aerosol (OA) mass yields from CH4 oxidation were evaluated at the Paul Scherrer Institute (PSI) smog chamber in the presence of inorganic and organic seed aerosols. Using labeled 13C methane, we could detect its oxidation products in the aerosol phase, with yields up to 0.09

  5. Real-time analysis of organic compounds in ship engine aerosol emissions using resonance-enhanced multiphoton ionisation and proton transfer mass spectrometry.

    Science.gov (United States)

    Radischat, Christian; Sippula, Olli; Stengel, Benjamin; Klingbeil, Sophie; Sklorz, Martin; Rabe, Rom; Streibel, Thorsten; Harndorf, Horst; Zimmermann, Ralf

    2015-08-01

    Organic combustion aerosols from a marine medium-speed diesel engine, capable to run on distillate (diesel fuel) and residual fuels (heavy fuel oil), were investigated under various operating conditions and engine parameters. The online chemical characterisation of the organic components was conducted using a resonance-enhanced multiphoton ionisation time-of-flight mass spectrometer (REMPI TOF MS) and a proton transfer reaction-quadrupole mass spectrometer (PTR-QMS). Oxygenated species, alkenes and aromatic hydrocarbons were characterised. Especially the aromatic hydrocarbons and their alkylated derivatives were very prominent in the exhaust of both fuels. Emission factors of known health-hazardous compounds (e.g. mono- and poly-aromatic hydrocarbons) were calculated and found in higher amounts for heavy fuel oil (HFO) at typical engine loadings. Lower engine loads lead in general to increasing emissions for both fuels for almost every compound, e.g. naphthalene emissions varied for diesel fuel exhaust between 0.7 mg/kWh (75 % engine load, late start of injection (SOI)) and 11.8 mg/kWh (10 % engine load, late SOI) and for HFO exhaust between 3.3 and 60.5 mg/kWh, respectively. Both used mass spectrometric techniques showed that they are particularly suitable methods for online monitoring of combustion compounds and very helpful for the characterisation of health-relevant substances. Graphical abstract Three-dimensional REMPI data of organic species in diesel fuel and heavy fuel oil exhaust. PMID:25600686

  6. Molecular Characterization of S- and N-containing Organic Constituents in Ambient Aerosols by negative ion mode High-Resolution Nanospray Desorption Electrospray Ionization Mass Spectrometry: CalNex 2010 field study

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Rachel E.; Laskin, Alexander; Laskin, Julia; Rubitschun, Caitlin L.; Surratt, Jason D.; Goldstein, Allen H.

    2014-11-27

    Samples of ambient aerosols from the 2010 California Research at the Nexus of Air Quality and Climate Change (CalNex) field study were analyzed using Nanospray Desorption Electrospray Ionization High Resolution Mass Spectrometry (nano-DESI/MS). Four samples per day were collected in Bakersfield, CA on June 20-24 with a collection time of 6 hours per sample. Four characteristic groups of organic constituents were identified in the samples: compounds containing carbon, hydrogen, and oxygen only (CHO), sulfur- (CHOS), nitrogen-(CHON), and both nitrogen- and sulfur-containing organics (CHONS). Within the groups, organonitrates, organosulfates, and nitroxy organosulfates were assigned based on accurate mass measurements and elemental ratio comparisons. Changes in the chemical composition of the aerosol samples were observed throughout the day. The number of observed CHO compounds increased in the afternoon samples, suggesting regional photochemical processing as a source. The average number of CHOS compounds had the smallest changes throughout the day, consistent with a more broadly distributed source. Both of the nitrogen-containing groups (CHON and CHONS) had greater numbers of compounds in the night and morning samples, indicating that nitrate radical chemistry was likely a source for those compounds. Most of the compounds were found in submicron particles. The size distribution of CHON compounds was bimodal. We conclude that the majority of the compounds observed were secondary in nature with both biogenic and anthropogenic sources.

  7. Open Mass Spectrometry Search Algorithm

    CERN Document Server

    Geer, L Y; Kowalak, J A; Wagner, L; Xu, M; Maynard, D M; Yang, X; Shi, W; Bryant, S H; Geer, Lewis Y.; Markey, Sanford P.; Kowalak, Jeffrey A.; Wagner, Lukas; Xu, Ming; Maynard, Dawn M.; Yang, Xiaoyu; Shi, Wenyao; Bryant, Stephen H.

    2004-01-01

    Large numbers of MS/MS peptide spectra generated in proteomics experiments require efficient, sensitive and specific algorithms for peptide identification. In the Open Mass Spectrometry Search Algorithm [OMSSA], specificity is calculated by a classic probability score using an explicit model for matching experimental spectra to sequences. At default thresholds, OMSSA matches more spectra from a standard protein cocktail than a comparable algorithm. OMSSA is designed to be faster than published algorithms in searching large MS/MS datasets.

  8. Laser sputter neutral mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    King, B.V.; Clarke, M.; Hu, H.; Betz [Newcastle Univ., NSW (Australia). Dept. of Physics

    1993-12-31

    Laser sputter neutral mass spectrometry (LSNMS) is an emerging technique for highly sensitive surface analysis. In this technique a target is bombarded with a pulsed beam of keV ions. The sputtered particles are intercepted by a high intensity pulsed laser beam above the surface and ionised with almost 100% efficiency. The photions may then be mass analysed using a quadrupole or, more commonly, using time of flight (TOF) techniques. In this method photoions are extracted from the ionisation region, accelerated to a known energy E{sub o} and strike a channelplate detector a distance `d` away. The flight time `t` of the photoions is then related to their mass by `d` {radical}m / {radical} 2E{sub o} so measurement of `t` allows mass spectra to be obtained. It is found that LSNMS is an emerging technique of great sensitivity and flexibility, useful for both applied analysis and to investigate basic sputtering processes. 4 refs., 3 figs.

  9. Quantitative mass spectrometry: an overview

    Science.gov (United States)

    Urban, Pawel L.

    2016-10-01

    Mass spectrometry (MS) is a mainstream chemical analysis technique in the twenty-first century. It has contributed to numerous discoveries in chemistry, physics and biochemistry. Hundreds of research laboratories scattered all over the world use MS every day to investigate fundamental phenomena on the molecular level. MS is also widely used by industry-especially in drug discovery, quality control and food safety protocols. In some cases, mass spectrometers are indispensable and irreplaceable by any other metrological tools. The uniqueness of MS is due to the fact that it enables direct identification of molecules based on the mass-to-charge ratios as well as fragmentation patterns. Thus, for several decades now, MS has been used in qualitative chemical analysis. To address the pressing need for quantitative molecular measurements, a number of laboratories focused on technological and methodological improvements that could render MS a fully quantitative metrological platform. In this theme issue, the experts working for some of those laboratories share their knowledge and enthusiasm about quantitative MS. I hope this theme issue will benefit readers, and foster fundamental and applied research based on quantitative MS measurements. This article is part of the themed issue 'Quantitative mass spectrometry'.

  10. Quantitative mass spectrometry: an overview.

    Science.gov (United States)

    Urban, Pawel L

    2016-10-28

    Mass spectrometry (MS) is a mainstream chemical analysis technique in the twenty-first century. It has contributed to numerous discoveries in chemistry, physics and biochemistry. Hundreds of research laboratories scattered all over the world use MS every day to investigate fundamental phenomena on the molecular level. MS is also widely used by industry-especially in drug discovery, quality control and food safety protocols. In some cases, mass spectrometers are indispensable and irreplaceable by any other metrological tools. The uniqueness of MS is due to the fact that it enables direct identification of molecules based on the mass-to-charge ratios as well as fragmentation patterns. Thus, for several decades now, MS has been used in qualitative chemical analysis. To address the pressing need for quantitative molecular measurements, a number of laboratories focused on technological and methodological improvements that could render MS a fully quantitative metrological platform. In this theme issue, the experts working for some of those laboratories share their knowledge and enthusiasm about quantitative MS. I hope this theme issue will benefit readers, and foster fundamental and applied research based on quantitative MS measurements.This article is part of the themed issue 'Quantitative mass spectrometry'.

  11. Quantitative mass spectrometry: an overview.

    Science.gov (United States)

    Urban, Pawel L

    2016-10-28

    Mass spectrometry (MS) is a mainstream chemical analysis technique in the twenty-first century. It has contributed to numerous discoveries in chemistry, physics and biochemistry. Hundreds of research laboratories scattered all over the world use MS every day to investigate fundamental phenomena on the molecular level. MS is also widely used by industry-especially in drug discovery, quality control and food safety protocols. In some cases, mass spectrometers are indispensable and irreplaceable by any other metrological tools. The uniqueness of MS is due to the fact that it enables direct identification of molecules based on the mass-to-charge ratios as well as fragmentation patterns. Thus, for several decades now, MS has been used in qualitative chemical analysis. To address the pressing need for quantitative molecular measurements, a number of laboratories focused on technological and methodological improvements that could render MS a fully quantitative metrological platform. In this theme issue, the experts working for some of those laboratories share their knowledge and enthusiasm about quantitative MS. I hope this theme issue will benefit readers, and foster fundamental and applied research based on quantitative MS measurements.This article is part of the themed issue 'Quantitative mass spectrometry'. PMID:27644965

  12. Online determination of levoglucosan in ambient aerosols with Particle-into-Liquid Sampler – High-Performance Anion-Exchange Chromatography – Mass Spectrometry (PILS–HPAEC–MS

    Directory of Open Access Journals (Sweden)

    K. Saarnio

    2013-06-01

    Full Text Available Biomass burning, such as domestic heating, agricultural, and wild open-land fires, has a significant influence on the atmosphere at the global and, especially, at the local scale. Levoglucosan has been shown to be a good tracer for biomass burning emissions in atmospheric particulate matter and several analytical techniques have been presented for the determination of levoglucosan from filter samples. In this paper, a novel combination of a Particle-into-Liquid Sampler (PILS to a high-performance anion-exchange chromatograph (HPAEC with the detection by a mass spectrometer (MS is presented for the online analysis of levoglucosan in ambient particles. The PILS–HPAEC–MS technique enables a fast online analysis of levoglucosan from the particulate samples. The method was tested at an urban background station in Helsinki, Finland, in winter 2011. A comparison with simultaneous levoglucosan measurements from filter samples by the HPAEC–MS was performed and it showed a good agreement between the online and offline methods. Additionally, the online levoglucosan data were compared with the biomass burning tracer fragments measured by a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS. As there were no local biomass burning sources close to the measurement station, online levoglucosan measurements revealed that most of the particles from biomass burning were either regionally distributed or long-range transported in the urban background of Helsinki. The average levoglucosan concentrations were relatively low (average 0.083 μg m−3 during the measurement campaign. The highest concentration peak measured for levoglucosan (1.4 μg m−3 seemed to originate from biomass burning in Eastern Europe, likely in Estonia, that was transported to Helsinki.

  13. Online determination of levoglucosan in ambient aerosols with particle-into-liquid sampler – high-performance anion-exchange chromatography – mass spectrometry (PILS–HPAEC–MS

    Directory of Open Access Journals (Sweden)

    K. Saarnio

    2013-10-01

    Full Text Available Biomass burning, such as domestic heating, agricultural, and wild open-land fires, has a significant influence on the atmosphere at the global and, especially, at the local scale. Levoglucosan has been shown to be a good tracer for biomass burning emissions in atmospheric particulate matter, and several analytical techniques have been presented for the determination of levoglucosan from filter samples. In this paper, a novel combination of a particle-into-liquid sampler (PILS to a high-performance anion-exchange chromatograph (HPAEC with the detection by a mass spectrometer (MS is presented for the online analysis of levoglucosan in ambient particles. The PILS–HPAEC–MS technique enables a fast online analysis of levoglucosan from the particulate samples. The method was tested at an urban background station in Helsinki, Finland, in winter 2011. A comparison with simultaneous levoglucosan measurements from filter samples by the HPAEC–MS was performed and it showed a good agreement between the online and offline methods. Additionally, the online levoglucosan data were compared with the biomass burning tracer fragments measured by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS. As there were no local biomass burning sources close to the measurement station, online levoglucosan measurements revealed that most of the particles from biomass burning were either regionally distributed or long-range transported in the urban background of Helsinki. The average levoglucosan concentrations were relatively low (average 0.083 μg m−3 during the measurement campaign. The highest concentration peak measured for levoglucosan (1.4 μg m−3 seemed to originate from biomass burning in the Baltic countries, likely in Estonia, that was transported to Helsinki.

  14. Online determination of levoglucosan in ambient aerosols with particle-into-liquid sampler - high-performance anion-exchange chromatography - mass spectrometry (PILS-HPAEC-MS)

    Science.gov (United States)

    Saarnio, K.; Teinilä, K.; Saarikoski, S.; Carbone, S.; Gilardoni, S.; Timonen, H.; Aurela, M.; Hillamo, R.

    2013-10-01

    Biomass burning, such as domestic heating, agricultural, and wild open-land fires, has a significant influence on the atmosphere at the global and, especially, at the local scale. Levoglucosan has been shown to be a good tracer for biomass burning emissions in atmospheric particulate matter, and several analytical techniques have been presented for the determination of levoglucosan from filter samples. In this paper, a novel combination of a particle-into-liquid sampler (PILS) to a high-performance anion-exchange chromatograph (HPAEC) with the detection by a mass spectrometer (MS) is presented for the online analysis of levoglucosan in ambient particles. The PILS-HPAEC-MS technique enables a fast online analysis of levoglucosan from the particulate samples. The method was tested at an urban background station in Helsinki, Finland, in winter 2011. A comparison with simultaneous levoglucosan measurements from filter samples by the HPAEC-MS was performed and it showed a good agreement between the online and offline methods. Additionally, the online levoglucosan data were compared with the biomass burning tracer fragments measured by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). As there were no local biomass burning sources close to the measurement station, online levoglucosan measurements revealed that most of the particles from biomass burning were either regionally distributed or long-range transported in the urban background of Helsinki. The average levoglucosan concentrations were relatively low (average 0.083 μg m-3) during the measurement campaign. The highest concentration peak measured for levoglucosan (1.4 μg m-3) seemed to originate from biomass burning in the Baltic countries, likely in Estonia, that was transported to Helsinki.

  15. Electrophoresis-mass spectrometry probe

    Science.gov (United States)

    Andresen, Brian D.; Fought, Eric R.

    1987-01-01

    The invention involves a new technique for the separation of complex mixtures of chemicals, which utilizes a unique interface probe for conventional mass spectrometers which allows the electrophoretically separated compounds to be analyzed in real-time by a mass spectrometer. This new chemical analysis interface, which couples electrophoresis with mass spectrometry, allows complex mixtures to be analyzed very rapidly, with much greater specificity, and with greater sensitivity. The interface or probe provides a means whereby large and/or polar molecules in complex mixtures to be completely characterized. The preferred embodiment of the probe utilizes a double capillary tip which allows the probe tip to be continually wetted by the buffer, which provides for increased heat dissipation, and results in a continually operating interface which is more durable and electronically stable than the illustrated single capillary tip probe interface.

  16. Following the Biochemical and Morphological Changes of Bacillus atrophaeus during Sporulation using Bioaerosol Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tobias, H J; Pitesky, M E; Fergenson, D P; Horn, J; Frank, M; Gard, E E

    2006-05-03

    The overall objective of this report is to develop a real-time single-particle mass spectrometry technique called Bio-Aerosol Mass Spectrometry (BAMS) in order to efficiently screen and identify bioaerosols and single cells of national security and public health concern.

  17. Mexico City Aerosol Analysis during MILAGRO using High Resolution Aerosol Mass Spectrometry at the Urban Supersite (T0). Part 2: Analysis of the Biomass Burning Contribution and the Modern Carbon Fraction

    Energy Technology Data Exchange (ETDEWEB)

    Aiken, Allison; de Foy, B.; Wiedinmyer, Christine; DeCarlo, Peter; Ulbrich, Ingrid M.; Wehrli, M. N.; Szidat, S.; Prevot, A. S. H.; Noda, J.; Wacker, L.; Volkamer, Rainer M.; Fortner, Edward; Wang, J. X.; Laskin, Alexander; Shutthanandan, V.; Zheng, J.; Zhang, Renyi; Paredes-Miranda, Guadalupe L.; Arnott, W. P.; Molina, Luis; Sosa, G.; Querol, X.; Jimenez, J. L.

    2010-06-16

    Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Aerosol Mass Spectrometer (AMS) and complementary instrumentation. Positive Matrix Factorization (PMF) of high resolution AMS spectra identified a biomass burning OA (BBOA) component, which includes several large plumes that appear to be from forest fires within the region. Here, we show that the AMS BBOA concentration at T0 correlates with fire counts in the vicinity of Mexico City and that most of the BBOA variability is captured when the FLEXPART model is used for the dispersion of fire emissions as estimated from satellite fire counts. The resulting FLEXPART fire impact index correlates well with the observed BBOA, CH3CN, levoglucosan, and potassium, indicating that wildfires in the region surrounding Mexico City are the dominant source of BBOA at T0 during MILAGRO. The impact of distant BB sources such as the Yucatan is very small during this period. All fire tracers are correlated, with BBOA and levoglucosan showing little background, acetonitrile having a well-known tropospheric background of ~100-150 ppt, and PM2.5 potassium having a background of ~160 ng m-3 (two-thirds of its average concentration), which does not appear to be related to BB sources.

  18. Aerosols in King George Island (Antarctic peninsula) using PIXE and alpha spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dias da Cunha, K.; Medeiros, G., E-mail: kenya@ird.gov.b, E-mail: kenya@vdg.fis.puc-rio.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Leal, M.A.; Lima, C. [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Dalia, K.C. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Centro de Ciencias da Saude; Barros Leite, C.V. [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), Rio de Janeiro, RJ (Brazil)

    2009-07-01

    The aim of this study was to characterize the airborne particles and particles deposited in the recent snow samples collected at King George Island (Admiralty Bay) in order to evaluate the possible local sources of airborne particles and the aerosol transport from South America to Antarctic at sea level. Airborne particles samples were collected using a cascade impactor and cyclones at several sampling points at Admiralty Bay. Airborne particles were also collected during the ship travel from Rio de Janeiro to Antarctica. The recent snow samples and aerosols collected at several sampling points at Admiralty Bay were analyzed by PIXE for the determination of the elemental mass concentration. Snow samples were analyzed by alpha spectrometry to determine the 232Th, 228Th, 238U and 234U concentrations in snow. The Mass Median Aerodynamic Diameter of airborne particles was determined. The results suggest that there is a correlation between the aerosol samples and the particles deposited in the snow, but the elemental mass distributions are not equal. The snow elemental concentration can be used as an indicator of the elements present in the aerosols. The local aerosol sources (natural and anthropogenic) have been considered to characterize the aerosol transport to Antarctic, mainly King George Island. The main aerosol sources are the marine spray, weathering of local rocks and anthropogenic sources, as the diesel burning in the island. Besides the local aerosol sources the transport of airborne particles from south Atlantic to Antarctic is an important source of airborne particles at King George Island. (author)

  19. Protein Analysis by Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Cindic, M.

    2008-04-01

    Full Text Available Soft ionization techniques, electrospray (ESI and matrix-assisted laser desorption/ionization (MALDI make the analysis of biomolecules by mass spectrometry (MS possible. MS is used for determination of the molecular weight of peptides and protein, sequence analysis, characterization of protein-ligand interactions etc. The detection limit, resolution and mass accuracy depend on instrument used (Table 1. Impurities (buffers, salts, detergents can reduce the ion intensities or even totally suppress them, so a separation method (chromatography, 2D-gel electrophoresis must be used for purification of the sample.Molecular mass of intact protein can be determined by ESI or MALDI MS. Multiply charged ions are produced by ESI MS, while singly charged ions are predominant in MALDI spectra (Fig. 2.Sequence analysis of proteins by MS can be performed using peptide mass fingerprint. In this method, proteins are separated by 2-D gel electrophoresis and digested with specific protease (Table 2 or digested and then separated by two-dimensional chromatography (Fig. 1. The obtained peptide mixtures are analyzed by MS or MALDI-TOF technique. The masses determined by MS are compared with calculated masses from database entries. Different algorithms have been developed for protein identification. Example of posttranslational modifications (N- and O-glycosylation and protein sequence complex analysis after dual digestion (endoproteinase digestion followed by endoglycosidase digestion is shown in Fig. 3.It is known that detection of peptides by MS is influenced by intrinsic properties like amino acid composition, the basicity of the C-terminal amino acid, hydrophobicity, etc. Arginine-containing peptides dominate in MS spectra of tryptic digest, so the chemical derivatization of lysine terminal residue by O-methilisourea or 2-methoxy-4,5-1H-imidazole was suggested (Fig. 4.The peptide mass fingerprint method can be improved further by peptide fragmentation using tandem

  20. Microwave-assisted Extraction of Rare Earth Elements from Petroleum Refining Catalysts and Ambient Fine Aerosols Prior to Inductively Coupled Plasma - Mass Spectrometry

    Science.gov (United States)

    Mittlefehldt, David W.; Kulkarni, Pranav; Chellam, Shankar

    2006-01-01

    In the absence of a certified reference material, a robust microwave-assisted acid digestion procedure followed by inductively coupled plasma - mass spectrometry (ICP-MS) was developed to quantify rare earth elements (REEs) in fluidized-bed catalytic cracking (FCC) catalysts and atmospheric fine particulate matter (PM2.5). High temperature (200 C), high pressure (200 psig), acid digestion (HNO3, HF, and H3BO3) with 20 minute dwell time effectively solubilized REEs from six fresh catalysts, a spent catalyst, and PM2.5. This method was also employed to measure 27 non-REEs including Na, Mg, Al, Si, K, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Zr, Mo, Cd, Cs, Ba, Pb, and U. Complete extraction of several REEs (Y, La, Ce, Pr, Nd, Tb, Dy, and Er) required HF indicating that they were closely associated with the aluminosilicate structure of the zeolite FCC catalysts. Internal standardization using 115In quantitatively corrected non-spectral interferences in the catalyst digestate matrix. Inter-laboratory comparison using ICP-optical emission spectroscopy (ICP-OES) and instrumental neutron activation analysis (INAA) demonstrated the applicability of the newly developed analytical method for accurate analysis of REEs in FCC catalysts. The method developed for FCC catalysts was also successfully implemented to measure trace to ultra-trace concentrations of La, Ce, Pr, Nd, Sm, Gd, Eu, and Dy in ambient PM2.5 in an industrial area of Houston, TX.

  1. Characterization of ambient aerosols in Mexico City during the MCMA-2003 campaign with Aerosol Mass Spectrometry – Part II: overview of the results at the CENICA supersite and comparison to previous studies

    Directory of Open Access Journals (Sweden)

    D. Salcedo

    2005-06-01

    Full Text Available An Aerodyne Aerosol Mass Spectrometer (AMS was deployed at the CENICA Supersite during the Mexico City Metropolitan Area field study from 31 March–4 May 2003. The AMS provides real time information on mass concentration and composition of the non-refractory species in particulate matter less than 1 µm (NR-PM1 with high time and size-resolution. Measurements of Black Carbon (BC using an aethalometer, and estimated soil concentrations from Proton-Induced X-Ray Emission (PIXE analysis of impactor substrates are also presented and combined with the AMS in order to include refractory material and estimate the total PM2.5 mass concentration at CENICA during this campaign. In Mexico City, the organic fraction of the estimated PM2.5 at CENICA represents 54.6% of the mass, with the rest consisting of inorganic compounds (mainly ammonium nitrate and sulfate/ammonium salts, BC, and soil. Inorganic compounds represent 27.5% of PM2.5; BC mass concentration is about 11%; while soil represents about 6.9%. The NR species and BC have diurnal cycles that can be qualitatively interpreted as the interplay of direct emissions, photochemical production in the atmosphere followed by condensation and gas-to-particle partitioning, boundary layer dynamics, and/or advection. Bi- and trimodal size distributions are observed for the AMS species, with a small combustion (likely traffic organic particle mode and an accumulation mode that contains mainly organic and secondary inorganic compounds. The AMS and BC mass concentrations, size distributions, and diurnal cycles are found to be qualitatively similar to those from most previous field measurements in Mexico City.

  2. Neuroscience and Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Palmblad, M N; Buchholz, B A; Hillegonds, D J; Vogel, J S

    2004-08-02

    Accelerator mass spectrometry (AMS) is a mass spectrometric method for quantifying rare isotopes. It has had great impact in geochronology and archaeology and is now being applied in biomedicine. AMS measures radioisotopes such as {sup 3}H, {sup 14}C, {sup 26}Al, {sup 36}Cl and {sup 41}Ca, with zepto- or attomole sensitivity and high precision and throughput, enabling safe human pharmacokinetic studies involving: microgram doses, agents having low bioavailability, or toxicology studies where administered doses must be kept low (<1 {micro}g/kg). It is used to study long-term pharmacokinetics, to identify biomolecular interactions, to determine chronic and low-dose effects or molecular targets of neurotoxic substances, to quantify transport across the blood-brain barrier and to resolve molecular turnover rates in the human brain on the timescale of decades. We will here review how AMS is applied in neurotoxicology and neuroscience.

  3. The life sciences mass spectrometry research unit.

    Science.gov (United States)

    Hopfgartner, Gérard; Varesio, Emmanuel

    2012-01-01

    The Life Sciences Mass Spectrometry (LSMS) research unit focuses on the development of novel analytical workflows based on innovative mass spectrometric and software tools for the analysis of low molecular weight compounds, peptides and proteins in complex biological matrices. The present article summarizes some of the recent work of the unit: i) the application of matrix-assisted laser desorption/ionization (MALDI) for mass spectrometry imaging (MSI) of drug of abuse in hair, ii) the use of high resolution mass spectrometry for simultaneous qualitative/quantitative analysis in drug metabolism and metabolomics, and iii) the absolute quantitation of proteins by mass spectrometry using the selected reaction monitoring mode. PMID:22867547

  4. Molecular characterization of S- and N-containing organic constituents in ambient aerosols by negative ion mode high-resolution Nanospray Desorption Electrospray Ionization Mass Spectrometry: CalNex 2010 field study

    Science.gov (United States)

    O'Brien, Rachel E.; Laskin, Alexander; Laskin, Julia; Rubitschun, Caitlin L.; Surratt, Jason D.; Goldstein, Allen H.

    2014-11-01

    Samples of ambient aerosols from the 2010 California Research at the Nexus of Air Quality and Climate Change (CalNex) field study were analyzed using negative ion mode Nanospray Desorption Electrospray Ionization High-Resolution Mass Spectrometry (nano-DESI/MS). Four samples per day (6 h each) were collected in Bakersfield, CA on 20-24 June. Four characteristic groups were identified: molecules composed of carbon, hydrogen, and oxygen only (CHO), sulfur- (CHOS), nitrogen- (CHON), and both nitrogen- and sulfur-containing organics (CHONS). The chemical formula and elemental ratios were consistent with the presence of organonitrates, organosulfate, and nitroxy organosulfates in the negative ion mode mass spectra. The number of observed CHO compounds increased in the afternoon samples, suggesting photochemical processing as a source. The average number of CHOS compounds had the smallest changes during the day, consistent with a more broadly distributed source. Both of the nitrogen-containing groups (CHONS and CHON) had greater numbers of compounds in the early morning (midnight to 6 A.M.) and night (6 P.M. to midnight) samples, respectively, consistent with nitrate radical chemistry as a likely source for those compounds. Most of the compounds were found in submicron particles. The size distribution of the number of CHON compounds was bimodal, potentially indicating two types of sources. We conclude that the majority of the compounds observed were secondary in nature with both biogenic and anthropogenic sources. These data are complementary to previous results from positive ion mode nano-DESI/MS analysis of a subset of the same samples providing a more complete view of aerosol chemical composition at Bakersfield.

  5. Quantitative mass spectrometry: an overview

    Science.gov (United States)

    2016-01-01

    Mass spectrometry (MS) is a mainstream chemical analysis technique in the twenty-first century. It has contributed to numerous discoveries in chemistry, physics and biochemistry. Hundreds of research laboratories scattered all over the world use MS every day to investigate fundamental phenomena on the molecular level. MS is also widely used by industry—especially in drug discovery, quality control and food safety protocols. In some cases, mass spectrometers are indispensable and irreplaceable by any other metrological tools. The uniqueness of MS is due to the fact that it enables direct identification of molecules based on the mass-to-charge ratios as well as fragmentation patterns. Thus, for several decades now, MS has been used in qualitative chemical analysis. To address the pressing need for quantitative molecular measurements, a number of laboratories focused on technological and methodological improvements that could render MS a fully quantitative metrological platform. In this theme issue, the experts working for some of those laboratories share their knowledge and enthusiasm about quantitative MS. I hope this theme issue will benefit readers, and foster fundamental and applied research based on quantitative MS measurements. This article is part of the themed issue ‘Quantitative mass spectrometry’. PMID:27644965

  6. Hyphenation of a EC / OC thermal-optical carbon analyzer to photo ionization time-of-flight mass spectrometry: a new off-line aerosol mass spectrometric approach for characterization of primary and secondary particulate matter

    Directory of Open Access Journals (Sweden)

    J. Diab

    2015-01-01

    Full Text Available Source apportionment and exposure of primary and secondary aerosols remains a challenging research field. In particular, the organic composition of primary particles and the formation mechanism of secondary organic aerosols (SOA warrant further investigations. Progress in this field is strongly connected to the development of novel analytical techniques. In this study an off-line aerosol mass spectrometric technique based on filter samples, a hyphenated thermal/optical analyzer-photo ionization time of flight mass spectrometer (PI-TOFMS system, was developed. The approach extends the capability of the widely used PM carbon analysis (for elemental/organic carbon (EC / OC by enabling the investigation of evolved gaseous species with soft and selective (resonance enhanced multiphoton ionization, REMPI and non-selective photo ionization (single photon ionization, SPI techniques. SPI was tuned to be medium soft to achieve comparability with results obtained by electron ionization (EI aerosol mass spectrometer (AMS. Different PM samples including wood combustion emission samples, smog chamber samples from the reaction of ozone with different SOA precursors, and ambient samples taken at Ispra, Italy in winter as well as in summer were tested. The EC / OC-PI-TOFMS technique increases the understanding of the processes during the thermal/optical analysis and identifies marker substances for the source apportionment. Composition of oligomeric or polymeric species present in PM can be investigated by the analysis of the thermally breakdown products. In case of wood combustion, in addition to the well-known markers at m/z ratios of 60 and 73, two new characteristic masses (m/z 70 and 98 have been revealed as potentially linked to biomass burning. All four masses were also the dominant signals in an ambient sample taken in winter time in Ispra, Italy, confirming the finding that wood burning for residential heating is a major source for particulate matter

  7. Application of Lithium Attachment Mass Spectrometry for Knudsen Evaporation and Chemical Ionisation Mass Spectrometry (KEMS, CIMS)

    Science.gov (United States)

    Bannan, Thomas; Booth, A. Murray; Alfarra, Rami; Bacak, Asan; Pericval, Carl

    2016-04-01

    Lithium ion attachment mass spectrometry provides a non-specific, non-fragmenting and sensitive method for detection of volatile species in the gas phase. The design, manufacture, and results from lithium ion attachment ionisation sources for two mass spectrometry systems are presented. Trace gas analysis is investigated using a modified Chemical Ionization Mass Spectrometer (CIMS) and vapour pressure (VP) measurements using a modified Knudsen Effusion Mass Spectrometer (KEMS) are presented. The Li+ modified CIMS provided limits of detection of 4 ppt for acetone, 0.2 ppt for formic acid, 15 ppt for nitric acid and 120 ppt from ammonia. Despite improvements, the problem of burnout remained persistent. The Li+ CIMS would unlikely be suitable for field or aircraft work, but could be appropriate for certain lab applications. The KEMS currently utilizes an electron impact (EI) ionisation source which provides a highly sensitive source, with the drawback of fragmentation of ionized molecules (Booth et al., 2009). Using Li+ KEMS the VP of samples can be measured without fragmentation and can therefore be used to identify VPs of individual components in mixtures. The validity of using Li+ for determining the VP of mixtures was tested by making single component VP measurements, which showed good agreement with EI measurements of Poly ethylene glycol (PEG) 3 and PEG 4, both when individually measured and when mixed. The Li+ KEMS was then used to investigate a system of atmospheric relevance, α-pinene secondary organic aerosol, generated in a reaction chamber (Alfarra et al., 2012). The VPs of the individual components from this generated sample are within the range we expect for compounds capable of partitioning between the particle and gas phase of an aerosol (0.1-10-5 Pa). Li+ source has a calculated sensitivity approximately 75 times less than that of EI, but the lack of fragmentation using the Li+ source is a significant advantage.

  8. Mexico City aerosol analysis during MILAGRO using high resolution aerosol mass spectrometry at the urban supersite (T0 – Part 2: Analysis of the biomass burning contribution and the modern carbon fraction

    Directory of Open Access Journals (Sweden)

    J. L. Jimenez

    2009-12-01

    Full Text Available Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Aerosol Mass Spectrometer (AMS and complementary instrumentation. Positive Matrix Factorization (PMF of high resolution AMS spectra identified a biomass burning OA (BBOA component, which includes several large plumes that appear to be from forest fires within the region. Here, we show that the AMS BBOA concentration at T0 correlates with fire counts in the vicinity of Mexico City and that most of the BBOA variability is captured when the FLEXPART model is used for the dispersion of fire emissions as estimated from satellite fire counts. The resulting FLEXPART fire impact index correlates well with the observed BBOA, CH3CN, levoglucosan, and potassium, indicating that wildfires in the region surrounding Mexico City are the dominant source of BBOA at T0 during MILAGRO. The impact of distant BB sources such as the Yucatan is small during this period. All fire tracers are correlated, with BBOA and levoglucosan showing little background, acetonitrile having a well-known tropospheric background of ~100–150 ppt, and PM2.5 potassium having a background of ~160 ng m−3 (two-thirds of its average concentration, which does not appear to be related to BB sources. We define two high fire periods based on satellite fire counts and predicted fire impacts. We then compare these periods with a low fire period when the impact of regional fires is about a factor of 5 smaller. Fire tracers are very elevated in the high fire periods whereas tracers of urban pollution do not change between these periods. Dust is also elevated during the high BB period but this appears to be coincidental due to the drier conditions and not driven by direct dust emission from the fires. The AMS oxygenated OA factor (OOA, mostly secondary OA or SOA does not show an increase during the fire periods or a

  9. NICHD Biomedical Mass Spectrometry Core Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The NICHD Biomedical Mass Spectrometry Core Facility was created under the auspices of the Office of the Scientific Director to provide high-end mass-spectrometric...

  10. Mexico city aerosol analysis during MILAGRO using high resolution aerosol mass spectrometry at the urban supersite (T0) - Part 2: Analysis of the biomass burning contribution and the non-fossil carbon fraction

    Energy Technology Data Exchange (ETDEWEB)

    Aiken, A.C.; Wang, J.; de Foy, B.; Wiedinmyer, C.; DeCarlo, P. F.; Ulbrich, I. M.; Wehrli, M. N.; Szidat, S.; Prevot, A. S. H.; Noda, J.; Wacker, L.; Volkamer, R.; Fortner, E.; Laskin, A.; Shutthanandan, V.; Zheng, J.; Zhang, R.; Paredes-Miranda, G.; Arnott, W. P.; Molina, L. T.; Sosa, G.; Querol, X.; Jimenez, J. L.

    2010-06-16

    Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Aerosol Mass Spectrometer (AMS) and complementary instrumentation. Positive Matrix Factorization (PMF) of high resolution AMS spectra identified a biomass burning organic aerosol (BBOA) component, which includes several large plumes that appear to be from forest fires within the region. Here, we show that the AMS BBOA concentration at T0 correlates with fire counts in the vicinity of Mexico City and that most of the BBOA variability is captured when the FLEXPART model is used for the dispersion of fire emissions as estimated from satellite fire counts. The resulting FLEXPART fire impact factor (FIF) correlates well with the observed BBOA, acetonitrile (CH3CN), levoglucosan, and potassium, indicating that wildfires in the region surrounding Mexico City are the dominant source of BBOA at T0 during MILAGRO. The impact of distant BB sources such as the Yucatan is small during this period. All fire tracers are correlated, with BBOA and levoglucosan showing little background, acetonitrile having a well-known tropospheric background of {approx}100-150 pptv, and PM2.5 potassium having a background of {approx}160 ng m3 (two-thirds of its average concentration), which does not appear to be related to BB sources. We define two high fire periods based on satellite fire counts and FLEXPART-predicted FIFs. We then compare these periods with a low fire period when the impact of regional fires is about a factor of 5 smaller. Fire tracers are very elevated in the high fire periods whereas tracers of urban pollution do not change between these periods. Dust is also elevated during the high BB period but this appears to be coincidental due to the drier conditions and not driven by direct dust emission from the fires. The AMS oxygenated organic aerosol (OA) factor (OOA, mostly secondary OA or SOA) does not show an increase during the fire

  11. Proton transfer reaction - mass spectrometry

    International Nuclear Information System (INIS)

    Proton transfer reaction mass spectrometry (PTR-MS) provides on-line monitoring of volatile organic compounds (VOCs) with a low detection threshold and a fast response time. Commercially available set-ups are usually based on quadrupole analysers but recently new instruments based on time-of-flight (PTR-ToF-MS) analysers have been proposed and commercialized. PTR-MS has been successfully applied to a variety of fields including environmental science, food science and technology, plant physiology and medical science. Many new challenges arise from the newly available PTR-ToF-MS instruments, ranging from mass calibration and absolute VOC concentration determination to data mining and sample classification. This thesis addresses some of these problems in a coherent framework. Moreover, relevant applications in food science and technology are presented. It includes twelve papers published in peer reviewed journals. Some of them address methodological issues regarding PTR-ToF-MS; the others contain applicative studies of PTR-ToF-MS to food science and technology. Among them, there are the first two published applications of PTR-ToF-MS in this field. (author)

  12. Mass spectrometry-assisted protease substrate screening

    DEFF Research Database (Denmark)

    Schlüter, Hartmut; Rykl, Jana; Thiemann, Joachim;

    2007-01-01

    -phase chromatography they are analyzed by tandem mass spectrometry and the substrates identified by database searching. The proof of principle in this study is demonstrated by incubating immobilized human plasma proteins with thrombin and by identifying by tandem mass spectrometry the fibrinopeptides, released...

  13. Developments in ion mobility spectrometry-mass spectrometry.

    Science.gov (United States)

    Collins, D C; Lee, M L

    2002-01-01

    Ion mobility spectrometry (IMS) has been used for over 30 years as a sensitive detector of organic compounds. The following is a brief review of IMS and its principles with an emphasis on its usage when coupled to mass spectrometry. Since its inception, IMS has been interfaced with quadrupole, time-of-flight, and Fourier-transform ion cyclotron resonance mass spectrometry. These hybrid instruments have been employed for the analysis of a variety of target analytes, including biomolecules, explosives, chemical warfare degradation products, and illicit drugs. PMID:11939214

  14. Nonaqueous Capillary Electrophoresis Mass Spectrometry.

    Science.gov (United States)

    Klampfl, Christian W; Himmelsbach, Markus

    2016-01-01

    The term nonaqueous capillary electrophoresis (NACE) commonly refers to capillary electrophoresis with purely nonaqueous background electrolytes (BGE). Main advantages of NACE are the possibility to analyze substances with very low solubility in aqueous media as well as separation selectivity that can be quite different in organic solvents (compared to water)-a property that can be employed for manipulation of separation selectivities. Mass spectrometry (MS) has become more and more popular as a detector in CE a fact that applies also for NACE. In the present chapter, the development of NACE-MS since 2004 is reviewed. Relevant parameters like composition of BGE and its influence on separation and detection in NACE as well as sheath liquid for NACE-MS are discussed. Finally, an overview of the papers published in the field of NACE-MS between 2004 and 2014 is given. Applications are grouped according to the field (analysis of natural products, biomedical analysis, food analysis, analysis of industrial products, and fundamental investigations). PMID:27645734

  15. Absorption Mode FTICR Mass Spectrometry Imaging

    NARCIS (Netherlands)

    Smith, D.F.; Kilgour, D.P.A.; Konijnenburg, M.; O'Connor, P.B.; Heeren, R.M.A.

    2013-01-01

    Fourier transform ion cyclotron resonance mass spectrometry offers the highest mass resolving power for molecular imaging experiments. This high mass resolving power ensures that closely spaced peaks at the same nominal mass are resolved for proper image generation. Typically higher magnetic fields

  16. Use of mass spectrometry to study signaling pathways

    DEFF Research Database (Denmark)

    Pandey, A; Andersen, Jens S.; Mann, M

    2000-01-01

    identification by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry and nanoelectrospray tandem mass spectrometry. We discuss the special requirements for the identification of phosphorylation sites in proteins by mass spectrometry. We describe enrichment of phosphopeptides from unseparated...

  17. Methods for recalibration of mass spectrometry data

    Science.gov (United States)

    Tolmachev, Aleksey V.; Smith, Richard D.

    2009-03-03

    Disclosed are methods for recalibrating mass spectrometry data that provide improvement in both mass accuracy and precision by adjusting for experimental variance in parameters that have a substantial impact on mass measurement accuracy. Optimal coefficients are determined using correlated pairs of mass values compiled by matching sets of measured and putative mass values that minimize overall effective mass error and mass error spread. Coefficients are subsequently used to correct mass values for peaks detected in the measured dataset, providing recalibration thereof. Sub-ppm mass measurement accuracy has been demonstrated on a complex fungal proteome after recalibration, providing improved confidence for peptide identifications.

  18. Plasma Desorption Mass Spectrometry: Coming of Age.

    Science.gov (United States)

    Cotter, Robert J.

    1988-01-01

    Discusses the history and development of Plasma Desorption Mass Spectrometry to determine molecular weights and structures of proteins and polymers. Outlines theory, instrumentation, and sample preparation commonly used. Gives several examples of resulting spectra. (ML)

  19. Introduction to mass spectrometry-based proteomics

    DEFF Research Database (Denmark)

    Matthiesen, Rune; Bunkenborg, Jakob

    2013-01-01

    Mass spectrometry has been widely applied to study biomolecules and one rapidly developing field is the global analysis of proteins, proteomics. Understanding and handling mass spectrometry data is a multifaceted task that requires many decisions to be made to get the most comprehensive information...... from an experiment. Later chapters in this book deal in-depth with various aspects of the process and how different tools can be applied to the many analytical challenges. This introductory chapter is intended as a basic introduction to mass spectrometry (MS)-based proteomics to set the scene...... for newcomers and give pointers to reference material. There are many applications of mass spectrometry in proteomics and each application is associated with some analytical choices, instrumental limitations and data processing steps that depend on the aim of the study and means of conducting it. Different...

  20. Pyrolysis - gas chromatography - mass spectrometry of lignins

    Energy Technology Data Exchange (ETDEWEB)

    Martin, F.; Saiz-Jimenez, C.; Gonzalez-Vila, F.J.

    1979-01-01

    Milled wood lignins from spruce, beech and bamboo were pyrolysed. The high-boiling products of pyrolysis were studied by GLC and mass spectrometry. The forty-three products identified provide information on the structural units of lignin.

  1. Mass deposition from inspired polydisperse aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Rudolf, G.; Gebhart, J.; Heyder, J.; Scheuch, G.; Stahlhofen, W. (Gesellschaft fuer Strahlen- und Umweltforschung m.b.H., Frankfurt (Germany, F.R.). Inst. fuer Biophysikalische Strahlenforschung)

    1988-01-01

    Mass deposition of polydisperse hydrophobic aerosol particles in various regions of the human respiratory tract has been calculated using a semi-empirical deposition model and assuming lognormal particle size distributions. The effects of polydispersity, breathing mode (nose versus mouth breathing), breathing pattern, particle size and density upon mass deposition are discussed. Significant differences are found from the model predictions of the ICRP TASK GROUP ON LUNG DYNAMICS (1966) and later ICRP recommendations. The influence of the geometric standard deviation of the size distribution upon mass deposition depends on particle size, and a simple explanation of this effect is introduced. (author).

  2. Miniaturization of Mass Spectrometry Analysis Systems

    OpenAIRE

    Xu, Wei; Manicke, Nicholas E.; Cooks, Graham R.; Ouyang, Zheng

    2010-01-01

    The key concepts and technologies developed in our laboratories in Purdue University for the miniaturization of mass spectrometry analysis systems are introduced. Mass analyzers of simple geometries with a novel atmospheric pressure interface were employed allowed reduction in the size of the ion trap mass spectrometer. Ambient ionization methods were developed and coupled to miniature mass spectrometers to allow direct MS analysis of complex samples without sample preparation and chemical se...

  3. Analysis of mass spectrometry data in proteomics

    DEFF Research Database (Denmark)

    Matthiesen, Rune; Jensen, Ole N

    2008-01-01

    The systematic study of proteins and protein networks, that is, proteomics, calls for qualitative and quantitative analysis of proteins and peptides. Mass spectrometry (MS) is a key analytical technology in current proteomics and modern mass spectrometers generate large amounts of high-quality da...

  4. Analytical aspects of hydrogen exchange mass spectrometry

    Science.gov (United States)

    Engen, John R.; Wales, Thomas E.

    2016-01-01

    The analytical aspects of measuring hydrogen exchange by mass spectrometry are reviewed. The nature of analytical selectivity in hydrogen exchange is described followed by review of the analytical tools required to accomplish fragmentation, separation, and the mass spectrometry measurements under restrictive exchange quench conditions. In contrast to analytical quantitation that relies on measurements of peak intensity or area, quantitation in hydrogen exchange mass spectrometry depends on measuring a mass change with respect to an undeuterated or deuterated control, resulting in a value between zero and the maximum amount of deuterium that could be incorporated. Reliable quantitation is a function of experimental fidelity and to achieve high measurement reproducibility, a large number of experimental variables must be controlled during sample preparation and analysis. The method also reports on important qualitative aspects of the sample, including conformational heterogeneity and population dynamics. PMID:26048552

  5. A REVIEW ON MASS SPECTROMETRY DETECTORS

    Directory of Open Access Journals (Sweden)

    Khatri Neetu

    2012-10-01

    Full Text Available Mass spectrometry is an analytical technique for "weighing" molecules. Obviously, this is not done with a conventional scale or balance. Instead, mass spectrometry is based upon the principle of the motion of a charged particle that is called an ion, in an electric or magnetic field. The mass to charge ratio (m/z of the ion affects particles motion. Since the charge of an electron is known, the mass to charge ratio (m/z is a measurement of mass of an ion. Mass spectrometry research focuses on the formation of gas phase ions, and detection of ions. Detectors in mass spectrometer detect the separated ions according to m/z ratio. The main disadvantages of conventional detectors are very low sensitivity and poor detection efficiency. Detectors are of a great interest to a wide range of industrial, military, environmental and even biological applications. In recent developments, molecules of higher mass can also be detected and enhanced lifetime under the less than ideal environments typically encountered in mass spectrometers. This review deals in detail about the design, working and principle of mass spectrometric detectors and their recent developments.

  6. Mass spectrometry in natural product chemistry.

    Science.gov (United States)

    Clayton, E; Hill, H C; Reed, R I

    1966-01-01

    Some mass spectrometric techniques are described which seem applicable to investigating problems in natural product chemistry. One example is of a sample of 5 mcg of a compound being identified by comparison with an authentic sample of prostaglandin derivative. Compared were mass, ion content, and structure. In the prostaglandin/unknown substance comparison, high-resolution mass spectrometry resolved a quandary: apparent additional ions present in the unknown substance were shown to be an impurity. PMID:12262324

  7. Linear electric field mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    McComas, D.J.; Nordholt, J.E.

    1991-03-29

    A mass spectrometer is described having a low weight and low power requirement, for use in space. It can be used to analyze the ionized particles in the region of the spacecraft on which it is mounted. High mass resolution measurements are made by timing ions moving through a gridless cylindrically sysmetric linear electric field.

  8. [Imaging Mass Spectrometry in Histopathologic Analysis].

    Science.gov (United States)

    Yamazaki, Fumiyoshi; Seto, Mitsutoshi

    2015-04-01

    Matrix-assisted laser desorption/ionization (MALDI)-imaging mass spectrometry (IMS) enables visualization of the distribution of a range of biomolecules by integrating biochemical information from mass spectrometry with positional information from microscopy. IMS identifies a target molecule. In addition, IMS enables global analysis of biomolecules containing unknown molecules by detecting the ratio of the molecular weight to electric charge without any target, which makes it possible to identify novel molecules. IMS generates data on the distribution of lipids and small molecules in tissues, which is difficult to visualize with either conventional counter-staining or immunohistochemistry. In this review, we firstly introduce the principle of imaging mass spectrometry and recent advances in the sample preparation method. Secondly, we present findings regarding biological samples, especially pathological ones. Finally, we discuss the limitations and problems of the IMS technique and clinical application, such as in drug development. PMID:26536781

  9. Capillary electrophoresis electrospray ionization mass spectrometry interface

    Science.gov (United States)

    Smith, Richard D.; Severs, Joanne C.

    1999-01-01

    The present invention is an interface between a capillary electrophoresis separation capillary end and an electrospray ionization mass spectrometry emitter capillary end, for transporting an anolyte sample from a capillary electrophoresis separation capillary to a electrospray ionization mass spectrometry emitter capillary. The interface of the present invention has: (a) a charge transfer fitting enclosing both of the capillary electrophoresis capillary end and the electrospray ionization mass spectrometry emitter capillary end; (b) a reservoir containing an electrolyte surrounding the charge transfer fitting; and (c) an electrode immersed into the electrolyte, the electrode closing a capillary electrophoresis circuit and providing charge transfer across the charge transfer fitting while avoiding substantial bulk fluid transfer across the charge transfer fitting. Advantages of the present invention have been demonstrated as effective in providing high sensitivity and efficient analyses.

  10. Development of Gas Chromatographic Mass Spectrometry.

    Science.gov (United States)

    Hites, Ronald A

    2016-07-19

    Gas chromatographic mass spectrometry is now widely used for the quantitation and identification of organic compounds in almost any imaginable sample. These applications include the measurement of chlorinated dioxins in soil samples, the identification of illicit drugs in human blood, and the quantitation of accelerants in arson investigations, to name just a few. How did GC/MS get so popular? It turns out that it required parallel developments in mass spectrometry, gas chromatography, and computing and that no one person "invented" the technique. This Perspective traces this history from the 1950s until today. PMID:27384908

  11. Four decades of joy in mass spectrometry

    NARCIS (Netherlands)

    Nibbering, Nico M.M.

    2006-01-01

    Tremendous developments in mass spectrometry have taken place in the last 40 years. This holds for both the science and the instrumental revolutions in this field. In chemistry the research was heavily focused on organic molecules that upon electron ionization fragmented via complex mechanistic path

  12. Nanostructure-initiator mass spectrometry biometrics

    Energy Technology Data Exchange (ETDEWEB)

    Leclerc, Marion; Bowen, Benjamin; Northen, Trent

    2015-09-08

    Several embodiments described herein are drawn to methods of identifying an analyte on a subject's skin, methods of generating a fingerprint, methods of determining a physiological change in a subject, methods of diagnosing health status of a subject, and assay systems for detecting an analyte and generating a fingerprint, by nanostructure-initiator mass spectrometry (NIMS).

  13. Nanostructure-initiator mass spectrometry biometrics

    Science.gov (United States)

    Leclerc, Marion; Bowen, Benjamin; Northen, Trent

    2015-09-08

    Several embodiments described herein are drawn to methods of identifying an analyte on a subject's skin, methods of generating a fingerprint, methods of determining a physiological change in a subject, methods of diagnosing health status of a subject, and assay systems for detecting an analyte and generating a fingerprint, by nanostructure-initiator mass spectrometry (NIMS).

  14. Characterization of synthetic peptides by mass spectrometry

    DEFF Research Database (Denmark)

    Prabhala, Bala Krishna; Mirza, Osman Asghar; Højrup, Peter;

    2015-01-01

    Mass spectrometry (MS) is well suited for analysis of the identity and purity of synthetic peptides. The sequence of a synthetic peptide is most often known, so the analysis is mainly used to confirm the identity and purity of the peptide. Here, simple procedures are described for MALDI-TOF-MS an...

  15. Introduction to mass spectrometry-based proteomics

    DEFF Research Database (Denmark)

    Matthiesen, R.; Bunkenborg, J.

    2013-01-01

    for newcomers and give pointers to reference material. There are many applications of mass spectrometry in proteomics and each application is associated with some analytical choices, instrumental limitations and data processing steps that depend on the aim of the study and means of conducting it. Different...

  16. Atmospheric pressure femtosecond laser imaging mass spectrometry

    Science.gov (United States)

    Coello, Yves; Gunaratne, Tissa C.; Dantus, Marcos

    2009-02-01

    We present a novel imaging mass spectrometry technique that uses femtosecond laser pulses to directly ionize the sample. The method offers significant advantages over current techniques by eliminating the need of a laser-absorbing sample matrix, being suitable for atmospheric pressure sampling, and by providing 10μm resolution, as demonstrated here with a chemical image of vegetable cell walls.

  17. Application of mass spectrometry for metabolite identification.

    Science.gov (United States)

    Ma, Shuguang; Chowdhury, Swapan K; Alton, Kevin B

    2006-06-01

    Metabolism studies play a pivotal role in drug discovery and development. Characterization of metabolic "hot-spots" as well as reactive and pharmacologically active metabolites is critical to designing new drug candidates with improved metabolic stability, toxicological profile and efficacy. Metabolite identification in the preclinical species used for safety evaluation is required in order to determine whether human metabolites have been adequately tested during non-clinical safety assessment. From an instrumental standpoint, high performance liquid chromatography (HPLC) coupled with mass spectrometry (MS) dominates all analytical tools used for metabolite identification. The general strategies employed for metabolite identification in both drug discovery and drug development settings together with sample preparation techniques are reviewed herein. These include a discussion of the various ionization methods, mass analyzers, and tandem mass spectrometry (MS/MS) techniques that are used for structural characterization in a modern drug metabolism laboratory. Mass spectrometry-based techniques, such as stable isotope labeling, on-line H/D exchange, accurate mass measurement to enhance metabolite identification and recent improvements in data acquisition and processing for accelerating metabolite identification are also described. Rounding out this review, we offer additional thoughts about the potential of alternative and less frequently used techniques such as LC-NMR/MS, CRIMS and ICPMS. PMID:16787159

  18. Accelerator mass spectrometry: state of the art

    Energy Technology Data Exchange (ETDEWEB)

    Tuniz, C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    Accelerator Mass Spectrometry (AMS) is the analytical technique of choice for the detection of long-lived radionuclides which cannot be practically analysed with decay counting or conventional mass spectrometry. The main use of AMS has been in the analysis of radiocarbon and other cosmogenic radionuclides for archaeological, geological and environmental applications. In addition, AMS has been recently applied in biomedicine to study exposure of human tissues to chemicals and biomolecules at attomole levels. There is also a world-wide effort to analyse rare nuclides of heavier masses, such as long-lived actinides, with important applications in safeguards and nuclear waste disposal. The use of AMS is limited by the expensive accelerator technology required and there are several attempts to develop smaller and cheaper AMS spectrometers. 5 refs.

  19. Space Applications of Mass Spectrometry. Chapter 31

    Science.gov (United States)

    Hoffman, John H.; Griffin, Timothy P.; Limero, Thomas; Arkin, C. Richard

    2010-01-01

    Mass spectrometers have been involved in essentially all aspects of space exploration. This chapter outlines some of these many uses. Mass spectrometers have not only helped to expand our knowledge and understanding of the world and solar system around us, they have helped to put man safely in space and expand our frontier. Mass spectrometry continues to prove to be a very reliable, robust, and flexible analytical instrument, ensuring that its use will continue to help aid our investigation of the universe and this small planet that we call home.

  20. Thermal ionisation mass spectrometry (TIMS): what, how and why?

    International Nuclear Information System (INIS)

    Thermal ionisation mass spectrometry (TIMS) is one of the oldest mass spectrometric techniques, which has been used for determining the isotopic composition and concentration of different elements using isotope dilution. In spite of the introduction of many other inorganic mass spectrometric techniques like spark source mass spectrometry (SSMS), glow discharge mass spectrometry (GDMS), inductively coupled plasma-mass spectrometry (ICP-MS), secondary ion mass spectrometry (SIMS), the TIMS technique plays the role of a definitive analytical methodology and still occupies a unique position in terms of its capabilities with respect to precision and accuracy as well as sensitivity

  1. High resolution laser mass spectrometry bioimaging.

    Science.gov (United States)

    Murray, Kermit K; Seneviratne, Chinthaka A; Ghorai, Suman

    2016-07-15

    Mass spectrometry imaging (MSI) was introduced more than five decades ago with secondary ion mass spectrometry (SIMS) and a decade later with laser desorption/ionization (LDI) mass spectrometry (MS). Large biomolecule imaging by matrix-assisted laser desorption/ionization (MALDI) was developed in the 1990s and ambient laser MS a decade ago. Although SIMS has been capable of imaging with a moderate mass range at sub-micrometer lateral resolution from its inception, laser MS requires additional effort to achieve a lateral resolution of 10μm or below which is required to image at the size scale of single mammalian cells. This review covers untargeted large biomolecule MSI using lasers for desorption/ionization or laser desorption and post-ionization. These methods include laser microprobe (LDI) MSI, MALDI MSI, laser ambient and atmospheric pressure MSI, and near-field laser ablation MS. Novel approaches to improving lateral resolution are discussed, including oversampling, beam shaping, transmission geometry, reflective and through-hole objectives, microscope mode, and near-field optics. PMID:26972785

  2. Online atmospheric pressure chemical ionization ion trap mass spectrometry (APCI-IT-MSn) for measuring organic acids in concentrated bulk aerosol – a laboratory and field study

    OpenAIRE

    Williams, J.; Kulmala, M.; D. R. Worsnop; Junninen, H.; Petäjä, T.; Ehn, M.; Brüggemann, M; M. Äijälä; Vogel, A. L.; Hoffmann, T.

    2013-01-01

    The field application of an aerosol concentrator in conjunction with an atmospheric pressure chemical ionization ion trap mass spectrometer (APCI-IT-MS) at the boreal forest station SMEAR II at Hyytiälä, Finland, is demonstrated in this study. APCI is a soft-ionization technique allowing online measurements of organic acids in the gas and particle phase. The detection limit for the acid species in the particle phase was improved by a factor of 7.5 to 11 (e.g. ∼40 ng m3 for pinonic acid) b...

  3. Online atmospheric pressure chemical ionization ion trap mass spectrometry (APCI-IT-MSn) for measuring organic acids in concentrated bulk aerosol – a laboratory and field study

    OpenAIRE

    Williams, J.; Kulmala, M.; D. R. Worsnop; Junninen, H.; Petäjä, T.; Ehn, M.; Brüggemann, M; M. Äijälä; Vogel, A. L.; Hoffmann, T.

    2012-01-01

    The field application of an aerosol concentrator in conjunction with an atmospheric pressure chemical ionization ion trap mass spectrometer (APCI-IT-MS) at the boreal forest station SMEAR II at Hyytiälä, Finland, is demonstrated in this study. APCI is a soft ionization technique allowing online measurements of organic acids in the gas and particle phase. The detection limit for the acid species in the particle phase was increased by a factor of 7.5 to 11 (e.g. ~40 ng m−3 for pinonic ac...

  4. Mass spectrometry imaging and profiling of single cells

    OpenAIRE

    Lanni, Eric J.; Rubakhin, Stanislav S.; Sweedler, Jonathan V.

    2012-01-01

    Mass spectrometry imaging and profiling of individual cells and subcellular structures provide unique analytical capabilities for biological and biomedical research, including determination of the biochemical heterogeneity of cellular populations and intracellular localization of pharmaceuticals. Two mass spectrometry technologies—secondary ion mass spectrometry (SIMS) and matrix assisted laser desorption ionization mass spectrometry (MALDI MS)—are most often used in micro-bioanalytical inves...

  5. Boundaries of mass resolution in native mass spectrometry

    NARCIS (Netherlands)

    Lössl, Philip; Snijder, Joost; Heck, Albert J R

    2014-01-01

    Over the last two decades, native mass spectrometry (MS) has emerged as a valuable tool to study intact proteins and noncovalent protein complexes. Studied experimental systems range from small-molecule (drug)-protein interactions, to nanomachineries such as the proteasome and ribosome, to even viru

  6. Laser-cooling-assisted mass spectrometry

    CERN Document Server

    Schneider, Christian; Chen, Kuang; Sullivan, Scott T; Hudson, Eric R

    2014-01-01

    Mass spectrometry is used in a wide range of scientific disciplines including proteomics, pharmaceutics, forensics, and fundamental physics and chemistry. Given this ubiquity, there is a worldwide effort to improve the efficiency and resolution of mass spectrometers. However, the performance of all techniques is ultimately limited by the initial phase-space distribution of the molecules being analyzed. Here, we dramatically reduce the width of this initial phase-space distribution by sympathetically cooling the input molecules with laser-cooled, co-trapped atomic ions, improving both the mass resolution and detection efficiency of a time-of-flight mass spectrometer by over an order of magnitude. Detailed molecular dynamics simulations verify the technique and aid with evaluating its effectiveness. Our technique appears to be applicable to other types of mass spectrometers.

  7. Spatial neuroproteomics using imaging mass spectrometry.

    Science.gov (United States)

    Hanrieder, Jörg; Malmberg, Per; Ewing, Andrew G

    2015-07-01

    The nervous system constitutes arguably the most complicated and least understood cellular network in the human body. This consequently manifests itself in the fact that the molecular bases of neurodegenerative diseases remain unknown. The limited understanding of neurobiological mechanisms relates directly to the lack of appropriate bioanalytical technologies that allow highly resolved, sensitive, specific and comprehensive molecular imaging in complex biological matrices. Imaging mass spectrometry (IMS) is an emerging technique for molecular imaging. The technique is characterized by its high chemical specificity allowing comprehensive, spatial protein and peptide profiling in situ. Imaging MS represents therefore a powerful approach for investigation of spatio-temporal protein and peptide regulations in CNS derived tissue and cells. This review aims to provide a concise overview of major developments and applications concerning imaging mass spectrometry based protein and peptide profiling in neurobiological and biomedical research. This article is part of a Special Issue entitled: Neuroproteomics: Applications in Neuroscience and Neurology. PMID:25582083

  8. Isotope ratio mass spectrometry in oceanic studies

    International Nuclear Information System (INIS)

    Isotope ratio mass spectrometry (IRMS) is an important and well established method in many scientific fields as analytical chemistry (isotope dilution MS), physical chemistry, nuclear sciences and technology, environmental, agricultural, geological isotope dating, archaeometric, cosmic, bioavailability and nutrition studies, food authentication and adulteration control, elucidation of chemical reaction mechanism, isotope effect studies on chemical reactions and isotope enrichment/separation processes. This paper is aimed to provide a brief summary of IRMS contribution to sea and oceanic studies

  9. Detection of Gunshot Residues Using Mass Spectrometry

    OpenAIRE

    Regina Verena Taudte; Alison Beavis; Lucas Blanes; Nerida Cole; Philip Doble; Claude Roux

    2014-01-01

    In recent years, forensic scientists have become increasingly interested in the detection and interpretation of organic gunshot residues (OGSR) due to the increasing use of lead- and heavy metal-free ammunition. This has also been prompted by the identification of gunshot residue- (GSR-) like particles in environmental and occupational samples. Various techniques have been investigated for their ability to detect OGSR. Mass spectrometry (MS) coupled to a chromatographic system is a powerful t...

  10. Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

    Science.gov (United States)

    Wang, Daojing; Yang, Peidong; Kim, Woong; Fan, Rong

    2011-09-20

    Novel and significantly simplified procedures for fabrication of fully integrated nanoelectrospray emitters have been described. For nanofabricated monolithic multinozzle emitters (NM.sup.2 emitters), a bottom up approach using silicon nanowires on a silicon sliver is used. For microfabricated monolithic multinozzle emitters (M.sup.3 emitters), a top down approach using MEMS techniques on silicon wafers is used. The emitters have performance comparable to that of commercially-available silica capillary emitters for nanoelectrospray mass spectrometry.

  11. Laser mass spectrometry for selective ultratrace determination

    CERN Document Server

    Wendt, K; Müller, P; Nörtershäuser, W; Schmitt, A; Trautmann, N; Bushaw, B A

    1999-01-01

    Resonance ionization mass spectrometry has been explored in respect to its capabilities for isobaric suppression, isotopic selectivity, and overall efficiency. Theoretical calculations within the density matrix formalism on coherent multi-step excitation processes predict high specifications, which have been confirmed by spectroscopic measurements in Ca and which make the technique attractive for ultratrace detection. Analytical applications are found in the determination of the ultratrace isotope sup 4 sup 1 Ca for cosmochemical, radiodating, and medical applications.

  12. Trends in mass spectrometry instrumentation for proteomics.

    Science.gov (United States)

    Smith, Richard D

    2002-12-01

    Mass spectrometry has become a primary tool for proteomics because of its capabilities for rapid and sensitive protein identification and quantitation. It is now possible to identify thousands of proteins from microgram sample quantities in a single day and to quantify relative protein abundances. However, the need for increased capabilities for proteome measurements is immense and is now driving both new strategies and instrument advances. These developments include those based on integration with multi-dimensional liquid separations and high accuracy mass measurements and promise more than order of magnitude improvements in sensitivity, dynamic range and throughput for proteomic analyses in the near future.

  13. Trends in mass spectrometry instrumentation for proteomics

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Richard D.(BATTELLE (PACIFIC NW LAB))

    2002-12-01

    Mass spectrometry has become a primary tool for proteomics due to its capabilities for rapid and sensitive protein identification and quantitation. It is now possible to identify thousands of proteins from microgram sample quantities in a single day and to quantify relative protein abundances. However, the needs for increased capabilities for proteome measurements are immense and are now driving both new strategies and instrument advances. These developments include those based on integration with multi-dimensional liquid separations and high accuracy mass measurements, and promise more than order of magnitude improvements in sensitivity, dynamic range, and throughput for proteomic analyses in the near future.

  14. Ultrahigh resolution mass spectrometric characterization of organic aerosol from European and Chinese cities

    Science.gov (United States)

    Wang, Kai; Huang, Ru-Jin; Hoffmann, Thorsten

    2016-04-01

    Organic aerosol constitutes a substantial fraction (20-90%) of submicrometer aerosol mass, playing an important role in air quality and human health. Over the past few years, ultra-high resolution mass spectrometry (UHRMS) has been applied to elucidate the chemical composition of ambient aerosols. However, most of the UHRMS studies used direct infusion without prior separation by liquid chromatography, which may cause the loss of individual compound information and interference problems. In the present study, urban ambient aerosol with particle diameter Beijing, China, respectively. Two pretreatment procedures were applied to extract the organic compounds from the filter samples: One method uses a mixture of acetonitrile and water, the other uses pure water and prepared for the extraction of humic-like substances. The extracts were analyzed by ultra-high-performance liquid chromatography coupled with an Orbitrap mass spectrometer in both negative and the positive modes. The effects of pretreatment procedures on the characterization of organic aerosol and the city-wise difference in chemical composition of organic aerosol will be discussed in detail.

  15. Evolution of organic aerosol mass spectra upon heating: implications for OA phase and partitioning behavior

    Energy Technology Data Exchange (ETDEWEB)

    UC Davis; Cappa, Christopher D.; Wilson, Kevin R.

    2010-10-28

    Vacuum Ultraviolet (VUV) photoionization mass spectrometry has been used to measure the evolution of chemical composition for two distinct organic aerosol types as they are passed through a thermodenuder at different temperatures. The two organic aerosol types considered are primary lubricating oil (LO) aerosol and secondary aerosol from the alpha-pinene + O3 reaction (alphaP). The evolution of the VUV mass spectra for the two aerosol types with temperature are observed to differ dramatically. For LO particles, the spectra exhibit distinct changes with temperature in which the lower m/z peaks, corresponding to compounds with higher vapor pressures, disappear more rapidly than the high m/z peaks. In contrast, the alphaP aerosol spectrum is essentially unchanged by temperature even though the particles experience significant mass loss due to evaporation. The variations in the LO spectra are found to be quantitatively in agreement with expectations from absorptive partitioning theory whereas the alphaP spectra suggest that the evaporation of alphaP derived aerosol appears to not be governed by partitioning theory. We postulate that this difference arises from the alphaP particles existing as in a glassy state instead of having the expected liquid-like behavior. To reconcile these observations with decades of aerosol growth measurements, which indicate that OA formation is described by equilibrium partitioning, we present a conceptual model wherein the secondary OA is formed and then rapidly converted from an absorbing form to a non-absorbing form. The results suggest that although OA growth may be describable by equilibrium partitioning theory, the properties of organic aerosol once formed may differ significantly from the properties determined in the equilibrium framework.

  16. Evolution of organic aerosol mass spectra upon heating: implications for OA phase and partitioning behavior

    Science.gov (United States)

    Cappa, C. D.; Wilson, K. R.

    2011-03-01

    Vacuum Ultraviolet (VUV) photoionization mass spectrometry has been used to measure the evolution of chemical composition for two distinct organic aerosol types as they are passed through a thermodenuder at different temperatures. The two organic aerosol types considered are primary lubricating oil (LO) aerosol and secondary aerosol from the α-pinene + O3 reaction (αP). The evolution of the VUV mass spectra for the two aerosol types with temperature are observed to differ dramatically. For LO particles, the spectra exhibit distinct changes with temperature in which the lower m/z peaks, corresponding to compounds with higher vapor pressures, disappear more rapidly than the high m/z peaks. In contrast, the αP aerosol spectrum is essentially unchanged by temperature even though the particles experience significant mass loss due to evaporation. The variations in the LO spectra are found to be quantitatively in agreement with expectations from absorptive partitioning theory whereas the αP spectra suggest that the evaporation of αP derived aerosol appears to not be governed by partitioning theory. We postulate that this difference arises from diffusivity within the αP particles being sufficiently slow that they do not exhibit the expected liquid-like behavior and perhaps exist in a glassy state. To reconcile these observations with decades of aerosol growth measurements, which indicate that OA formation is described by equilibrium partitioning, we present a conceptual model wherein the secondary OA is formed and then rapidly converted from an absorbing form to a non-absorbing form. The results suggest that, although OA growth may be describable by equilibrium partitioning theory, the properties of organic aerosol once formed may differ significantly from the properties determined in the equilibrium framework.

  17. Accelerator Mass Spectrometry (AMS) 1977-1987

    Science.gov (United States)

    Gove, H. E.; Purser, K. H.; Litherland, A. E.

    2010-04-01

    The eleventh Accelerator Mass Spectrometry (AMS 11) Conference took place in September 2008, the Thirtieth Anniversary of the first Conference. That occurred in 1978 after discoveries with nuclear physics accelerators in 1977. Since the first Conference there have now been ten further conferences on the development and applications of what has become known as AMS. This is the accepted acronym for the use of accelerators, together with nuclear and atomic physics techniques, to enhance the performance of mass spectrometers for the detection and measurement of rare long-lived radioactive elements such as radiocarbon. This paper gives an outline of the events that led to the first conference together with a brief account of the first four conferences before the introduction of the second generation of accelerator mass spectrometers at AMS 5.

  18. Isotope dilution inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    The potential of isotope dilution inductively coupled plasma mass spectrometry (ICP-MS) was evaluated for the determination of trace amounts of uranium and thorium in silicate rocks. Compared with conventional isotope dilution methods using thermal ionization mass spectrometers, the major benefit is a large increase in sample through-put without a significant decrease in precision and accuracy. This results from direct liquid sampling at atmospheric pressure and from the capability of measuring isotope ratios on raw solutions, without chemical separation of the analytes from the matrix elements. Isotope dilution ICP-MS alleviates the need for matrix-matched standards. Further, it is insensitive to possible causes of intensity drift (e.g., clogging of the plasma/mass spectrometer interface and defocusing of the ion beam) and to chemical effects (e.g. oxide formulation). Results obtained on some international rock standards are in good agreement with recommended values. (author). 26 refs.; 1 fig., tabs

  19. Mass spectrometry of fluorocarbon-labeled glycosphingolipids

    DEFF Research Database (Denmark)

    Li, Yunsen; Arigi, Emma; Eichert, Heather;

    2010-01-01

    A method for generation of novel fluorocarbon derivatives of glycosphingolipids (GSLs) with high affinity for fluorocarbon phases has been developed, and their potential applications to mass spectrometry (MS)-based methodologies for glycosphingolipidomics have been investigated. Sphingolipid...... with subsequent per-N,O-methylation was established for the F-tagged Gb(3) Cer and purified gangliosides, and extensive mass spectra (MS(1) and MS(2)) consistent with all of the expected products were acquired. The potential use of F-tagged derivatives for a comprehensive MS based profiling application....... The methods described thus provide a new avenue for rapid GSL recovery or cleanup, potentially compatible with a variety of platforms for mass spectrometric profiling and structure analysis, as well as parallel analysis of functional interactions....

  20. New directions for accelerator mass spectrometry technology

    International Nuclear Information System (INIS)

    The influence on accelerator mass spectrometry (AMS) of developments in other fields is reviewed and three examples are discussed in detail. The appropriate use of electric and magnetic analysers with small AMS systems (129I, for nuclear fuel monitoring and ocean circulation tracer studies. The inclusion of gas chromatography technology extends the capability of AMS to applications which require large numbers of samples with rapid turn-around. The adaptation of chemical reaction cell technology to negative ion beams adds new isobar selection capability to AMS and will permit analyses of isotopes such as 36Cl on small AMS systems. (author)

  1. Neutral particle Mass Spectrometry with Nanomechanical Systems

    CERN Document Server

    Sage, Eric; Alava, Thomas; Morel, Robert; Dupré, Cécilia; Hanay, Mehmet Selim; Duraffourg, Laurent; Masselon, Christophe; Hentz, Sébastien

    2014-01-01

    Current approaches to Mass Spectrometry (MS) necessarily rely on the ionization of the analytes of interest and subsequent spectrum interpretation is based on the mass-to-charge ratios of the ions. The resulting charge state distribution can be very complex for high-mass species which may hinder correct interpretation. A new form of MS analysis based on Nano-Electro-Mechanical Systems (NEMS) was recently demonstrated with high-mass ions. Thanks to a dedicated setup comprising both conventional time-of-flight MS (TOF-MS) and NEMS-MS in-situ, we show here for the first time that NEMS-MS analysis is insensitive to charge state: it provides one single peak regardless of the species charge state, highlighting effective clarification over existing MS analysis. All charged particles were thereafter removed from the beam electrostatically, and unlike TOF-MS, NEMS-MS retained its ability to perform mass measurements. This constitutes the first unequivocal measurement of mass spectra of neutral particles. This ability ...

  2. Mass spectrometry imaging: applications to food science.

    Science.gov (United States)

    Taira, Shu; Uematsu, Kohei; Kaneko, Daisaku; Katano, Hajime

    2014-01-01

    Two-dimensional mass spectrometry (MS) analysis of biological samples by means of what is called MS imaging (MSI) is now being used to analyze analyte distribution because it facilitates determination of the existence (what is it?) and localization (where is it?) of biomolecules. Reconstruction of mass image by target signal is given after two-dimensional MS measurements on a sample section. From only one section, we can understand the existence and localization of many molecules without the need of an antibody or fluorescent reagent. In this review, we introduce the analysis of localization of functional constituents and nutrients in herbal medicine products via MSI. The ginsenosides were mainly distributed in the periderm and the tip region of the root of Panax ginseng. The capsaicin was found to be more dominantly localized in the placenta than the pericarp and seed in Capsicum fruits. We expect MSI will be a useful technique for optical quality assurance.

  3. Emerging Technologies in Mass Spectrometry Imaging

    CERN Document Server

    Jungmann, Julia H

    2013-01-01

    Mass spectrometry imaging (MSI) as an analytical tool for bio-molecular and bio-medical research targets, accurate compound localization and identification. In terms of dedicated instrumentation, this translates into the demand for more detail in the image dimension (spatial resolution) and in the spectral dimension (mass resolution and accuracy), preferably combined in one instrument. At the same time, large area biological tissue samples require fast acquisition schemes, instrument automation and a robust data infrastructure. This review discusses the analytical capabilities of an "ideal" MSI instrument for bio-molecular and bio-medical molecular imaging. The analytical attributes of such an ideal system are contrasted with technological and methodological challenges in MSI. In particular, innovative instrumentation for high spatial resolution imaging in combination with high sample throughput is discussed. Detector technology that targets various shortcomings of conventional imaging detector systems is hig...

  4. Damping effects in Penning trap mass spectrometry

    CERN Document Server

    George, S; Kowalska, M; Dworschak, M; Neidherr, D; Blaum, K; Schweikhard, L; Ramirez, E M; Breitenfeldt, M; Kretzschmar, M; Herfurth, F; Schwarz, S; Herlert, A

    2011-01-01

    Collisions of ions with residual gas atoms in a Penning trap can have a strong influence on the trajectories of the ions, depending on the atom species and the gas pressure. We report on investigations of damping effects in time-of-flight ion-cyclotron resonance mass spectrometry with the Penning trap mass spectrometers ISOLTRAP at ISOLDE/CERN (Geneva, Switzerland) and SHIPTRAP at GSI (Darmstadt, Germany). The work focuses on the interconversion of the magnetron and cyclotron motional modes, in particular the modification of the resonance profiles for quadrupolar excitation due to the damping effect of the residual gas. Extensive experiments have been performed with standard and Ramsey excitation schemes. The results are in good agreement with predictions obtained by analytical continuation of the formulae for the undamped case.

  5. Proteome analysis of adenovirus using mass spectrometry.

    Science.gov (United States)

    Lind, Sara Bergström; Artemenko, Konstantin A; Pettersson, Ulf

    2014-01-01

    Analysis of proteins and their posttranslational modifications is important for understanding different biological events. For analysis of viral proteomes, an optimal protocol includes production of a highly purified virus that can be investigated with a high-resolving analytical method. In this Methods in Molecular Biology paper we describe a working strategy for how structural proteins in the Adenovirus particle can be studied using liquid chromatography-high-resolving mass spectrometry. This method provides information on the chemical composition of the virus particle. Further, knowledge about amino acids carrying modifications that could be essential for any part of the virus life cycle is collected. We describe in detail alternatives available for preparation of virus for proteome analysis as well as choice of mass spectrometric instrumentation suitable for this kind of analysis.

  6. Mass Spectrometry on Future Mars Landers

    Science.gov (United States)

    Brinckerhoff, W. B.; Mahaffy, P. R.

    2011-01-01

    Mass spectrometry investigations on the 2011 Mars Science Laboratory (MSL) and the 2018 ExoMars missions will address core science objectives related to the potential habitability of their landing site environments and more generally the near-surface organic inventory of Mars. The analysis of complex solid samples by mass spectrometry is a well-known approach that can provide a broad and sensitive survey of organic and inorganic compounds as well as supportive data for mineralogical analysis. The science value of such compositional information is maximized when one appreciates the particular opportunities and limitations of in situ analysis with resource-constrained instrumentation in the context of a complete science payload and applied to materials found in a particular environment. The Sample Analysis at Mars (SAM) investigation on MSL and the Mars Organic Molecule Analyzer (MOMA) investigation on ExoMars will thus benefit from and inform broad-based analog field site work linked to the Mars environments where such analysis will occur.

  7. [Application of mass spectrometry in mycobacteria].

    Science.gov (United States)

    Alcaide, Fernando; Palop-Borrás, Begoña; Domingo, Diego; Tudó, Griselda

    2016-06-01

    To date, more than 170 species of mycobacteria have been described, of which more than one third may be pathogenic to humans, representing a significant workload for microbiology laboratories. These species must be identified in clinical practice, which has long been a major problem due to the shortcomings of conventional (phenotypic) methods and the limitations and complexity of modern methods largely based on molecular biology techniques. The aim of this review was to briefly describe different aspects related to the use of MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight) mass spectrometry (MS) for the identification of mycobacteria. Several difficulties are encountered with the use of this methodology in these microorganisms mainly due to the high pathogenicity of some mycobacteria and the peculiar structure of their cell wall, requiring inactivation and special protein extraction protocols. We also analysed other relevant aspects such as culture media, the reference methods employed (gold standard) in the final identification of the different species, the cut-off used to accept data as valid, and the databases of the different mass spectrometry systems available. MS has revolutionized diagnosis in modern microbiology; however, specific improvements are needed to consolidate the use of this technology in mycobacteriology. PMID:27389290

  8. X-ray fluorescence spectrometry for high throughput analysis of atmospheric aerosol samples: The benefits of synchrotron X-rays

    Science.gov (United States)

    Bukowiecki, Nicolas; Lienemann, Peter; Zwicky, Christoph N.; Furger, Markus; Richard, Agnes; Falkenberg, Gerald; Rickers, Karen; Grolimund, Daniel; Borca, Camelia; Hill, Matthias; Gehrig, Robert; Baltensperger, Urs

    2008-09-01

    The determination of trace element mass concentrations in ambient air with a time resolution higher than one day represents an urgent need in atmospheric research. It involves the application of a specific technique both for the aerosol sampling and the subsequent analysis of the collected particles. Beside the intrinsic sensitivity of the analytical method, the sampling interval and thus the quantity of collected material that is available for subsequent analysis is a major factor driving the overall trace element detection power. This is demonstrated for synchrotron radiation X-ray fluorescence spectrometry (SR-XRF) of aerosol samples collected with a rotating drum impactor (RDI) in hourly intervals and three particle size ranges. The total aerosol mass on the 1-h samples is in the range of 10 µg. An experimental detection of the nanogram amounts of trace elements with the help of synchrotron X-rays was only achievable by the design of a fit-for-purpose sample holder system, which considered the boundary conditions both from particle sampling and analysis. A 6-µm polypropylene substrate film has evolved as substrate of choice, due to its practical applicability during sampling and its suitable spectroscopic behavior. In contrast to monochromatic excitation conditions, the application of a 'white' beam led to a better spectral signal-to-background ratio. Despite the low sample mass, a counting time of less than 30 s per 1-h aerosol sample led to sufficient counting statistics. Therefore the RDI-SR-XRF method represents a high-throughput analysis procedure without the need for any sample preparation. The analysis of a multielemental mass standard film by SR-XRF, laboratory-based wavelength-dispersive XRF spectrometry and laboratory-based micro XRF spectrometry showed that the laboratory-based methods were no alternatives to the SR-XRF method with respect to sensitivity and efficiency of analysis.

  9. Retrieval of the aerosol direct radiative effect over clouds from spaceborne spectrometry

    Science.gov (United States)

    Graaf, M.; Tilstra, L. G.; Wang, P.; Stammes, P.

    2012-04-01

    The solar radiative absorption by an aerosol layer above clouds is quantified using passive satellite spectrometry from the ultraviolet (UV) to the shortwave infrared (SWIR). UV-absorbing aerosols have a strong signature that can be detected using UV reflectance measurements, even when above clouds. Since the aerosol extinction optical thickness decreases rapidly with increasing wavelength for biomass burning aerosols, the properties of the clouds below the aerosol layer can be retrieved in the SWIR, where aerosol extinction optical thickness is sufficiently small. Using radiative transfer computations, the contribution of the clouds to the reflected radiation can be modeled for the entire solar spectrum. In this way, cloud and aerosol effects can be separated for a scene with aerosols above clouds. Aerosol microphysical assumptions and retrievals are avoided by modeling only the pure (aerosol-free) cloud spectra. An algorithm was developed using the spaceborne spectrometer Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY). The aerosol direct radiative effect (DRE) over clouds over the South Atlantic Ocean west of Africa, averaged through August 2006 was found to be 23 ± 8 Wm-2 with a mean variation over the region in this month of 22 Wm-2. The largest aerosol DRE over clouds found in that month was 132 ± 8 Wm-2. The algorithm can be applied to any instrument, or a combination of instruments, that measures UV, visible and SWIR reflectances at the top of the atmosphere (TOA) simultaneously.

  10. Ambient ionization mass spectrometry: A tutorial

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Min-Zong; Cheng, Sy-Chi; Cho, Yi-Tzu [Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Shiea, Jentaie, E-mail: jetea@fac.nsysu.edu.tw [Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Cancer Center, Kaohsiung Medical University, Kaohsiung, Taiwan (China)

    2011-09-19

    Highlights: {yields} Ambient ionization technique allows the direct analysis of sample surfaces with little or no sample pretreatment. {yields} We sort ambient ionization techniques into three main analytical strategies, direct ionization, direct desorption/ionization, and two-step ionization. {yields} The underlying principles of operation, ionization processes, detecting mass ranges, sensitivity, and representative applications of these techniques are described and compared. - Abstract: Ambient ionization is a set of mass spectrometric ionization techniques performed under ambient conditions that allows the direct analysis of sample surfaces with little or no sample pretreatment. Using combinations of different types of sample introduction systems and ionization methods, several novel techniques have been developed over the last few years with many applications (e.g., food safety screening; detection of pharmaceuticals and drug abuse; monitoring of environmental pollutants; detection of explosives for antiterrorism and forensics; characterization of biological compounds for proteomics and metabolomics; molecular imaging analysis; and monitoring chemical and biochemical reactions). Electrospray ionization and atmospheric pressure chemical ionization are the two main ionization principles most commonly used in ambient ionization mass spectrometry. This tutorial paper provides a review of the publications related to ambient ionization techniques. We describe and compare the underlying principles of operation, ionization processes, detecting mass ranges, sensitivity, and representative applications of these techniques.

  11. Multinozzle Emitter Arrays for Nanoelectrospray Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Pan; Wang, Hung-Ta; Yang, Peidong; Wang, Daojing

    2011-06-16

    Mass spectrometry (MS) is the enabling technology for proteomics and metabolomics. However, dramatic improvements in both sensitivity and throughput are still required to achieve routine MS-based single cell proteomics and metabolomics. Here, we report the silicon-based monolithic multinozzle emitter array (MEA), and demonstrate its proof-of-principle applications in high-sensitivity and high-throughput nanoelectrospray mass spectrometry. Our MEA consists of 96 identical 10-nozzle emitters in a circular array on a 3-inch silicon chip. The geometry and configuration of the emitters, the dimension and number of the nozzles, and the micropillar arrays embedded in the main channel, can be systematically and precisely controlled during the microfabrication process. Combining electrostatic simulation and experimental testing, we demonstrated that sharpened-end geometry at the stem of the individual multinozzle emitter significantly enhanced the electric fields at its protruding nozzle tips, enabling sequential nanoelectrospray for the high-density emitter array. We showed that electrospray current of the multinozzle emitter at a given total flow rate was approximately proportional to the square root of the number of its spraying-nozzles, suggesting the capability of high MS sensitivity for multinozzle emitters. Using a conventional Z-spray mass spectrometer, we demonstrated reproducible MS detection of peptides and proteins for serial MEA emitters, achieving sensitivity and stability comparable to the commercial capillary emitters. Our robust silicon-based MEA chip opens up the possibility of a fully-integrated microfluidic system for ultrahigh-sensitivity and ultrahigh-throughput proteomics and metabolomics.

  12. Mass spectrometry for high-throughput metabolomics analysis of urine

    OpenAIRE

    Abdelrazig, Salah M.A.

    2015-01-01

    Direct electrospray ionisation-mass spectrometry (direct ESI-MS), by omitting the chromatographic step, has great potential for application as a high-throughput approach for untargeted urine metabolomics analysis compared to liquid chromatography-mass spectrometry (LC-MS). The rapid development and technical innovations revealed in the field of ambient ionisation MS such as nanoelectrospray ionisation (nanoESI) chip-based infusion and liquid extraction surface analysis mass spectrometry (LESA...

  13. Effect of dimethylamine on the gas phase sulfuric acid concentration measured by Chemical Ionization Mass Spectrometry

    OpenAIRE

    L. Rondo; Flagan, R. C.

    2016-01-01

    Sulfuric acid is widely recognized as a very important substance driving atmospheric aerosol nucleation. Based on quantum chemical calculations it has been suggested that the quantitative detection of gas phase sulfuric acid (H_2SO_4) by use of Chemical Ionization Mass Spectrometry (CIMS) could be biased in the presence of gas phase amines such as dimethylamine (DMA). An experiment (CLOUD7 campaign) was set up at the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber to investigate the quantita...

  14. Characterisation of DEFB107 by mass spectrometry

    Science.gov (United States)

    McCullough, Bryan J.; Eastwood, Hayden; Clark, Dave J.; Polfer, Nick C.; Campopiano, Dominic J.; Dorin, Julia A.; Maxwell, Alison; Langley, Ross J.; Govan, John R. W.; Bernstein, Summer L.; Bowers, Michael T.; Barran, Perdita E.

    2006-05-01

    Mammalian defensins are small endogenous cationic proteins which form a class of antimicrobial peptides that is part of the innate immune response of all mammalian species [R. Lehrer, Nat. Rev. Microbiol. 2 (9) (2004) 727; T. Ganz, R.I. Lehrer, Curr. Opin. Immunol. 6 (4) (1994) 584] [1] and [2]. We have developed mass spectrometry based strategies for characterising the structure-activity relationship of defensins [D.J. Campopiano, D.J. Clarke, N.C. Polfer, P.E. Barran, R.J. Langley, J.R.W. Govan, A. Maxwell, J.R. Dorin, J. Biol. Chem. 279 (47) (2004) 48671; P.E. Barran, N.C. Polfer, D.J. Campopiano, D.J. Clarke, P.R.R. Langridge-Smith, R.J. Langley, J.R.W. Govan, A. Maxwell, J.R. Dorin, R.P. Millar, M.T. Bowers, Int. J. Mass Spectrom. 240 (2005) 273] [3] and [4], and here we present data obtained from a five cysteine containing [beta]-defensin, DEFB107. The synthetic product of this human defensin exists with a glutathione capping group, its oxidation state and disulphide connectivity have been determined via accurate mass measurements and peptide mass mapping respectively, and despite possessing three disulphide bridges, it does not fit the [beta]-defensin canonical motif. With the use of molecular modelling, we have generated candidate geometries to discern the influence of disulphide bridging on the overall tertiary structure of DEFB107. These are compared with experimental results from ion mobility measurements. Defensins display activity against a wide variety of pathogens including both gram-negative and gram-positive bacteria. Their mechanism of mode of action is unknown, but is believed to involve defensin aggregation at cell surfaces, followed by cell permeabilisation and hence deathE To probe this mechanism, the localisation of DEFB107 in synthetic vesicles was studied using H/D exchange and mass spectrometry. The results obtained are used to analyse the antimicrobial activity of DEFB107.

  15. New high temperature plasmas and sample introduction systems for analytical atomic emission and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Montaser, A.

    1992-01-01

    New high temperature plasmas and new sample introduction systems are explored for rapid elemental and isotopic analysis of gases, solutions, and solids using mass spectrometry and atomic emission spectrometry. Emphasis was placed on atmospheric pressure He inductively coupled plasmas (ICP) suitable for atomization, excitation, and ionization of elements; simulation and computer modeling of plasma sources with potential for use in spectrochemical analysis; spectroscopic imaging and diagnostic studies of high temperature plasmas, particularly He ICP discharges; and development of new, low-cost sample introduction systems, and examination of techniques for probing the aerosols over a wide range. Refs., 14 figs. (DLC)

  16. [Application of mass spectrometry in mycology].

    Science.gov (United States)

    Quiles Melero, Inmaculada; Peláez, Teresa; Rezusta López, Antonio; Garcia-Rodríguez, Julio

    2016-06-01

    MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight) mass spectrometry (MS) is becoming an essential tool in most microbiology laboratories. At present, by using a characteristic fungal profile obtained from whole cells or through simple extraction protocols, MALDI-TOF MS allows the identification of pathogenic fungi with a high performance potential. This methodology decreases the laboratory turnaround time, optimizing the detection of mycoses. This article describes the state-of-the-art of the use of MALDI-TOF MS for the detection of human clinical fungal pathogens in the laboratory and discusses the future applications of this technology, which will further improve routine mycological diagnosis. PMID:27389289

  17. Application of Nanodiamonds in Biomolecular Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Ping Cheng

    2010-03-01

    Full Text Available The combination of nanodiamond (ND with biomolecular mass spectrometry (MS makes rapid, sensitive detection of biopolymers from complex biosamples feasible. Due to its chemical inertness, optical transparency and biocompatibility, the advantage of NDs in MS study is unique. Furthermore, functionalization on the surfaces of NDs expands their application in the fields of proteomics and genomics for specific requirements greatly. This review presents methods of MS analysis based on solid phase extraction and elution on NDs and different application examples including peptide, protein, DNA, glycan and others. Owing to the quick development of nanotechnology, surface chemistry, new MS methods and the intense interest in proteomics and genomics, a huge increase of their applications in biomolecular MS analysis in the near future can be predicted.

  18. Mass spectrometry and Web 2.0.

    Science.gov (United States)

    Murray, Kermit K

    2007-10-01

    The term Web 2.0 is a convenient shorthand for a new era in the Internet in which users themselves are both generating and modifying existing web content. Several types of tools can be used. With social bookmarking, users assign a keyword to a web resource and the collection of the keyword 'tags' from multiple users form the classification of these resources. Blogs are a form of diary or news report published on the web in reverse chronological order and are a popular form of information sharing. A wiki is a website that can be edited using a web browser and can be used for collaborative creation of information on the site. This article is a tutorial that describes how these new ways of creating, modifying, and sharing information on the Web are being used for on-line mass spectrometry resources.

  19. Electrostatic-spray ionization mass spectrometry.

    Science.gov (United States)

    Qiao, Liang; Sartor, Romain; Gasilova, Natalia; Lu, Yu; Tobolkina, Elena; Liu, Baohong; Girault, Hubert H

    2012-09-01

    An electrostatic-spray ionization (ESTASI) method has been used for mass spectrometry (MS) analysis of samples deposited in or on an insulating substrate. The ionization is induced by a capacitive coupling between an electrode and the sample. In practice, a metallic electrode is placed close to but not in direct contact with the sample. Upon application of a high voltage pulse to the electrode, an electrostatic charging of the sample occurs leading to a bipolar spray pulse. When the voltage is positive, the bipolar spray pulse consists first of cations and then of anions. This method has been applied to a wide range of geometries to emit ions from samples in a silica capillary, in a disposable pipet tip, in a polymer microchannel, or from samples deposited as droplets on a polymer plate. Fractions from capillary electrophoresis were collected on a polymer plate for ESTASI MS analysis. PMID:22876737

  20. Radiocarbon dating with accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Radiocarbon dating by means of accelerator mass spectrometry (AMS) has two great advantages over conventional dating: 1) much smaller samples can be handled and 2) counting time is significantly shorter. Three examples are given for Holocene-age material from east-central Ellesmere Island. The results demonstrate the potential use of this technique as a powerful research tool in studies of Quaternary chronology. Individual fragments of marine shells as small as 0.1 g have been dated successfully at the IsoTrace Laboratory, University of Toronto. In the case of an aquatic moss from a lake sediment core, an increment 0.5 cm thick could be used instead of a 5 cm-thick slice, thus allowing a much more precise estimate of the onset of organic sedimentation

  1. China's food safety regulation and mass spectrometry.

    Science.gov (United States)

    Chu, Xiaogang; Zhang, Feng; Nie, Xuemei; Wang, Wenzhi; Feng, Feng

    2011-01-01

    Food safety is essential to people's health and people's livelihood. To ensure that food safety is an important current strategy of the governments, both regulation and standardization are important support for implementing this strategic initiative effectively. The status and prospects of China's food laws, regulations, and standards system are introduced. China now has established a complete law regime providing a sound foundation and good environment for keeping the health of people, maintaining the order of social economy and promoting the international trade of food. At the same time, it is undoubtedly important to strengthen standardization and improve the food safety standards system. In the administration of food safety, mass spectrometry is becoming more and more important and many analytical methods developed in China are based on its application. PMID:21643903

  2. Mass-spectrometric identification of primary biological particle markers and application to pristine submicron aerosol measurements in Amazonia

    Directory of Open Access Journals (Sweden)

    J. Schneider

    2011-11-01

    Full Text Available The detection of primary biological material in submicron aerosol by means of thermal desorption/electron impact ionization aerosol mass spectrometry was investigated. Mass spectra of amino acids, carbohydrates, small peptides, and proteins, all of which are key building blocks of biological particles, were recorded in laboratory experiments. Several characteristic marker fragments were identified. The intensity of the marker signals relative to the total organic mass spectrum allows for an estimation of the content of primary biological material in ambient organic aerosol. The developed method was applied to mass spectra recorded during AMAZE-08, a field campaign conducted in the pristine rainforest of the central Amazon Basin, Brazil, during the wet season of February and March 2008. The low abundance of identified marker fragments places upper limits of 7.5% for amino acids and 5.6% for carbohydrates on the contribution of primary biological aerosol particles (PBAP to the submicron organic aerosol mass concentration during this time period. Upper limits for the absolute submicron concentrations for both compound classes range from 0.01 to 0.1 μg m−3. Carbohydrates and proteins (composed of amino acids make up for about two thirds of the dry mass of a biological cell. Thus, our findings suggest an upper limit for the PBAP mass fraction of about 20% to the submicron organic aerosol measured in Amazonia during AMAZE-08.

  3. Mass spectrometry of acoustically levitated droplets.

    Science.gov (United States)

    Westphall, Michael S; Jorabchi, Kaveh; Smith, Lloyd M

    2008-08-01

    Containerless sample handling techniques such as acoustic levitation offer potential advantages for mass spectrometry, by eliminating surfaces where undesired adsorption/desorption processes can occur. In addition, they provide a unique opportunity to study fundamental aspects of the ionization process as well as phenomena occurring at the air-droplet interface. Realizing these advantages is contingent, however, upon being able to effectively interface levitated droplets with a mass spectrometer, a challenging task that is addressed in this report. We have employed a newly developed charge and matrix-assisted laser desorption/ionization (CALDI) technique to obtain mass spectra from a 5-microL acoustically levitated droplet containing peptides and an ionic matrix. A four-ring electrostatic lens is used in conjunction with a corona needle to produce bursts of corona ions and to direct those ions toward the droplet, resulting in droplet charging. Analyte ions are produced from the droplet by a 337-nm laser pulse and detected by an atmospheric sampling mass spectrometer. The ion generation and extraction cycle is repeated at 20 Hz, the maximum operating frequency of the laser employed. It is shown in delayed ion extraction experiments that both positive and negative ions are produced, behavior similar to that observed for atmospheric pressure matrix-assisted laser absorption/ionization. No ion signal is observed in the absence of droplet charging. It is likely, although not yet proven, that the role of the droplet charging is to increase the strength of the electric field at the surface of the droplet, reducing charge recombination after ion desorption. PMID:18582090

  4. Compressed sensing in imaging mass spectrometry

    International Nuclear Information System (INIS)

    Imaging mass spectrometry (IMS) is a technique of analytical chemistry for spatially resolved, label-free and multipurpose analysis of biological samples that is able to detect the spatial distribution of hundreds of molecules in one experiment. The hyperspectral IMS data is typically generated by a mass spectrometer analyzing the surface of the sample. In this paper, we propose a compressed sensing approach to IMS which potentially allows for faster data acquisition by collecting only a part of the pixels in the hyperspectral image and reconstructing the full image from this data. We present an integrative approach to perform both peak-picking spectra and denoising m/z-images simultaneously, whereas the state of the art data analysis methods solve these problems separately. We provide a proof of the robustness of the recovery of both the spectra and individual channels of the hyperspectral image and propose an algorithm to solve our optimization problem which is based on proximal mappings. The paper concludes with the numerical reconstruction results for an IMS dataset of a rat brain coronal section. (paper)

  5. From structure to function : Protein assemblies dissected by mass spectrometry

    NARCIS (Netherlands)

    Lorenzen, K.

    2008-01-01

    This thesis demonstrates some of the possibilities mass spectrometry can provide to gain new insight into structure and function of protein complexes. While technologies in native mass spectrometry are still under development, it already allows research on complete proteins and protein complexes up

  6. Structural analyses of sucrose laurate regioisomers by mass spectrometry techniques

    DEFF Research Database (Denmark)

    Lie, Aleksander; Stensballe, Allan; Pedersen, Lars Haastrup

    2015-01-01

    6- And 6′-O-lauroyl sucrose were isolated and analyzed by matrix-assisted laser desorption/ionisation (MALDI) time-of-flight (TOF) mass spectrometry (MS), Orbitrap high-resolution (HR) MS, and electrospray-ionization (ESI) tandem mass spectrometry (MS/MS). The analyses aimed to explore...

  7. HCN Polymers: Toward Structure Comprehension Using High Resolution Mass Spectrometry

    Science.gov (United States)

    Bonnet, Jean-Yves; Thissen, Roland; Frisari, Ma; Vuitton, Veronique; Quirico, Eric; Le Roy, Léna; Fray, Nicolas; Cottin, Hervé; Horst, Sarah; Yelle, Roger

    A lot of solar system materials, including cometary ices and Titan aerosols, contain dark matter that can be interpreted as complex nitrogen bearing organic matter [1]. In laboratory experi-ments, HCN polymers are thus analogs of great interest. In fact they may be present in Titan atmosphere and in comet nuclei and then reprocessed as a CN distributed source [2], when ices began to sublimate and ejects from the nucleus organic matter grains [3]. The presence of HCN polymers is suggested because HCN molecule has been directly observed in 1P/Halley comet [4] and others. HCN polymers are also of prebiotic interest [5] as it can form amino acid under hydrolysis conditions. Even if they have been studied during the last decades, their chemical composition and structure are still poorly understood, and a great analytical effort has to be continued. In this way we present a high resolution mass spectrometry (HRMS) and a high resolution tandem mass spectrometry (MS/HRMS) analysis of HCN polymers. It was shown [6] that this is a suitable technique to elucidate composition and structure of the soluble part of tholins analogs of Titan's atmosphere aerosols. HCN polymers have never been studied by HRMS, thus we used a LTQ-Orbitrap XL high resolution mass spectrometer to analyse the HCN polymers. These are produced at LISA by direct polymerisation of pure liquid HCN, catalyzed by ammonia. HCN polymers have been completely dissolved in methanol and then injected in the mass spectrometer by ElectroSpray Ionization (ESI). This atmospheric pressure ionization process produces protonated or deprotonated ions, but it does not fragment molecules. Thus HRMS, allows a direct access to the stoechiometry of all the ionizable molecules present in the samples. Fragmentation analyses (MS/MS) of selected ions have also been performed. Thess analysis provide information about the different chemical fonctionnalities present in HCN poly-mers and also about their structure. Thus we are able to

  8. Clinical Mass Spectrometry: Achieving Prominence in Laboratory Medicine

    Energy Technology Data Exchange (ETDEWEB)

    Annesley, Thomas M.; Cooks, Robert G.; Herold, David A.; Hoofnagle, Andrew N.

    2016-01-04

    Each year the journal Clinical Chemistry publishes a January special issue on a topic that is relevant to the laboratory medicine community. In January 2016 the topic is mass spectrometry, and the issue is entitled “Clinical Mass Spectrometry: Achieving Prominence in Laboratory Medicine”. One popular feature in our issues is a Q&A on a topic, clearly in this case mass spectrometry. The journal is assembling a panel of 5-6 experts from various areas of mass spectrometry ranging from instrument manufacturing to practicing clinical chemists. Dick Smith is one of the scientist requested to participate in this special issue Q&A on Mass Spectrometry. The Q&A Transcript is attached

  9. US Food and Drug Administration Perspectives on Clinical Mass Spectrometry.

    Science.gov (United States)

    Lathrop, Julia Tait; Jeffery, Douglas A; Shea, Yvonne R; Scholl, Peter F; Chan, Maria M

    2016-01-01

    Mass spectrometry-based in vitro diagnostic devices that measure proteins and peptides are underutilized in clinical practice, and none has been cleared or approved by the Food and Drug Administration (FDA) for marketing or for use in clinical trials. One way to increase their utilization is through enhanced interactions between the FDA and the clinical mass spectrometry community to improve the validation and regulatory review of these devices. As a reference point from which to develop these interactions, this article surveys the FDA's regulation of mass spectrometry-based devices, explains how the FDA uses guidance documents and standards in the review process, and describes the FDA's previous outreach to stakeholders. Here we also discuss how further communication and collaboration with the clinical mass spectrometry communities can identify opportunities for the FDA to provide help in the development of mass spectrometry-based devices and enhance their entry into the clinic. PMID:26553791

  10. Illustrating the Concepts of Isotopes and Mass Spectrometry in Introductory Courses: A MALDI-TOF Mass Spectrometry Laboratory Experiment

    Science.gov (United States)

    Dopke, Nancy Carter; Lovett, Timothy Neal

    2007-01-01

    Mass spectrometry is a widely used and versatile tool for scientists in many different fields. Soft ionization techniques such as matrix-assisted laser desorption/ionization (MALDI) allow for the analysis of biomolecules, polymers, and clusters. This article describes a MALDI mass spectrometry experiment designed for students in introductory…

  11. Identification of Unknown Contaminants in Water Samples from ISS Employing Liquid Chromatography/Mass Spectrometry/Mass Spectrometry

    Science.gov (United States)

    Rutz, Jeffrey A.; Schultz, John R.

    2008-01-01

    Mass Spectrometry/Mass Spectrometry (MS/MS) is a powerful technique for identifying unknown organic compounds. For non-volatile or thermally unstable unknowns dissolved in liquids, liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS) is often the variety of MS/MS used for the identification. One type of LC/MS/MS that is rapidly becoming popular is time-of-flight (TOF) mass spectrometry. This technique is now in use at the Johnson Space Center for identification of unknown nonvolatile organics in water samples from the space program. An example of the successful identification of one unknown is reviewed in detail in this paper. The advantages of time-of-flight instrumentation are demonstrated through this example as well as the strategy employed in using time-of-flight data to identify unknowns.

  12. Detection of Gunshot Residues Using Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Regina Verena Taudte

    2014-01-01

    Full Text Available In recent years, forensic scientists have become increasingly interested in the detection and interpretation of organic gunshot residues (OGSR due to the increasing use of lead- and heavy metal-free ammunition. This has also been prompted by the identification of gunshot residue- (GSR- like particles in environmental and occupational samples. Various techniques have been investigated for their ability to detect OGSR. Mass spectrometry (MS coupled to a chromatographic system is a powerful tool due to its high selectivity and sensitivity. Further, modern MS instruments can detect and identify a number of explosives and additives which may require different ionization techniques. Finally, MS has been applied to the analysis of both OGSR and inorganic gunshot residue (IGSR, although the “gold standard” for analysis is scanning electron microscopy with energy dispersive X-ray microscopy (SEM-EDX. This review presents an overview of the technical attributes of currently available MS and ionization techniques and their reported applications to GSR analysis.

  13. Secondary Ion Mass Spectrometry SIMS XI

    Science.gov (United States)

    Gillen, G.; Lareau, R.; Bennett, J.; Stevie, F.

    2003-05-01

    This volume contains 252 contributions presented as plenary, invited and contributed poster and oral presentations at the 11th International Conference on Secondary Ion Mass Spectrometry (SIMS XI) held at the Hilton Hotel, Walt Disney World Village, Orlando, Florida, 7 12 September, 1997. The book covers a diverse range of research, reflecting the rapid growth in advanced semiconductor characterization, ultra shallow depth profiling, TOF-SIMS and the new areas in which SIMS techniques are being used, for example in biological sciences and organic surface characterization. Papers are presented under the following categories: Isotopic SIMS Biological SIMS Semiconductor Characterization Techniques and Applications Ultra Shallow Depth Profiling Depth Profiling Fundamental/Modelling and Diffusion Sputter-Induced Topography Fundamentals of Molecular Desorption Organic Materials Practical TOF-SIMS Polyatomic Primary Ions Materials/Surface Analysis Postionization Instrumentation Geological SIMS Imaging Fundamentals of Sputtering Ion Formation and Cluster Formation Quantitative Analysis Environmental/Particle Characterization Related Techniques These proceedings provide an invaluable source of reference for both newcomers to the field and experienced SIMS users.

  14. Laser-induced electron capture mass spectrometry

    Science.gov (United States)

    Wang; Giese

    2000-02-15

    Two techniques are reported for detection of electrophorederivatized compounds by laser-induced electron capture time-of-flight mass spectrometry (LI-EC-TOF-MS). In both cases, a nitrogen laser is used to induce the electron capture. The analyte is deposited in a matrix consisting of a compound with a low ionization potential such as benzo[ghi]perylene in the first technique, where the electron for electron capture apparently comes from this matrix. In the second technique, the analyte is deposited on a silver surface in the absence of matrix. It seems that "monoenergetic" ions instantly desorb from the target surface in the latter case, since the peak width in the continuous extraction mode essentially matches the pulse width of the laser (4 ns). Ten picomoles of 3-O-(pentafluorobenzyl)-alpha-estradiol were detected at a S/N > or = 50, where the spot size of the laser was approximately 0.25% of the sample spot. It is attractive that simple conditions can enable sensitive detection of electrophores on routine TOF-MS equipment. The technique can be anticipated to broaden the range of analytes in both polarity and size that can be detected by EC-MS relative to the range for GC/EC-MS. PMID:10701262

  15. Isotopic Measurement of Uranium by Mass Spectrometry

    International Nuclear Information System (INIS)

    The growing application of atomic energy creates a wider need for precise and accurate knowledge of the isotopic composition of uranium. This information is particularly of great importance in the accountability and transfer of enriched uranium for reactor and research applications involving millions of dollars worth of fissionable materials. Reliable isotopic measurements are also necessary to ensure compliance of fuel element compositions with the reactor design specifications and to permit calculation of process and fuel burn-up losses. Mass spectrometry methods, which far surpass the capabilities of other methods, Were developed for very precise isotopic determinations. These methods, ''Single Standard'' and ''Double Standard'', involve the comparison of measurements of an unknown sample to similar measurements on known standards. Use of the ''Double Standard'' method eliminates the effects of instrument bias, thus permitting isotopic determinations with precisions (95% limit of error) of the order of ± 0.02% of the values. Accuracies are limited only by the knowledge of the standard values used, which are referenced to the series of uranium isotopic standards available from the US National Bureau of Standards. The mass spectrometers are also useful for the absolute determination of isotopic composition of uranium, especially in forms other than UF6. Thermal ionization techniques using high-resolution (approximately 12-in. radius) spectrometers permit the absolute isotopic characterization of the minor isotopes (i.e. those less than 10 wt.%) with an accuracy and precision of about 0.5% of the values per analysis. These analyses are particularly useful in calibrating highly enriched and highly depleted uranium for subsequent use as blending materials in an isotopic standards programme. Both relative and absolute isotopic measurement methods are described as well as their application in the accountability and operational analytical programmes. These applications

  16. Interpretation of Tandem Mass Spectrometry (MSMS) Spectra for Peptide Analysis

    DEFF Research Database (Denmark)

    Hjernø, Karin; Højrup, Peter

    2015-01-01

    The aim of this chapter is to give a short introduction to peptide analysis by mass spectrometry (MS) and interpretation of fragment mass spectra. Through examples and guidelines we demonstrate how to understand and validate search results and how to perform de novo sequencing based on the often...... very complex fragmentation pattern obtained by tandem mass spectrometry (also referred to as MSMS). The focus is on simple rules for interpretation of MSMS spectra of tryptic as well as non-tryptic peptides....

  17. Enhanced Volatile Organic Compounds emissions and organic aerosol mass increase the oligomer content of atmospheric aerosols

    Science.gov (United States)

    Kourtchev, Ivan; Giorio, Chiara; Manninen, Antti; Wilson, Eoin; Mahon, Brendan; Aalto, Juho; Kajos, Maija; Venables, Dean; Ruuskanen, Taina; Levula, Janne; Loponen, Matti; Connors, Sarah; Harris, Neil; Zhao, Defeng; Kiendler-Scharr, Astrid; Mentel, Thomas; Rudich, Yinon; Hallquist, Mattias; Doussin, Jean-Francois; Maenhaut, Willy; Bäck, Jaana; Petäjä, Tuukka; Wenger, John; Kulmala, Markku; Kalberer, Markus

    2016-10-01

    Secondary organic aerosol (SOA) accounts for a dominant fraction of the submicron atmospheric particle mass, but knowledge of the formation, composition and climate effects of SOA is incomplete and limits our understanding of overall aerosol effects in the atmosphere. Organic oligomers were discovered as dominant components in SOA over a decade ago in laboratory experiments and have since been proposed to play a dominant role in many aerosol processes. However, it remains unclear whether oligomers are relevant under ambient atmospheric conditions because they are often not clearly observed in field samples. Here we resolve this long-standing discrepancy by showing that elevated SOA mass is one of the key drivers of oligomer formation in the ambient atmosphere and laboratory experiments. We show for the first time that a specific organic compound class in aerosols, oligomers, is strongly correlated with cloud condensation nuclei (CCN) activities of SOA particles. These findings might have important implications for future climate scenarios where increased temperatures cause higher biogenic volatile organic compound (VOC) emissions, which in turn lead to higher SOA mass formation and significant changes in SOA composition. Such processes would need to be considered in climate models for a realistic representation of future aerosol-climate-biosphere feedbacks.

  18. Mass spectrometry for characterizing plant cell wall polysaccharides

    Directory of Open Access Journals (Sweden)

    Stefan eBauer

    2012-03-01

    Full Text Available Mass spectrometry is a selective and powerful technique to obtain identification and structural information on compounds present in complex mixtures. Since it requires only small sample amount it is an excellent tool for researchers interested in detecting changes in composition of complex carbohydrates of plants. This mini-review gives an overview of common mass spectrometry techniques applied to the analysis of plant cell wall carbohydrates. It presents examples in which mass spectrometry has been used to elucidate the structure of oligosaccharides derived from hemicelluloses and pectins and illustrates how information on sequence, linkages, branching and modifications are obtained from characteristic fragmentation patterns.

  19. A Review on Mass Spectrometry: Technique and Tools

    Directory of Open Access Journals (Sweden)

    Ms. Ashwini Yerlekar

    2014-04-01

    Full Text Available Protein structure prediction has gain important in area of life sciences, because of its complex structure. The protein-protein interaction is necessary to study the behavior of protein in a specific environment, and study molecular relationship in living systems. Therefore, large scale proteomics technologies are required to measure physical connection of proteins in living organisms. Mass Spectrometry uses the technique to measure mass-to-charge ratio of ion. It's an evolving technique for characterization of proteins. A Mass Spectrometer can be more sensitive and specific, also complement with other LC detectors. Liquid Chromatography, unlike gas chromatography is a separation technique which helps to separate wide range of organic compounds from small molecular metabolites to peptides and proteins. This paper addresses the study of data analysis using mass Spectrometry. It also includes the study of various methods of Mass Spectrometry data analysis, the tools and various applications of Mass Spectrometry.This review briefs on Mass Spectrometry technique, its application, usage, and tools used by Mass Spectrometry

  20. Advanced Mass Calibration and Visualization for FT-ICR Mass Spectrometry Imaging

    OpenAIRE

    Smith, Donald F.; Kharchenko, Andriy; Konijnenburg, Marco; Klinkert, Ivo; Pasa-Tolic, Ljiljana; Ron M A Heeren

    2013-01-01

    Mass spectrometry imaging by Fourier transform ion cyclotron resonance yields hundreds of unique peaks, many of which cannot be resolved by lower performance mass spectrometers. The high mass accuracy and high mass resolving power allow confident identification of small molecules and lipids directly from biological tissue sections. Here, calibration strategies for Fourier transform ion cyclotron resonance mass spectrometry imaging were investigated. Sub parts-per-million mass accuracy is demo...

  1. A novel isotope analysis of oxygen in uranium oxides: comparison of secondary ion mass spectrometry, glow discharge mass spectrometry and thermal ionization mass spectrometry

    Science.gov (United States)

    Pajo, L.; Tamborini, G.; Rasmussen, G.; Mayer, K.; Koch, L.

    2001-05-01

    The natural variation of the oxygen isotopic composition is used among geologists to determine paleotemperatures and the origin of minerals. In recent studies, oxygen isotopic composition has been recognized as a possible tool for identification of the origin of seized uranium oxides in nuclear forensic science. In the last 10 years, great effort has been made to develop new direct and accurate n( 18O)/ n( 16O) measurements methods. Traditionally, n( 18O)/ n( 16O) analyses are performed by gas mass spectrometry. In this work, a novel oxygen isotope analysis by thermal ionization mass spectrometry (TIMS), using metal oxide ion species (UO +), is compared to the direct methods: glow discharge mass spectrometry (GDMS) and secondary ion mass spectrometry (SIMS). Because of the possible application of the n( 18O)/ n( 16O) ratio in nuclear forensics science, the samples were solid, pure UO 2 or U 3O 8 particles. The precision achieved using TIMS analysis was 0.04%, which is similar or even better than the one obtained using the SIMS technique (0.05%), and clearly better if compared to that of GDMS (0.5%). The samples used by TIMS are micrograms in size. The suitability of TIMS as a n( 18O)/ n( 16O) measurement method is verified by SIMS measurements. In addition, TIMS results have been confirmed by characterizing the n( 18O)/ n( 16O) ratio of UO 2 sample also by the traditional method of static vacuum mass spectrometry at the University of Chicago.

  2. Identifying modifications in RNA by MALDI mass spectrometry

    DEFF Research Database (Denmark)

    Douthwaite, Stephen; Kirpekar, Finn

    2007-01-01

    Posttranscriptional modifications on the base or sugar of ribonucleosides generally result in mass increases that can be measured by mass spectrometry. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a direct and accurate means of determining the masses of RNAs. Mass s...... in fundamental processes in protein synthesis as well as methylations that confer resistance to antibiotics. For several rRNA sites, MALDI-MS has served an essential role in the identification of the enzymes that catalyze the modifications....

  3. Ambient mass spectrometry imaging: plasma assisted laser desorption ionization mass spectrometry imaging and its applications.

    Science.gov (United States)

    Feng, Baosheng; Zhang, Jialing; Chang, Cuilan; Li, Liping; Li, Min; Xiong, Xingchuang; Guo, Chengan; Tang, Fei; Bai, Yu; Liu, Huwei

    2014-05-01

    Mass spectrometry imaging (MSI) has been widely used in many research areas for the advantages of providing informative molecular distribution with high specificity. Among the recent progress, ambient MSI has attracted increasing interests owing to its characteristics of ambient, in situ, and nonpretreatment analysis. Here, we are presenting the ambient MSI for traditional Chinese medicines (TCMs) and authentication of work of art and documents using plasma assisted laser desorption ionization mass spectrometry (PALDI-MS). Compared with current ambient MSI methods, an excellent average resolution of 60 μm × 60 μm pixel size was achieved using this system. The feasibility of PALDI-based MSI was confirmed by seal imaging, and its authentication applications were demonstrated by imaging of printed Chinese characters. Imaging of the Radix Scutellariae slice showed that the two active components, baicalein and wogonin, mainly were distributed in the epidermis of the root, which proposed an approach for distinguishing TCMs' origins and the distribution of active components of TCMs and exploring the environmental effects of plant growth. PALDI-MS imaging provides a strong complement for the MSI strategy with the enhanced spatial resolution, which is promising in many research fields, such as artwork identification, TCMs' and botanic research, pharmaceutical applications, etc. PMID:24670045

  4. Quantification of hydroxyacetone and glycolaldehyde using chemical ionization mass spectrometry

    Directory of Open Access Journals (Sweden)

    K. M. Spencer

    2011-08-01

    Full Text Available Chemical ionization mass spectrometry (CIMS enables online, fast, in situ detection and quantification of hydroxyacetone and glycolaldehyde. Two different CIMS approaches are demonstrated employing the strengths of single quadrupole mass spectrometry and triple quadrupole (tandem mass spectrometry. Both methods are capable of the measurement of hydroxyacetone, an analyte with minimal isobaric interferences. Tandem mass spectrometry provides direct separation of the isobaric compounds glycolaldehyde and acetic acid using distinct, collision-induced dissociation daughter ions. Measurement of hydroxyacetone and glycolaldehyde by these methods was demonstrated during the ARCTAS-CARB 2008 campaign and the BEARPEX 2009 campaign. Enhancement ratios of these compounds in ambient biomass burning plumes are reported for the ARCTAS-CARB campaign. BEARPEX observations are compared to simple photochemical box model predictions of biogenic volatile organic compound oxidation at the site.

  5. The use of elemental mass spectrometry in phosphoproteomic applications.

    Science.gov (United States)

    Maes, Evelyne; Tirez, Kristof; Baggerman, Geert; Valkenborg, Dirk; Schoofs, Liliane; Encinar, Jorge Ruiz; Mertens, Inge

    2016-01-01

    Reversible phosphorylation is one of the most important post-translational modifications in mammalian cells. Because this molecular switch is an important mechanism that diversifies and regulates proteins in cellular processes, knowledge about the extent and quantity of phosphorylation is very important to understand the complex cellular interplay. Although phosphoproteomics strategies are applied worldwide, they mainly include only molecular mass spectrometry (like MALDI or ESI)-based experiments. Although identification and relative quantification of phosphopeptides is straightforward with these techniques, absolute quantification is more complex and usually requires for specific isotopically phosphopeptide standards. However, the use of elemental mass spectrometry, and in particular inductively coupled plasma mass spectrometry (ICP-MS), in phosphoproteomics-based experiments, allow one to absolutely quantify phosphopeptides. Here, these phosphoproteomic applications with ICP-MS as elemental detector are reviewed. Pioneering work and recent developments in the field are both described. Additionally, the advantage of the parallel use of molecular and elemental mass spectrometry is stressed. PMID:25139451

  6. Accelerator mass spectrometry programme at Mumbai pelletron accelerator facility

    International Nuclear Information System (INIS)

    The Accelerator Mass Spectrometry (AMS) programme and the related developments based on the Mumbai Pelletron accelerator are described. The initial results of the measurement of the ratio, 36Cl / Cl in water samples are presented. (author)

  7. Laser mass spectrometry for DNA sequencing, disease diagnosis, and fingerprinting

    Energy Technology Data Exchange (ETDEWEB)

    Winston Chen, C.H.; Taranenko, N.I.; Zhu, Y.F.; Chung, C.N.; Allman, S.L.

    1997-03-01

    Since laser mass spectrometry has the potential for achieving very fast DNA analysis, the authors recently applied it to DNA sequencing, DNA typing for fingerprinting, and DNA screening for disease diagnosis. Two different approaches for sequencing DNA have been successfully demonstrated. One is to sequence DNA with DNA ladders produced from Snager`s enzymatic method. The other is to do direct sequencing without DNA ladders. The need for quick DNA typing for identification purposes is critical for forensic application. The preliminary results indicate laser mass spectrometry can possibly be used for rapid DNA fingerprinting applications at a much lower cost than gel electrophoresis. Population screening for certain genetic disease can be a very efficient step to reducing medical costs through prevention. Since laser mass spectrometry can provide very fast DNA analysis, the authors applied laser mass spectrometry to disease diagnosis. Clinical samples with both base deletion and point mutation have been tested with complete success.

  8. 13th International Mass Spectrometry Conference. Book of Abstracts

    International Nuclear Information System (INIS)

    The collection contains abstracts of several hundred papers presented at the international conference on new research and development results and applications of mass spectrometry. Abstracts falling into the INIS scope were indexed separately in the INIS database. (Roboz, P.)

  9. THE APPLICATION OF MASS SPECTROMETRY TO THE STUDY OF MICROORGANISMS

    Science.gov (United States)

    The purpose of this research project is to use state-of-the-art mass spectrometric techniques, such as electrospray ionization (ESI) and matrix assisted laser desorption ionization (MALDI) mass spectrometry (MS), to provide "protein mass fingerprinting" and protein sequencing i...

  10. Desorption electrospray ionization-mass spectrometry of proteins

    Science.gov (United States)

    Desorption electrospray ionization-mass spectrometry (DESI-MS) was evaluated for the detection of proteins ranging in molecular mass from 12 to 66 kDa. Proteins were uniformly deposited on a solid surface without pretreatment and analyzed with a DESI source coupled to a quadrupole ion trap mass spec...

  11. Aerosol quantification with the Aerodyne Aerosol Mass Spectrometer: detection limits and ionizer background effects

    Directory of Open Access Journals (Sweden)

    S. Borrmann

    2009-02-01

    Full Text Available Systematic laboratory experiments were performed to investigate quantification of various species with two versions of the Aerodyne Aerosol Mass Spectrometer, a Quadrupole Aerosol Mass Spectrometer (Q-AMS and a compact Time-of-Flight Aerosol Mass Spectrometer (c-ToF-AMS. Here we present a new method to continuously determine the detection limits of the AMS analyzers during regular measurements, yielding detection limit (DL information under various measurement conditions. Minimum detection limits range from 0.03 μg m−3 (nitrate, sulfate, and chloride up to 0.5 μg m−3 (organics for the Q-AMS. Those of the c-ToF-AMS are found between 0.003 μg m−3 (nitrate, sulfate and 0.03 μg m−3 (ammonium, organics. The DL values found for the c-ToF-AMS were ~10 times lower than those of the Q-AMS, mainly due to differences in ion duty cycle. Effects causing an increase of the detection limits include long-term instrument contamination, measurement of high aerosol mass concentrations and short-term instrument history. The self-cleaning processes which reduce the instrument background after measurement of large aerosol concentrations as well as the influences of increased instrument background on mass concentration measurements are discussed. Finally, improvement of detection limits by extension of averaging time intervals, selected or reduced ion monitoring, and variation of particle-to-background measurement ratio are investigated.

  12. Subcellular analysis by laser ablation electrospray ionization mass spectrometry

    Science.gov (United States)

    Vertes, Akos; Stolee, Jessica A; Shrestha, Bindesh

    2014-12-02

    In various embodiments, a method of laser ablation electrospray ionization mass spectrometry (LAESI-MS) may generally comprise micro-dissecting a cell comprising at least one of a cell wall and a cell membrane to expose at least one subcellular component therein, ablating the at least one subcellular component by an infrared laser pulse to form an ablation plume, intercepting the ablation plume by an electrospray plume to form ions, and detecting the ions by mass spectrometry.

  13. Determination of nitrofuran and chloramphenicol residues by high resolution mass spectrometry versus tandem quadrupole mass spectrometry.

    Science.gov (United States)

    Kaufmann, A; Butcher, P; Maden, K; Walker, S; Widmer, M

    2015-03-01

    An ultra-high performance liquid chromatography based method, coupled to high resolution mass spectrometry (UHPLC-HRMS), was developed to permit the detection and quantification of various nitrofuran and chloramphenicol residues in a number of animal based food products. This method is based on the hydrolysis of covalently bound metabolites and derivatization with 2-nitrobenzaldehyde. Clean-up is achieved by a liquid/liquid and a reversed phase/solid phase extraction. Not only are the four conventional nitrofurans (nitrofurantoin, furazolidone, nitrofurazone and furaltadone) detected, but also nifursol, nitrovin and nifuroxazide. Furthermore, an underivatizable nitrofuran (nifurpirinol) and another banned drug (chloramphenicol) can be quantified as well. The compounds are detected in the form of their precursor ions, [M+H](+) and [M-H](-), respectively. The mass resolving power of 70,000 FWHM, and the applied mass window ensure sufficient selectivity and sensitivity. Confirmation is obtained by monitoring the HRMS resolved product ions which were derived from the unit-mass resolved precursor ions. The multiplexing capability of the utilized Orbitrap instrument provides not only highly selective, but also sensitive confirmatory signals. This method has been validated according to the CD 2002/657/EC for the following matrices: muscle, liver, kidney, fish, honey, eggs and milk. PMID:25682427

  14. Elemental mass size distribution of the Debrecen urban aerosol

    International Nuclear Information System (INIS)

    Complete text of publication follows. Size distribution is one of the basic properties of atmospheric aerosol. It is closely related to the origin, chemical composition and age of the aerosol particles, and it influences the optical properties, environmental effects and health impact of aerosol. As part of the ongoing aerosol research in the Group of Ion Beam Applications of the Atomki, elemental mass size distribution of urban aerosol were determined using particle induced X-ray emission (PIXE) analytical technique. Aerosol sampling campaigns were carried out with 9-stage PIXE International cascade impactors, which separates the aerosol into 10 size fractions in the 0.05-30 ?m range. Five 48-hours long samplings were done in the garden of the Atomki, in April and in October, 2007. Both campaigns included weekend and working day samplings. Basically two different kinds of particles could be identified according to the size distribution. In the size distribution of Al, Si, Ca, Fe, Ba, Ti, Mn and Co one dominant peak can be found around the 3 m aerodynamic diameter size range, as it is shown on Figure 1. These are the elements of predominantly natural origin. Elements like S, Cl, K, Zn, Pb and Br appears with high frequency in the 0.25-0.5 mm size range as presented in Figure 2. These elements are originated mainly from anthropogenic sources. However sometimes in the size distribution of these elements a 2nd, smaller peak appears at the 2-4 μm size ranges, indicating different sources. Differences were found between the size distribution of the spring and autumn samples. In the case of elements of soil origin the size distribution was shifted towards smaller diameters during October, and a 2nd peak appeared around 0.5 μm. A possible explanation to this phenomenon can be the different meteorological conditions. No differences were found between the weekend and working days in the size distribution, however the concentration values were smaller during the weekend

  15. Direct gravimetric determination of aerosol mass concentration in central antarctica.

    Science.gov (United States)

    Annibaldi, Anna; Truzzi, Cristina; Illuminati, Silvia; Scarponi, Giuseppe

    2011-01-01

    In Antarctica, experimental difficulties due to extreme conditions have meant that aerosol mass has rarely been measured directly by gravimetry, and only in coastal areas where concentrations were in the range of 1-7 μg m(-3). The present work reports on a careful differential weighing methodology carried out for the first time on the plateau of central Antarctica (Dome C, East Antarctica). To solve problems of accurate aerosol mass measurements, a climatic room was used for conditioning and weighing filters. Measurements were carried out in long stages of several hours of readings with automatic recording of temperature/humidity and mass. This experimental scheme allowed us to sample from all the measurements (up to 2000) carried out before and after exposure, those which were recorded under the most stable humidity conditions and, even more importantly, as close to each other as possible. The automatic reading of the mass allowed us in any case to obtain hundreds of measurements from which to calculate average values with uncertainties sufficiently low to meet the requirements of the differential weighing procedure (±0.2 mg in filter weighing, between ±7% and ±16% both in aerosol mass and concentration measurements). The results show that the average summer aerosol mass concentration (aerodynamic size ≤10 μm) in central Antarctica is about 0.1 μg m(-3), i.e., about 1/10 of that of coastal Antarctic areas. The concentration increases by about 4-5 times at a site very close to the station. PMID:21141836

  16. Analysis of posttranslational modifications of proteins by tandem mass spectrometry

    DEFF Research Database (Denmark)

    Larsen, Martin Røssel; Trelle, Morten B; Thingholm, Tine E;

    2006-01-01

    -temporal distribution in cells and tissues. Most PTMs can be detected by protein and peptide analysis by mass spectrometry (MS), either as a mass increment or a mass deficit relative to the nascent unmodified protein. Tandem mass spectrometry (MS/MS) provides a series of analytical features that are highly useful for......Protein activity and turnover is tightly and dynamically regulated in living cells. Whereas the three-dimensional protein structure is predominantly determined by the amino acid sequence, posttranslational modification (PTM) of proteins modulates their molecular function and the spatial...

  17. Secondary Ion Mass Spectrometry Imaging of Dictyostelium discoideum Aggregation Streams

    Energy Technology Data Exchange (ETDEWEB)

    Debord, J. Daniel; Smith, Donald F.; Anderton, Christopher R.; Heeren, Ronald M.; Pasa-Tolic, Ljiljana; Gomer, Richard H.; Fernandez-Lima, Francisco A.

    2014-06-09

    High resolution imaging mass spectrometry could become a valuable tool for cell and developmental biology, but both, high spatial and mass spectral resolution are needed to enable this. In this report, we employed Bi3 bombardment time-of-flight (Bi3 ToF-SIMS) and C60 bombardment Fourier transform ion cyclotron resonance secondary ion mass spectrometry (C60 FTICR-SIMS) to image Dictyostelium discoideum aggregation streams. Nearly 300 lipid species were identified from the aggregation streams. High resolution mass spectrometry imaging (FTICR-SIMS) enabled the generation of multiple molecular ion maps at the nominal mass level and provided good coverage for fatty acyls, prenol lipids, and sterol lipids. The comparison of Bi3 ToF-SIMS and C60 FTICR-SIMS suggested that while the first provides fast, high spatial resolution molecular ion images, the chemical complexity of biological samples warrants the use of high resolution analyzers for accurate ion identification.

  18. Proteomics and Mass Spectrometry for Cancer Biomarker Discovery

    Directory of Open Access Journals (Sweden)

    Ming Lu

    2007-01-01

    Full Text Available Proteomics is a rapidly advancing field not only in the field of biology but also in translational cancer research. In recent years, mass spectrometry and associated technologies have been explored to identify proteins or a set of proteins specific to a given disease, for the purpose of disease detection and diagnosis. Such biomarkers are being investigated in samples including cells, tissues, serum/plasma, and other types of body fluids. When sufficiently refined, proteomic technologies may pave the way for early detection of cancer or individualized therapy for cancer. Mass spectrometry approaches coupled with bioinformatic tools are being developed for biomarker discovery and validation. Understanding basic concepts and application of such technology by investigators in the field may accelerate the clinical application of protein biomarkers in disease management.Abbreviations: 2DE: two-dimensional gel electrophoresis; ABPP: activity-based protein profiling; CEA: carcinoembryonic antigen; CI: confidence interval; ESI: electrospray ionization; FP: fluorophosphonate; HPLC: high performance liquid chromatography; ICAT: isotope coded affi nitytags; IEF: isoelectric focusing; iTRAQ: isobaric tags for relative and absolute quantification; LCMS: combined liquid chromatography-mass spectrometry; LCMSMS: liquid chromatography tandem mass spectrometry; LOD: limit of detection; m/z: mass to charge ratio; MALDI: matrix-assisted laser desorption ionization; MS: mass spectrometry; MUDPIT: multidimensional protein identification technology; NAF: nipple aspirate fluid; PMF: peptide mass fingerprinting; PSA: prostate specifi c antigen; PTMs: post-translational modifications; RPMA: reverse phase protein microarray; SELDI: surface enhanced laser desorption ionization; TOF: time-of-flight.

  19. Atmospheric pressure flow reactor / aerosol mass spectrometer studies of tropospheric aerosol nucleat and growth kinetics. Final report, June, 2001

    Energy Technology Data Exchange (ETDEWEB)

    Worsnop, Douglas R.

    2001-06-01

    The objective of this program was to determine the mechanisms and rates of growth and transformation and growth processes that control secondary aerosol particles in both the clear and polluted troposphere. The experimental plan coupled an aerosol mass spectrometer (AMS) with a chemical ionization mass spectrometer to provide simultaneous measurement of condensed and particle phases. The first task investigated the kinetics of tropospheric particle growth and transformation by measuring vapor accretion to particles (uptake coefficients, including mass accommodation coefficients and heterogeneous reaction rate coefficients). Other work initiated investigation of aerosol nucleation processes by monitoring the appearance of submicron particles with the AMS as a function of precursor gas concentrations. Three projects were investigated during the program: (1) Ozonolysis of oleic acid aerosols as model of chemical reactivity of secondary organic aerosol; (2) Activation of soot particles by measurement deliquescence in the presence of sulfuric acid and water vapor; (3) Controlled nucleation and growth of sulfuric acid aerosols.

  20. Incorporating Biological Mass Spectrometry into Undergraduate Teaching Labs, Part 2: Peptide Identification via Molecular Mass Determination

    Science.gov (United States)

    Arnquist, Isaac J.; Beussman, Douglas J.

    2009-01-01

    Mass spectrometry has become a routine analytical tool in the undergraduate curriculum in the form of GC-MS. While relatively few undergraduate programs have incorporated biological mass spectrometry into their programs, the importance of these techniques, as demonstrated by their recognition with the 2002 Nobel Prize, will hopefully lead to…

  1. Desorption electrospray ionization mass spectrometry of intact bacteria

    Science.gov (United States)

    Desorption electrospray ionization (DESI) mass spectrometry (MS) was used to differentiate 7 bacterial species based on their measured DESI-mass spectral profile. Both Gram positive and Gram negative bacteria were tested and included Escherichia coli, Staphyloccocus aureus, Enterococcus sp., Bordete...

  2. Electrospray ionization combined with ion trap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Van Berkel, G.J.; Glish, G.L.; McLuckey, S.A. (Oak Ridge National Laboratory, TN (USA))

    1990-07-01

    Ions from a variety of molecules, formed via electrospray, have been injected into and analyzed with a quadrupole ion trap mass spectrometer. Examples are shown in which one or more stages of mass spectrometry (e.g., mass spectrometry/mass spectrometry) have been performed on both multiply charged anions and cations. Compounds for which data are described include the disodium salt of 2-hydroxynapthalene-3,6-disulfonic acid, Direct Red 81, bradykinin, melittin, cytochrome c, myoglobin, and bovine albumin. For some compounds, notable the sulfonates, evidence is presented for the injection of highly solvated ions that desolvate within the ion trap. The cations derived from the peptides, on the other hand, appear to be essentially desolvated prior to injection into the ion trap.

  3. Use of mass spectrometry for imaging metabolites in plants

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young-Jin; Perdian, David; Song, Zhihong; Yeung, Edward; Nikolau, Basil

    2012-03-27

    We discuss and illustrate recent advances that have been made to image the distribution of metabolites among cells and tissues of plants using different mass spectrometry technologies. These technologies include matrix-assisted laser desorption ionization, desorption electrospray ionization, and secondary ion mass spectrometry. These are relatively new technological applications of mass spectrometry and they are providing highly spatially resolved data concerning the cellular distribution of metabolites. We discuss the advantages and limitations of each of these mass spectrometric methods, and provide a description of the technical barriers that are currently limiting the technology to the level of single-cell resolution. However, we anticipate that advances in the next few years will increase the resolving power of the technology to provide unprecedented data on the distribution of metabolites at the subcellular level, which will increase our ability to decipher new knowledge concerning the spatial organization of metabolic processes in plants.

  4. Applications of Mass Spectrometry to Structural Analysis of Marine Oligosaccharides

    Directory of Open Access Journals (Sweden)

    Yinzhi Lang

    2014-06-01

    Full Text Available Marine oligosaccharides have attracted increasing attention recently in developing potential drugs and biomaterials for their particular physical and chemical properties. However, the composition and sequence analysis of marine oligosaccharides are very challenging for their structural complexity and heterogeneity. Mass spectrometry (MS has become an important technique for carbohydrate analysis by providing more detailed structural information, including molecular mass, sugar constituent, sequence, inter-residue linkage position and substitution pattern. This paper provides an overview of the structural analysis based on MS approaches in marine oligosaccharides, which are derived from some biologically important marine polysaccharides, including agaran, carrageenan, alginate, sulfated fucan, chitosan, glycosaminoglycan (GAG and GAG-like polysaccharides. Applications of electrospray ionization mass spectrometry (ESI-MS are mainly presented and the general applications of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS are also outlined. Some technical challenges in the structural analysis of marine oligosaccharides by MS have also been pointed out.

  5. Use of Mass spectrometry for imaging metabolites in plants

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Jin; Perdian, David C.; Song, Zhihong; Yeung, Edward S.; Nikolau, Basil

    2012-03-27

    We discuss and illustrate recent advances that have been made to image the distribution of metabolites among cells and tissues of plants using different mass spectrometry technologies. These technologies include matrix-assisted laser desorption ionization, desorption electrospray ionization, and secondary ion mass spectrometry. These are relatively new technological applications of mass spectrometry and they are providing highly spatially resolved data concerning the cellular distribution of metabolites. We discuss the advantages and limitations of each of these mass spectrometric methods, and provide a description of the technical barriers that are currently limiting the technology to the level of single-cell resolution. However, we anticipate that advances in the next few years will increase the resolving power of the technology to provide unprecedented data on the distribution of metabolites at the subcellular level, which will increase our ability to decipher new knowledge concerning the spatial organization of metabolic processes in plants.

  6. Liquid sample introduction in inductively coupled plasma atomic emission and mass spectrometry — Critical review

    International Nuclear Information System (INIS)

    Inductively coupled plasma optical emission spectroscopy (ICP-OES) and mass spectrometry (ICP-MS) can be considered as the most important tools in inorganic analytical chemistry. Huge progress has been made since the first analytical applications of the ICP. More stable RF generators, improved spectrometers and detection systems were designed along with the achievements gained from advanced microelectronics, leading to overall greatly improved analytical performance of such instruments. In contrast, for the vast majority of cases liquid sample introduction is still based on the pneumatic principle as described in the late 19th century. High flow pneumatic nebulizers typically demand the use of spray chambers as “aerosol filters” in order to match the prerequisites of an ICP. By this, only a small fraction of the nebulized sample actually contributes to the measured signal. Hence, the development of micronebulizers was brought forward. Those systems produce fine aerosols at low sample uptake rates, but they are even more prone for blocking or clogging than conventional systems in the case of solutions containing a significant amount of total dissolved solids (TDS). Despite the high number of publications devoted to liquid sample introduction, it is still considered the Achilles' heel of atomic spectrometry and it is well accepted, that the technology used for liquid sample introduction is still far from ideal, even when applying state-of-the-art systems. Therefore, this review is devoted to offer an update on developments in the field liquid sample introduction that had been reported until the year 2013. The most recent and noteworthy contributions to this field are discussed, trends are highlighted and future directions are outlined. The first part of this review provides a brief overview on theoretical considerations regarding conventional pneumatic nebulization, the fundamentals on aerosol generation and discusses characteristics of aerosols ideally

  7. Aerosol quantification with the Aerodyne Aerosol Mass Spectrometer: detection limits and ionizer background effects

    Directory of Open Access Journals (Sweden)

    F. Drewnick

    2008-10-01

    Full Text Available Systematic laboratory experiments were performed to investigate quantification of various species with two versions of the Aerodyne Aerosol Mass Spectrometer, a Q-AMS and a c-ToF-AMS. Here we present a new method to continuously determine the detection limits of the AMS analyzers during regular measurements, yielding DL information under various measurement conditions. Minimum detection limits range from 0.03 μg m−3 (nitrate, sulfate, and chloride up to 0.5 μg m−3 (organics for the Q-AMS. Those of the c-ToF-AMS are found between 0.003 μg m−3 (nitrate, sulfate and 0.03 μg m−3 (ammonium, organics. The DL values found for the c-ToF-AMS were ~10 times lower than those of the Q-AMS, mainly due to differences in ion duty cycle. Effects causing an increase of the detection limits include long-term instrument contamination, measurement of high aerosol mass concentrations and short-term instrument history. The self-cleaning processes which reduce the instrument background after measurement of large aerosol concentrations as well as the influences of increased instrument background on mass concentration measurements are discussed. Finally, improvement of detection limits by extension of averaging time intervals, selected or reduced ion monitoring, and variation of particle-to-background measurement ratio are investigated.

  8. Ambient Aerosol in Southeast Asia: High Resolution Aerosol Mass Spectrometer Measurements Over Oil Palm (Elaeis guineensis)

    Science.gov (United States)

    Phillips, G.; Dimarco, C.; Misztal, P.; Nemitz, E.; Farmer, D.; Kimmel, J.; Jimenez, J.

    2008-12-01

    The emission of organic compounds in the troposphere is important factor in the formation of secondary organic aerosol (SOA). A very large proportion of organic material emitted globally is estimated to arise from biogenic sources, with almost half coming from tropical and sub-tropical forests. Preliminary analyses of leave cuvette emission studies suggest that oil palm (Elaeis guineensis) is a significantly larger source of isoprene than tropical forest. Much larger sources of isoprene over oil palm allied with a larger anthropogenic component of local emissions contrast greatly with the remote tropical forest environment and therefore the character of SOA formed may differ significantly. These issues, allied with the high price of palm oil on international markets leading to increased use of land for oil palm production, could give rise to rapidly changing chemical and aerosol regimes in the tropics. It is therefore important to understand the current emissions and composition of organic aerosol over all important land-uses in the tropical environment. This in turn will lead to a greater understanding of the present, and to an improvement in predictive capacity for the future system. To help address these issues, a high resolution time of flight aerosol mass spectrometer (HR-ToF-AMS) was deployed in the Sabahmas (PPB OIL) oil palm plantation near Lahad Datu, in Eastern Sabah, as part of the field component of the Aerosol Coupling in the Earth System (ACES) project, part of the UK NERC APPRAISE program. This project was allied closely with measurements made of similar chemical species and aerosol components at a forest site in the Danum Valley as part of the UK Oxidant and Particle Photochemical Processes above a Southeast Asian tropical rainforest (OP3) project. Measurements of submicron non- refractory aerosol composition are presented along with some preliminary analysis of chemically resolved aerosol fluxes made with a new eddy covariance system, based on the

  9. Knudsen effusion mass spectrometry. Chapter 20

    International Nuclear Information System (INIS)

    The Knudsen effusion mass spectrometric method for the determination of vapour pressures and thermodynamic properties is described. The aim of the article is to give a general introduction to the method rather than to give a critical review of the technique. The latest developments in this area of research are reviewed by the peers in the field during the triennial international mass spectrometric conferences. The Knudsen effusion mass spectrometric method is being applied for thermodynamic measurements. In recent times, laser vaporisation mass spectrometric methods have emerged as a source of determination of vapour pressures at very high temperatures and beyond the pressure regime far exceeding Knudsen effusion range

  10. Characterization of aerosol composition, concentrations, and sources at Baengnyeong Island, Korea using an aerosol mass spectrometer

    Science.gov (United States)

    Lee, Taehyoung; Choi, Jinsoo; Lee, Gangwoong; Ahn, Junyoung; Park, Jin Soo; Atwood, Samuel A.; Schurman, Misha; Choi, Yongjoo; Chung, Yoomi; Collett, Jeffrey L.

    2015-11-01

    To improve understanding of the sources and chemical properties of particulate pollutants on the western side of the Korean Peninsula, an Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) measured non-refractory fine (PM1) particles from May to November, 2011 at Baengnyeong Island, South Korea. Organic matter and sulfate were generally the most abundant species and exhibited maximum concentrations of 36 μg/m3 and 39 μg/m3, respectively. Nitrate concentrations peaked at 32 μg/m3 but were typically much lower than sulfate and organic matter concentrations. May, September, October, and November featured the highest monthly average concentrations, with lower concentrations typically observed from June through August. Potential source contribution function (PSCF) analysis and individual case studies revealed that transport from eastern China, an area with high SO2 emissions, was associated with high particulate sulfate concentrations at the measurement site. Observed sulfate aerosol sometimes was fully neutralized by ammonium but often was acidic; the average ammonium to sulfate molar ratio was 1.49. Measured species size distributions revealed a range of sulfate particle size distributions with modes between 100 and 600 nm. Organic aerosol source regions were widespread, including contributions from eastern China and South Korea. Positive matrix factorization (PMF) analysis indicated three "factors," or types of organic aerosol, comprising one primary, hydrocarbon-like organic aerosol (HOA) and two oxidized organic aerosol (OOA) components, including a more oxidized (MO-OOA) and a less oxidized (LO-OOA) oxidized organic aerosol. On average, HOA and OOA contributed 21% and 79% of the organic mass (OM), respectively, with the MO-OOA fraction nearly three times as abundant as the LO-OOA fraction. Biomass burning contributions to observed OM were low during the late spring/early summer agricultural burning season in eastern China, since

  11. Direct analysis of samples by mass spectrometry: From elements to bio-molecules using laser ablation inductively couple plasma mass spectrometry and laser desorption/ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Perdian, David C. [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Mass spectrometric methods that are able to analyze solid samples or biological materials with little or no sample preparation are invaluable to science as well as society. Fundamental research that has discovered experimental and instrumental parameters that inhibit fractionation effects that occur during the quantification of elemental species in solid samples by laser ablation inductively coupled plasma mass spectrometry is described. Research that determines the effectiveness of novel laser desorption/ionization mass spectrometric methods for the molecular analysis of biological tissues at atmospheric pressure and at high spatial resolution is also described. A spatial resolution is achieved that is able to analyze samples at the single cell level.

  12. Advanced Mass Calibration and Visualization for FT-ICR Mass Spectrometry Imaging

    CERN Document Server

    Smith, Donald F; Konijnenburg, Marco; Klinkert, Ivo; Pasa-Tolic, Ljiljana; Heeren, Ron M A

    2013-01-01

    Mass spectrometry imaging by Fourier transform ion cyclotron resonance yields hundreds of unique peaks, many of which cannot be resolved by lower performance mass spectrometers. The high mass accuracy and high mass resolving power allow confident identification of small molecules and lipids directly from biological tissue sections. Here, calibration strategies for Fourier transform ion cyclotron resonance mass spectrometry imaging were investigated. Sub parts-per-million mass accuracy is demonstrated over an entire tissue section. Ion abundance fluctuations are corrected for by addition of total and relative ion abundances for a root-mean-square error of 0.158 ppm on 16,764 peaks. A new approach for visualization of Fourier transform ion cyclotron resonance mass spectrometry imaging data at high resolution is presented. The Mosaic Data-cube provides a flexible means to visualize the entire mass range at a mass spectral bin width of 0.001 Dalton. The high resolution Mosaic Data-cube resolves spectral features ...

  13. Rare earth aerosol analysis by x-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    An analytical method for the determination of four lanthanides in air filter samples is described. The method involves simultaneous quantitative determinations of La, Ce, Pr, and Nd at the microgram level by x-ray fluorescence spectrometry without chemical separation of these rare earths and without serious interferences from the dust matrices on the filters. The method has been used successfully to analyze some air filter samples collected at a rare earth processing refinery in Illinois. A description of the development of the method is given as well as the results obtained by using this method on the air filter samples. The reproducibility of the results was generally +-5%

  14. Aerosol chemical elemental mass concentration at lower free troposphere

    Science.gov (United States)

    do Carmo Freitas, Maria; Dionísio, Isabel; Fialho, Paulo; Barata, Filipe

    2007-08-01

    This paper shows the use of Instrumental neutron activation analysis (INAA) technique to determine elemental masses collected by a seven-wavelength Aethalometer instrument at the summit of Pico mountain in the Azorean archipelago, situated in the Central North Atlantic Ocean. Each sample corresponds to air particulate matter measured continuously for periods of approximately 24 h taken from 14th July 2001 through 14th July 2002. The statistical analysis of the coefficients of correlation between all the elements identified, permitted to establish six groups that could potentially be associated with the type of source responsible for the aerosol sampled in the lower free troposphere at the Azorean archipelago. Calculation of the synoptic back trajectories helped to corroborate the use of the iron/cesium relation as a tracer for the Saharan dust aerosol. It was demonstrated that INAA constituted an important tool to identify these events.

  15. T cells recognizing a peptide contaminant undetectable by mass spectrometry

    DEFF Research Database (Denmark)

    Brezar, Vedran; Culina, Slobodan; Østerbye, Thomas;

    2011-01-01

    Synthetic peptides are widely used in immunological research as epitopes to stimulate their cognate T cells. These preparations are never completely pure, but trace contaminants are commonly revealed by mass spectrometry quality controls. In an effort to characterize novel major histocompatibility...... complex (MHC) Class I-restricted ß-cell epitopes in non-obese diabetic (NOD) mice, we identified islet-infiltrating CD8+ T cells recognizing a contaminating peptide. The amount of this contaminant was so small to be undetectable by direct mass spectrometry. Only after concentration by liquid...

  16. Radiogas chromatography mass spectrometry in the selected ion monitoring mode

    International Nuclear Information System (INIS)

    The value of selected ion monitoring in analyzing biological radio isotope incorporation experiments by radiogas chromatography mass spectrometry is illustrated with reference to the biosynthesis of the mycotoxin mycophenolic acid in Penicillium brevicompactum and the mode of action of the anticholesterolemic drug 20,25-diazacholesterol. Both examples used 1-[14C]acetate precursors. It is shown that the increased sensitivity and specificity of the selected ion monitoring mode detector permits straightforward detection and identification of the relatively small cellular pools associated with metabolic intermediates. The computer program RADSIM is described. Problems that still exist in using radiogas gas chromatography mass spectrometry technology to analyse isotope incorporation experiments are discussed. (author)

  17. Structure Determination of Natural Products by Mass Spectrometry

    Science.gov (United States)

    Biemann, Klaus

    2015-07-01

    I review laboratory research on the development of mass spectrometric methodology for the determination of the structure of natural products of biological and medical interest, which I conducted from 1958 to the end of the twentieth century. The methodology was developed by converting small peptides to their corresponding polyamino alcohols to make them amenable to mass spectrometry, thereby making it applicable to whole proteins. The structures of alkaloids were determined by analyzing the fragmentation of a known alkaloid and then using the results to deduce the structures of related compounds. Heparin-like structures were investigated by determining their molecular weights from the mass of protonated molecular ions of complexes with highly basic, synthetic peptides. Mass spectrometry was also employed in the analysis of lunar material returned by the Apollo missions. A miniaturized gas chromatograph mass spectrometer was sent to Mars on board of the two Viking 1976 spacecrafts.

  18. Development and characterization of a single particle laser ablation mass spectrometer (SPLAM for organic aerosol studies

    Directory of Open Access Journals (Sweden)

    F. Gaie-Levrel

    2011-07-01

    Full Text Available A single particle instrument has been developed for real-time analysis of organic aerosols. This instrument, named Single Particle Laser Ablation Mass Spectrometry (SPLAM, samples particles using an aerodynamic lens system for which the theoretical performances were calculated. At the outlet of this system, particle detection and sizing are realized using two continuous diode lasers operating at λ = 403 nm. Polystyrene Latex (PSL, sodium chloride (NaCl and dioctylphtalate (DOP particles were used to characterize and calibrate optical detection of SPLAM. The optical detection limit (DL and detection efficiency (DE were determined using size-selected DOP particles. The DE is ranging from 0.1 to 90 % for 100 and 350 nm DOP particles respectively and the SPLAM instrument is able to detect and size-resolve particles as small as 110–120 nm. Scattered light is detected by two photomultipliers and the detected signals are used to trigger a UV excimer laser (λ = 248 nm used for laser desorption ionization (LDI of individual aerosol particles. The formed ions are analyzed by a 1 m linear time-of-flight mass spectrometer in order to access to the chemical composition of individual particles. The TOF-MS detection limit for gaseous aromatic compounds was determined to be 0.85 attograms. DOP particles were also used to test the overall functioning of the instrument. The analysis of a secondary organic aerosol, formed in a smog chamber by the ozonolysis of indene, is presented as a first scientific application of the instrument. Single particle mass spectra are obtained with a global hit rate of 10 %. They are found to be very different from one particle to another, reflecting chemical differences of the analyzed particles, and most of the detected mass peaks are attributed to oxidized products of indene.

  19. Source apportionment of submicron organic aerosols at an urban site by linear unmixing of aerosol mass spectra

    Directory of Open Access Journals (Sweden)

    V. A. Lanz

    2006-11-01

    Full Text Available Submicron ambient aerosol was characterized in summer 2005 at an urban background site in Zurich, Switzerland, during a three-week measurement campaign. Highly time-resolved samples of non-refractory aerosol components were analyzed with an Aerodyne aerosol mass spectrometer (AMS. Positive matrix factorization (PMF was used for the first time for AMS data to identify the main components of the total organic aerosol and their sources. The PMF retrieved factors were compared to measured reference mass spectra and were correlated with tracer species of the aerosol and gas phase measurements from collocated instruments. Six factors were found to explain virtually all variance in the data and could be assigned either to sources or to aerosol components such as oxygenated organic aerosol (OOA. Our analysis suggests that at the measurement site only a small (<10% fraction of organic PM1 originates from freshly emitted fossil fuel combustion. Other primary sources identified to be of similar or even higher importance are charbroiling (10–15% and wood burning (~10%, along with a minor source interpreted to be influenced by food cooking (6%. The fraction of all identified primary sources is considered as primary organic aerosol (POA. This interpretation is supported by calculated ratios of the modelled POA and measured primary pollutants such as elemental carbon (EC, NOx, and CO, which are in good agreement to literature values. A high fraction (60–69% of the measured organic aerosol mass is OOA which is interpreted mostly as secondary organic aerosol (SOA. This oxygenated organic aerosol can be separated into a highly aged fraction, OOA I, (40–50% with low volatility and a mass spectrum similar to fulvic acid, and a more volatile and probably less processed fraction, OOA II (on average 20%. This is the first publication of a multiple component analysis technique to AMS organic spectral data and also the first report of the

  20. Hybrid ion mobility and mass spectrometry as a separation tool.

    Science.gov (United States)

    Ewing, Michael A; Glover, Matthew S; Clemmer, David E

    2016-03-25

    Ion mobility spectrometry (IMS) coupled to mass spectrometry (MS) has seen spectacular growth over the last two decades. Increasing IMS sensitivity and capacity with improvements in MS instrumentation have driven this growth. As a result, a diverse new set of techniques for separating ions by their mobility have arisen, each with characteristics that make them favorable for some experiments and some mass spectrometers. Ion mobility techniques can be broken down into dispersive and selective techniques based upon whether they pass through all mobilities for later analysis by mass spectrometry or select ions by mobility or a related characteristic. How ion mobility techniques fit within a more complicated separation including mass spectrometry and other techniques such as liquid chromatography is of fundamental interest to separations scientists. In this review we explore the multitude of ion mobility techniques hybridized to different mass spectrometers, detailing current challenges and opportunities for each ion mobility technique and for what experiments one technique might be chosen over another. The underlying principles of ion mobility separations, including: considerations regarding separation capabilities, ion transmission, signal intensity and sensitivity, and the impact that the separation has upon the ion structure (i.e., the possibility of configurational changes due to ion heating) are discussed.

  1. Analysis of proteins and proteomes by mass spectrometry.

    Science.gov (United States)

    Mann, M; Hendrickson, R C; Pandey, A

    2001-01-01

    A decade after the discovery of electrospray and matrix-assisted laser desorption ionization (MALDI), methods that finally allowed gentle ionization of large biomolecules, mass spectrometry has become a powerful tool in protein analysis and the key technology in the emerging field of proteomics. The success of mass spectrometry is driven both by innovative instrumentation designs, especially those operating on the time-of-flight or ion-trapping principles, and by large-scale biochemical strategies, which use mass spectrometry to detect the isolated proteins. Any human protein can now be identified directly from genome databases on the basis of minimal data derived by mass spectrometry. As has already happened in genomics, increased automation of sample handling, analysis, and the interpretation of results will generate an avalanche of qualitative and quantitative proteomic data. Protein-protein interactions can be analyzed directly by precipitation of a tagged bait followed by mass spectrometric identification of its binding partners. By these and similar strategies, entire protein complexes, signaling pathways, and whole organelles are being characterized. Posttranslational modifications remain difficult to analyze but are starting to yield to generic strategies.

  2. Principles of isotopic analysis by mass spectrometry

    International Nuclear Information System (INIS)

    The use of magnetic sector field mass spectrometers in isotopic analysis, especially for nitrogen gas, is outlined. Two measuring methods are pointed out: the scanning mode for significantly enriched samples and the double collector method for samples near the natural abundance of 15N. The calculation formulas are derived and advice is given for corrections. (author)

  3. Development and characterization of a single particle laser ablation mass spectrometer (SPLAM for organic aerosol studies

    Directory of Open Access Journals (Sweden)

    F. Gaie-Levrel

    2012-01-01

    Full Text Available A single particle instrument was developed for real-time analysis of organic aerosol. This instrument, named Single Particle Laser Ablation Mass Spectrometry (SPLAM, samples particles using an aerodynamic lens system for which the theoretical performances were calculated. At the outlet of this system, particle detection and sizing are realized by using two continuous diode lasers operating at λ = 403 nm. Polystyrene Latex (PSL, sodium chloride (NaCl and dioctylphtalate (DOP particles were used to characterize and calibrate optical detection of SPLAM. The optical detection limit (DL and detection efficiency (DE were determined using size-selected DOP particles. The DE ranges from 0.1 to 90% for 100 and 350 nm DOP particles respectively and the SPLAM instrument is able to detect and size-resolve particles as small as 110–120 nm. During optical detection, particle scattered light from the two diode lasers, is detected by two photomultipliers and the detected signals are used to trigger UV excimer laser (λ = 248 nm used for one-step laser desorption ionization (LDI of individual aerosol particles. The formed ions are analyzed by a 1 m linear time-of-flight mass spectrometer in order to access to the chemical composition of individual particles. The TOF-MS detection limit for gaseous aromatic compounds was determined to be 0.85 × 10−15 kg (∼4 × 103 molecules. DOP particles were also used to test the overall operation of the instrument. The analysis of a secondary organic aerosol, formed in a smog chamber by the ozonolysis of indene, is presented as a first application of the instrument. Single particle mass spectra were obtained with an effective hit rate of 8%. Some of these mass spectra were found to be very different from one particle to another possibly reflecting chemical differences within the investigated indene SOA particles. Our study shows that an exhaustive statistical analysis, over hundreds of particles

  4. High-accuracy mass spectrometry for fundamental studies.

    Science.gov (United States)

    Kluge, H-Jürgen

    2010-01-01

    Mass spectrometry for fundamental studies in metrology and atomic, nuclear and particle physics requires extreme sensitivity and efficiency as well as ultimate resolving power and accuracy. An overview will be given on the global status of high-accuracy mass spectrometry for fundamental physics and metrology. Three quite different examples of modern mass spectrometric experiments in physics are presented: (i) the retardation spectrometer KATRIN at the Forschungszentrum Karlsruhe, employing electrostatic filtering in combination with magnetic-adiabatic collimation-the biggest mass spectrometer for determining the smallest mass, i.e. the mass of the electron anti-neutrino, (ii) the Experimental Cooler-Storage Ring at GSI-a mass spectrometer of medium size, relative to other accelerators, for determining medium-heavy masses and (iii) the Penning trap facility, SHIPTRAP, at GSI-the smallest mass spectrometer for determining the heaviest masses, those of super-heavy elements. Finally, a short view into the future will address the GSI project HITRAP at GSI for fundamental studies with highly-charged ions.

  5. High-accuracy mass spectrometry for fundamental studies.

    Science.gov (United States)

    Kluge, H-Jürgen

    2010-01-01

    Mass spectrometry for fundamental studies in metrology and atomic, nuclear and particle physics requires extreme sensitivity and efficiency as well as ultimate resolving power and accuracy. An overview will be given on the global status of high-accuracy mass spectrometry for fundamental physics and metrology. Three quite different examples of modern mass spectrometric experiments in physics are presented: (i) the retardation spectrometer KATRIN at the Forschungszentrum Karlsruhe, employing electrostatic filtering in combination with magnetic-adiabatic collimation-the biggest mass spectrometer for determining the smallest mass, i.e. the mass of the electron anti-neutrino, (ii) the Experimental Cooler-Storage Ring at GSI-a mass spectrometer of medium size, relative to other accelerators, for determining medium-heavy masses and (iii) the Penning trap facility, SHIPTRAP, at GSI-the smallest mass spectrometer for determining the heaviest masses, those of super-heavy elements. Finally, a short view into the future will address the GSI project HITRAP at GSI for fundamental studies with highly-charged ions. PMID:20530821

  6. Mass spectrometry instrumentation in TN (Novillo Tokamak)

    International Nuclear Information System (INIS)

    The mass spectrophotometry in the residual gases analysis in high vacuum systems, in particular in the Novillo Tokamak (TN), where pressures are required to be of the order 10-7 Torr, is carried out through an instrumental support with infrastructure configured in parallel to the experimental planning in this device. In the Novillo as well as other Tokamaks, it is necessary to condition the vacuum chamber for improving the main discharge parameters. At the present time, in this Tokamak the conditioning quality is presented determined by means of a mass spectrophotometer. A general instrumental description is presented associated with the Novillo conditioning, as well as the spectras obtained before and after operation. (Author)

  7. Calcium isotope analysis by mass spectrometry.

    Science.gov (United States)

    Boulyga, Sergei F

    2010-01-01

    The variations in the isotopic composition of calcium caused by fractionation in heterogeneous systems and by nuclear reactions can provide insight into numerous biological, geological, and cosmic processes, and therefore isotopic analysis finds a wide spectrum of applications in cosmo- and geochemistry, paleoclimatic, nutritional, and biomedical studies. The measurement of calcium isotopic abundances in natural samples has challenged the analysts for more than three decades. Practically all Ca isotopes suffer from significant isobaric interferences, whereas low-abundant isotopes can be particularly affected by neighboring major isotopes. The extent of natural variations of stable isotopes appears to be relatively limited, and highly precise techniques are required to resolve isotopic effects. Isotope fractionation during sample preparation and measurements and instrumental mass bias can significantly exceed small isotope abundance variations in samples, which have to be investigated. Not surprisingly, a TIMS procedure developed by Russell et al. (Russell et al., 1978. Geochim Cosmochim Acta 42: 1075-1090) for Ca isotope measurements was considered as revolutionary for isotopic measurements in general, and that approach is used nowadays (with small modifications) for practically all isotopic systems and with different mass spectrometric techniques. Nevertheless, despite several decades of calcium research and corresponding development of mass spectrometers, the available precision and accuracy is still not always sufficient to achieve the challenging goals. The present article discusses figures of merits of presently used analytical methods and instrumentation, and attempts to critically assess their limitations. In Sections 2 and 3, mass spectrometric methods applied to precise stable isotope analysis and to the determination of (41)Ca are described. Section 4 contains a short summary of selected applications, and includes tracer experiments and the potential use

  8. On-Line Synthesis and Analysis by Mass Spectrometry

    Science.gov (United States)

    Bain, Ryan M.; Pulliam, Christopher J.; Raab, Shannon A.; Cooks, R. Graham

    2015-01-01

    In this laboratory experiment, students learn how to use ESI to accelerate chemical synthesis and to couple it with on-line mass spectrometry for structural analysis. The Hantzsch synthesis of symmetric 1,4-dihydropyridines is a classic example of a one-pot reaction in which multiple intermediates can serve to indicate the progress of the reaction…

  9. Gas chromatography mass spectrometry : key technology in metabolomics

    NARCIS (Netherlands)

    Koek, Maud Marijtje

    2009-01-01

    Metabolomics involves the unbiased quantitative and qualitative analysis of the complete set of metabolites present in cells, body fluids and tissues. Gas chromatography coupled to mass spectrometry (GC-MS) is very suitable for metabolomics analysis, as it combines high separation power with sensiti

  10. Characterisation of cholera toxin by liquid chromatography - Electrospray mass spectrometry

    NARCIS (Netherlands)

    Baar, B.L.M. van; Hulst, A.G.; Wils, E.R.J.

    1999-01-01

    Cholera toxin, one of the toxins that may be generated by various strains of the bacterium Vibrio cholerae, can be considered as a substance possibly used in biological warfare. The possibilities of characterising the toxin by liquid chromatography electrospray mass spectrometry (LC-ES-MS) were inve

  11. High-Performance Liquid Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Vestal, Marvin L.

    1984-01-01

    Reviews techniques for online coupling of high-performance liquid chromatography with mass spectrometry, emphasizing those suitable for application to nonvolatile samples. Also summarizes the present status, strengths, and weaknesses of various techniques and discusses potential applications of recently developed techniques for combined liquid…

  12. Traveling-wave ion mobility mass spectrometry of protein complexes

    DEFF Research Database (Denmark)

    Salbo, Rune; Bush, Matthew F; Naver, Helle;

    2012-01-01

    The collision cross-section (Ω) of a protein or protein complex ion can be measured using traveling-wave (T-wave) ion mobility (IM) mass spectrometry (MS) via calibration with compounds of known Ω. The T-wave Ω-values depend strongly on instrument parameters and calibrant selection. Optimization of...

  13. Multiple parallel mass spectrometry for lipid and vitamin D analysis

    Science.gov (United States)

    Liquid chromatography (LC) coupled to mass spectrometry (MS) has become the method of choice for analysis of complex lipid samples. Two types of ionization sources have emerged as the most commonly used to couple LC to MS: atmospheric pressure chemical ionization (APCI) and electrospray ionization ...

  14. Analysis of essential oils by gas chromatography and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Masada, Y.

    1976-01-01

    The book is in two parts: first part Essential Oil includes compositae; labiatae; verbenaceae; oleaceae; umbelliferae; myrtaceae; euphorbiaceae; rutaceae; geraniaceae; rosaceae; lauraceae; myristicaceae; anonaceae; santalaceae; moraceae; piperaceae; zingiberaceae; araceae; gramineae; and cupressaceae written in English and Japanese. Part two includes essential oil; gas chromatography, and mass spectrometry written in Japanese. (DP)

  15. Negative ion-atmospheric pressure photoionization-mass spectrometry

    NARCIS (Netherlands)

    Kauppila, T.J.; Kotiaho, T.; Kostiainen, R; Bruins, A.P.

    2004-01-01

    The ionization mechanism in the novel atmospheric pressure photoionization mass spectrometry (APPI-MS) in negative ion mode was studied thoroughly by the analysis of seven compounds in 17 solvent systems. The compounds possessed either gas-phase acidity or positive electron affinity, whereas the sol

  16. Specialized Gas Chromatography--Mass Spectrometry Systems for Clinical Chemistry.

    Science.gov (United States)

    Gochman, Nathan; And Others

    1979-01-01

    A discussion of the basic design and characteristics of gas chromatography-mass spectrometry systems used in clinical chemistry. A comparison of three specific systems: the Vitek Olfax IIA, Hewlett-Packard HP5992, and Du Pont DP-102 are included. (BB)

  17. May the Best Molecule Win: Competition ESI Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Sarah Laughlin

    2015-10-01

    Full Text Available Electrospray ionization mass spectrometry has become invaluable in the characterization of macromolecular biological systems such as nucleic acids and proteins. Recent advances in the field of mass spectrometry and the soft conditions characteristic of electrospray ionization allow for the investigation of non-covalent interactions among large biomolecules and ligands. Modulation of genetic processes through the use of small molecule inhibitors with the DNA minor groove is gaining attention as a potential therapeutic approach. In this review, we discuss the development of a competition method using electrospray ionization mass spectrometry to probe the interactions of multiple DNA sequences with libraries of minor groove binding molecules. Such an approach acts as a high-throughput screening method to determine important information including the stoichiometry, binding mode, cooperativity, and relative binding affinity. In addition to small molecule-DNA complexes, we highlight other applications in which competition mass spectrometry has been used. A competitive approach to simultaneously investigate complex interactions promises to be a powerful tool in the discovery of small molecule inhibitors with high specificity and for specific, important DNA sequences.

  18. Triple Bioaffinity Mass Spectrometry Concept for Thyroid Transporter Ligands

    NARCIS (Netherlands)

    Aqai, P.; Fryganas, C.; Mizuguchi, M.; Haasnoot, W.; Nielen, M.W.F.

    2012-01-01

    For the analysis of thyroid transporter ligands, a triple bioaffinity mass spectrometry (BioMS) concept was developed, with the aim at three different analytical objectives: rapid screening of any ligand, confirmation of known ligands in accordance with legislative requirements, and identification o

  19. Quantitative matrix-assisted laser desorption/ionization mass spectrometry

    OpenAIRE

    Duncan, Mark W.; Roder, Heinrich; Hunsucker, Stephen W.

    2008-01-01

    This review summarizes the essential characteristics of matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry (TOF MS), especially as they relate to its applications in quantitative analysis. Approaches to quantification by MALDI-TOF MS are presented and published applications are critically reviewed.

  20. Proteogenomic analysis of Candida glabrata using high resolution mass spectrometry.

    NARCIS (Netherlands)

    Prasad, T.S.; Harsha, H.C.; Keerthikumar, S.; Sekhar, N.R.; Selvan, L.D.N.; Kumar, P.; Pinto, S.M.; Muthusamy, B.; Subbannayya, Y.; Renuse, S.; Chaerkady, R.; Mathur, P.P.; Ravikumar, R.; Pandey, A.

    2012-01-01

    Candida glabrata is a common opportunistic human pathogen leading to significant mortality in immunosuppressed and immunodeficient individuals. We carried out proteomic analysis of C. glabrata using high resolution Fourier transform mass spectrometry with MS resolution of 60,000 and MS/MS resolution

  1. Fusion of mass spectrometry-based metabolomics data

    NARCIS (Netherlands)

    Smilde, A.K.; Werf, M.J. van der; Bijlsma, S.; Werff-van der Vat, B.J.C. van der; Jellema, R.H.

    2005-01-01

    A general method is presented for combining mass spectrometry-based metabolomics data. Such data are becoming more and more abundant, and proper tools for fusing these types of data sets are needed. Fusion of metabolomics data leads to a comprehensive view on the metabolome of an organism or biologi

  2. Mass Spectrometry Based Identifications of LMW Glutenin Subunits

    Science.gov (United States)

    Tandem mass spectrometry (MS/MS) is routinely used to identify wheat endosperm proteins. In this method, peptide fragmentation patterns generated by MS/MS are identified using a ‘search engine’ to compare the spectra to those generated in silico from protein sequence databases. Trypsin is a commonly...

  3. Exploring signal transduction networks using mass spectrometry-based proteomics

    NARCIS (Netherlands)

    Meijer, L.A.T.

    2012-01-01

    Mass spectrometry (MS)-based proteomics can be used to answer a diversity of biological questions. In this thesis, we describe the application of several MS-based proteomics approaches to get insight into several aspects of signal transduction. In Chapter 2, quantitative global phosphoproteomics are

  4. High Resolution Mass Spectrometry of Polyfluorinated Polyether-Based Formulation

    DEFF Research Database (Denmark)

    Dimzon, Ian Ken; Trier, Xenia; Frömel, Tobias;

    2016-01-01

    High resolution mass spectrometry (HRMS) was successfully applied to elucidate the structure of a polyfluorinated polyether (PFPE)-based formulation. The mass spectrum generated from direct injection into the MS was examined by identifying the different repeating units manually and with the aid o......-fluorinated polymers. The information from MS is essential in studying the physico-chemical properties of PFPEs and can help in assessing the risks they pose to the environment and to human health. Graphical Abstract ᅟ....

  5. Accelerator mass spectrometry as a bioanalytical tool for nutritional research

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, J.S.; Turteltaub, K.W.

    1997-09-01

    Accelerator Mass Spectrometry is a mass spectrometric method of detecting long-lived radioisotopes without regard to their decay products or half-life. The technique is normally applied to geochronology, but recently has been developed for bioanalytical tracing. AMS detects isotope concentrations to parts per quadrillion, quantifying labeled biochemicals to attomole levels in milligram- sized samples. Its advantages over non-isotopeic and stable isotope labeling methods are reviewed and examples of analytical integrity, sensitivity, specificity, and applicability are provided.

  6. Miniaturized analytical systems for mass spectrometry-based protein studies

    OpenAIRE

    Abonnenc, Mélanie

    2009-01-01

    Current proteomic strategies depend strongly on the development of analytical methodologies and instrumentation. In parallel to the development of mass spectrometry (MS) - based proteomic workflows, microfluidic devices emerged in this field as a flexible tool for rapid and sensitive protein studies. In this context, the present work focuses on the development of miniaturized analytical systems for protein studies, especially by electrospray ionization mass spectrometric detection. Several ap...

  7. Direct and Convenient Mass Spectrometry Sampling with Ambient Flame Ionization

    OpenAIRE

    Xiao-Pan Liu; Hao-Yang Wang; Jun-Ting Zhang; Meng-Xi Wu; Wan-Shu Qi; Hui Zhu; Yin-Long Guo

    2015-01-01

    Recent innovations in ambient ionization technology for the direct analysis of various samples in their native environment facilitate the development and applications of mass spectrometry in natural science. Presented here is a novel, convenient and flame-based ambient ionization method for mass spectrometric analysis of organic compounds, termed as the ambient flame ionization (AFI) ion source. The key features of AFI ion source were no requirement of (high) voltages, laser beams and spray g...

  8. Measurement of boron isotopes by negative thermal ionization mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The isobaric interference for boron isotopic measurement by negative thermal ionization mass spectrometry (NTIMS) has been studied. The result shows that the CNO- is not only from the organic material, but also from nitrate in loading reagent in NTIMS. Monitoring the mass 43 ion intensity and 43/42 ratio of blank are also necessary for the boron isotopic measurement by NTIMS, other than is only boron content.

  9. Structural Characterization of Carbohydrates by Fourier Transform Tandem Mass Spectrometry

    OpenAIRE

    Zhou, Wen; Håkansson, Kristina

    2011-01-01

    Fourier transform tandem mass spectrometry (MS/MS) provides high mass accuracy, high sensitivity, and analytical versatility and has therefore emerged as an indispensable tool for structural elucidation of biomolecules. Glycosylation is one of the most common posttranslational modifications, occurring in ~50% of proteins. However, due to the structural diversity of carbohydrates, arising from non-template driven biosynthesis, achievement of detailed structural insight is highly challenging. T...

  10. New high temperature plasmas and sample introduction systems for analytical atomic emission and mass spectrometry

    Science.gov (United States)

    Montaser, A.

    In this project, new high temperature plasmas and new sample introduction systems are developed for rapid elemental and isotopic analysis of gases, solutions, and solids using atomic emission spectrometry (AES) and mass spectrometry (MS). These devices offer promise of solving singularly difficult analytical problems that either exist now or are likely to arise in the future in the various fields of energy generation, environmental pollution, nutrition, and biomedicine. Emphasis is being placed on: (1) generation of annular, helium inductively coupled plasmas (He ICPs) that are suitable for atomization, excitation, and ionization of elements possessing high excitation and ionization energies, with the intent of enhancing the detecting powers of a number of elements; (2) computer modelings of ICP discharges to predict the behavior of new and existing plasmas; (3) diagnostic studies of high temperature plasmas and sample introduction systems to quantify their fundamental properties, with the ultimate aim to improve analytical performance of atomic spectrometry; (4) development and characterization of new, low cost sample introduction systems that consume microliter or microgram quantities of samples; and (5) investigation of new membrane separators for stripping solvent from sample aerosol to reduce various interferences and to enhance sensitivity and selectivity in plasma spectrometry.

  11. Detailed mass analysis of structural heterogeneity in monoclonal antibodies using native mass spectrometry

    NARCIS (Netherlands)

    Rosati, Sara; Yang, Yang; Barendregt, Arjan; Heck, Albert J R

    2014-01-01

    The molecular complexity of biopharmaceuticals puts severe demands on the bioanalytical techniques required for their comprehensive structural characterization. Mass spectrometry (MS) has gained importance in the analysis of biopharmaceuticals, taking different complementary approaches ranging from

  12. Critical comparison of mass analyzers for forensic hair analysis by ambient ionizations mass spectrometry

    NARCIS (Netherlands)

    Duvivier, W.F.; Beek, van T.A.; Nielen, M.W.F.

    2016-01-01

    Rationale
    Recently, several direct and/or ambient mass spectrometry (MS) approaches have been suggested for drugs of abuse imaging in hair. The use of mass spectrometers with insufficient selectivity could result in false-positive measurements due to isobaric interferences. Different mass analyz

  13. Application of Laser Mass Spectrometry to Art and Archaeology

    Science.gov (United States)

    Gulian, Lase Lisa E.; Callahan, Michael P.; Muliadi, Sarah; Owens, Shawn; McGovern, Patrick E.; Schmidt, Catherine M.; Trentelman, Karen A.; deVries, Mattanjah S.

    2011-01-01

    REMPI laser mass spectrometry is a combination of resonance enhanced multiphoton ionization spectroscopy and time of flight mass spectrometry, This technique enables the collection of mass specific optical spectra as well as of optically selected mass spectra. Analytes are jet-cooled by entrainment in a molecular beam, and this low temperature gas phase analysis has the benefit of excellent vibronic resolution. Utilizing this method, mass spectrometric analysis of historically relevant samples can be simplified and improved; Optical selection of targets eliminates the need for chromatography while knowledge of a target's gas phase spectroscopy allows for facile differentiation of molecules that are in the aqueous phase considered spectroscopically indistinguishable. These two factors allow smaller sample sizes than commercial MS instruments, which in turn will require less damage to objects of antiquity. We have explored methods to optimize REMPI laser mass spectrometry as an analytical tool to archaeology using theobromine and caffeine as molecular markers in Mesoamerican pottery, and are expanding this approach to the field of art to examine laccaic acid in shellacs.

  14. Mass spectrometry and mass spectrography with spark source

    International Nuclear Information System (INIS)

    The analysis of geological materials for traces of elements can be performed using mass-spectrometric isotopic dilution, as well as mass-spectrography with a spark source. The review contains the data on the application of above analyses in geochemical analysis

  15. Hands-on Electrospray Ionization-Mass Spectrometry for Upper-Level Undergraduate and Graduate Students

    Science.gov (United States)

    Stock, Naomi L.; March, Raymond E.

    2014-01-01

    Electrospray ionization-mass spectrometry (ESI-MS) is a powerful technique for the detection, identification, and quantification of organic compounds. As mass spectrometers have become more user-friendly and affordable, many students--often with little experience in mass spectrometry--find themselves needing to incorporate mass spectrometry into…

  16. Photoionization mass spectrometry of UF6

    International Nuclear Information System (INIS)

    The photoionization mass spectrum of 238UF6 was obtained. At 600 A = 20.66 eV, the relative ionic abundances were as follows: UF6+, 1.4; UF5+, 100; UF+, 17; UF3+, approx. 0.7; UF2+, very weak; UF+, very weak; U+, essentially zero. The adiabatic ionization potential for UF6 was 13.897 +- 0.005 eV. The production of UF5+ begins at approx. 887 A = 13.98 eV, at which energy the UF6+ partial cross section abruptly declines and then levels off. This behavior suggests the vague possibility of an isotope effect. The UF4+ signal begins at approx. 725 A = 17.10 eV, at which energy the UF5+ signal reaches a plateau value. The UF5+ photoionization yield curve displays some autoionization structure from its threshold to approx. 750 A

  17. Principle and analytical applications of resonance ionization mass spectrometry

    International Nuclear Information System (INIS)

    Resonance ionization mass spectrometry (RIMS) is a very sensitive analytical technique for the detection of trace elements. This method is based on the excitation and ionization of atoms with resonant laser light followed by mass analysis. It allows element and, in some cases, isotope selective ionization and is applicable to most of the elements of the periodic table. A high selectivity can be achieved by applying three step photoionization of the elements under investigation and an additional mass separation for an unambiguous isotope assignment. An effective facility for resonance ionization mass spectrometry consists of three dye lasers which are pumped by two copper vapor lasers and of a linear time-of-flight spectrometer with a resolution better than 2500. Each copper vapor laser has a pulse repetition rate of 6,5 kHz and an average output power of 30 W. With such an apparatus measurements with lanthanide-, actinide-, and technetium-samples have been performed. By saturating the excitation steps and by using autoionizing states for ionization step a detection efficiency of 4 x 10-6 and 2,5 x 10-6 has been reached for plutonium and technetium, respectively, leading to a detection limit of less than 107 atoms in the sample. Measurements of isotope ratios of plutonium samples were in good agreement with mass-spectrometric data. The high elemental selectivity of the resonance ionization spectrometry could be demonstrated. (Authors)

  18. Recent developments in Penning-trap mass spectrometry

    Science.gov (United States)

    Block, M.

    2016-06-01

    Penning-trap mass spectrometry provides atomic masses with the highest precision. At accelerator-based on-line facilities it is applied to investigate exotic radionuclides in the context of tests of fundamental symmetries, nuclear structure studies, and nuclear astrophysics research. Recent progress in slowing down radioactive ion-beams in buffer-gas cells in combination with advanced ion-manipulation techniques has paved the way to reach nuclides ever-more far from stability. In this endeavor many efforts are underway to increase the sensitivity, the efficiency, and the precision of Penning-trap mass spectrometry. In this article some recent experimental developments are addressed with the focus on the phase-imaging ion-cyclotron-resonance technique and the Fourier transform ion-cyclotron-resonance technique.

  19. Data Processing for 3D Mass Spectrometry Imaging

    Science.gov (United States)

    Xiong, Xingchuang; Xu, Wei; Eberlin, Livia S.; Wiseman, Justin M.; Fang, Xiang; Jiang, You; Huang, Zejian; Zhang, Yukui; Cooks, R. Graham; Ouyang, Zheng

    2012-06-01

    Data processing for three dimensional mass spectrometry (3D-MS) imaging was investigated, starting with a consideration of the challenges in its practical implementation using a series of sections of a tissue volume. The technical issues related to data reduction, 2D imaging data alignment, 3D visualization, and statistical data analysis were identified. Software solutions for these tasks were developed using functions in MATLAB. Peak detection and peak alignment were applied to reduce the data size, while retaining the mass accuracy. The main morphologic features of tissue sections were extracted using a classification method for data alignment. Data insertion was performed to construct a 3D data set with spectral information that can be used for generating 3D views and for data analysis. The imaging data previously obtained for a mouse brain using desorption electrospray ionization mass spectrometry (DESI-MS) imaging have been used to test and demonstrate the new methodology.

  20. POTAMOS mass spectrometry calculator: computer aided mass spectrometry to the post-translational modifications of proteins. A focus on histones.

    Science.gov (United States)

    Vlachopanos, A; Soupsana, E; Politou, A S; Papamokos, G V

    2014-12-01

    Mass spectrometry is a widely used technique for protein identification and it has also become the method of choice in order to detect and characterize the post-translational modifications (PTMs) of proteins. Many software tools have been developed to deal with this complication. In this paper we introduce a new, free and user friendly online software tool, named POTAMOS Mass Spectrometry Calculator, which was developed in the open source application framework Ruby on Rails. It can provide calculated mass spectrometry data in a time saving manner, independently of instrumentation. In this web application we have focused on a well known protein family of histones whose PTMs are believed to play a crucial role in gene regulation, as suggested by the so called "histone code" hypothesis. The PTMs implemented in this software are: methylations of arginines and lysines, acetylations of lysines and phosphorylations of serines and threonines. The application is able to calculate the kind, the number and the combinations of the possible PTMs corresponding to a given peptide sequence and a given mass along with the full set of the unique primary structures produced by the possible distributions along the amino acid sequence. It can also calculate the masses and charges of a fragmented histone variant, which carries predefined modifications already implemented. Additional functionality is provided by the calculation of the masses of fragments produced upon protein cleavage by the proteolytic enzymes that are most widely used in proteomics studies. PMID:25450216

  1. Trends in biochemical and biomedical applications of mass spectrometry

    Science.gov (United States)

    Gelpi, Emilio

    1992-09-01

    This review attempts an in-depth evaluation of progress and achievements made since the last 11th International Mass Spectrometry Conference in the application of mass spectrometric techniques to biochemistry and biomedicine. For this purpose, scientific contributions in this field at major international meetings have been monitored, together with an extensive appraisal of literature data covering the period from 1988 to 1991. A bibliometric evaluation of the MEDLINE database for this period provides a total of almost 4000 entries for mass spectrometry. This allows a detailed study of literature and geographical sources of the most frequent applications, of disciplines where mass spectrometry is most active and of types of sample and instrumentation most commonly used. In this regard major efforts according to number of publications (over 100 literature reports) are concentrated in countries like Canada, France, Germany, Italy, Japan, Sweden, UK and the USA. Also, most of the work using mass spectrometry in biochemistry and biomedicine is centred on studies on biotransformation, metabolism, pharmacology, pharmacokinetics and toxicology, which have been carried out on samples of blood, urine, plasma and tissue, by order of frequency of use. Human and animal studies appear to be evenly distributed in terms of the number of reports published in the literature in which the authors make use of experimental animals or describe work on human samples. Along these lines, special attention is given to the real usefulness of mass spectrometry (MS) technology in routine medical practice. Thus the review concentrates on evaluating the progress made in disease diagnosis and overall patient care. As regards prevailing techniques, GCMS continues to be the mainstay of the state of the art methods for multicomponent analysis, stable isotope tracer studies and metabolic profiling, while HPLC--MS and tandem MS are becoming increasingly important in biomedical research. However

  2. Small system for tritium accelerator mass spectrometry

    Science.gov (United States)

    Roberts, Mark L.; Davis, Jay C.

    1993-01-01

    Apparatus for ionizing and accelerating a sample containing isotopes of hydrogen and detecting the ratios of hydrogen isotopes contained in the sample is disclosed. An ion source generates a substantially linear ion beam including ions of tritium from the sample. A radio-frequency quadrupole accelerator is directly coupled to and axially aligned with the source at an angle of substantially zero degrees. The accelerator accelerates species of the sample having different mass to different energy levels along the same axis as the ion beam. A spectrometer is used to detect the concentration of tritium ions in the sample. In one form of the invention, an energy loss spectrometer is used which includes a foil to block the passage of hydrogen, deuterium and .sup.3 He ions, and a surface barrier or scintillation detector to detect the concentration of tritium ions. In another form of the invention, a combined momentum/energy loss spectrometer is used which includes a magnet to separate the ion beams, with Faraday cups to measure the hydrogen and deuterium and a surface barrier or scintillation detector for the tritium ions.

  3. Microscale mass spectrometry systems, devices and related methods

    Science.gov (United States)

    Ramsey, John Michael

    2016-06-21

    Mass spectrometry systems or assemblies therefore include an ionizer that includes at least one planar conductor, a mass analyzer with a planar electrode assembly, and a detector comprising at least one planar conductor. The ionizer, the mass analyzer and the detector are attached together in a compact stack assembly. The stack assembly has a perimeter that bounds an area that is between about 0.01 mm.sup.2 to about 25 cm.sup.2 and the stack assembly has a thickness that is between about 0.1 mm to about 25 mm.

  4. High Mass Accuracy and High Mass Resolving Power FT-ICR Secondary Ion Mass Spectrometry for Biological Tissue Imaging

    CERN Document Server

    Smith, Donald F; Leach, Franklin E; Robinson, Errol W; Paša-Tolić, Ljiljana; Heeren, Ron M A

    2013-01-01

    Biological tissue imaging by secondary ion mass spectrometry has seen rapid development with the commercial availability of polyatomic primary ion sources. Endogenous lipids and other small bio-molecules can now be routinely mapped on the sub-micrometer scale. Such experiments are typically performed on time-of-flight mass spectrometers for high sensitivity and high repetition rate imaging. However, such mass analyzers lack the mass resolving power to ensure separation of isobaric ions and the mass accuracy for elemental formula assignment based on exact mass measurement. We have recently reported a secondary ion mass spectrometer with the combination of a C60 primary ion gun with a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) for high mass resolving power, high mass measurement accuracy and tandem mass spectrometry capabilities. In this work, high specificity and high sensitivity secondary ion FT-ICR MS was applied to chemical imaging of biological tissue. An entire rat brain tissu...

  5. Electrospray Ionization Mass Spectrometry of hexanitrohexaazaisowurtzitane (CL-20)

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, James A.; Szecsody, Jim E.; Devary, Brooks J.; Valenzuela, Blandina R.

    2007-09-03

    Hexanitrohexaazaisowurtzitane, (C6H6N12O12, MW 438) {CL-20}, is a high-energy propellent that has been recently developed and successfully tested (Nielsen et al. 1998). CL-20 releases more energy on ignition and is more stable to accidental detonation than currently used energetic materials. It is expected to replace many of the energetic materials currently being used by the Department of Defense (DoD). The EPA method 8330 (EPA 1997) for the analysis of explosives and metabolites in soils calls for the use of UV/Vis detection. High performance liquid chromatography has been used to quantify CL-20 and precursor concentration (Bazaki et al. 1998`) at relatively high concentrations. Fourier transform infrared (FTIR) spectroscopy has been used to identify different crystal forms of CL-20 (4 isomers; Kim et al. 1998). Campbell et al. (1997) utilized particle beam mass spectrometry for the analysis of enzymatic degradation of explosives. Introduction and recent improvements of ionization techniques such as electrospray (ES) have allowed the mass spectrometer to become more widely used in liquid chromatography. Schilling(1996) also examined explosive components and metabolites using electrospray (ES) and atmospheric pressure chemical ionization (APCI) liquid chromatography/mass spectrometry (LC/MS). Schilling’s results showed that compared to thermospray LC/MS, APCI and ES were more sensitive than thermospray by at least an order of magnitude. 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), 10 nitroso-RDX metabolites, and other munitions in ground water have been analyzed using solid phase extraction and isotope dilution liquid chromatography-APCI mass spectrometry (Cassada et al. 1999). The method detection limits indicate that nitramine and nitroaromatic compounds can be routinely determined in ground water samples using electrospray LC/MS with concentration techniques utilizing solid-phase extraction. Miller et al. (1996) studied nitrated explosives with mobile phase

  6. Metabolism of halogenated compounds in the white rot fungus Bjerkandera adusta studied by membrane inlet mass spectrometry and tandem mass spectrometry

    DEFF Research Database (Denmark)

    Beck, Hans Christian; Lauritsen, F.R.; Patrick, J.S.;

    1996-01-01

    Membrane inlet mass spectrometry has been used for the characterization of halogenated organic compounds produced by the fungus Bjerkandera adusta. Using this technique, electron impact-, chemical ionization-, electron capture negative chemical ionization-mass spectra and tandem mass spectra were...

  7. Advances in 193 nm excimer lasers for mass spectrometry applications

    Science.gov (United States)

    Delmdahl, Ralph; Esser, Hans-Gerd; Bonati, Guido

    2016-03-01

    Ongoing progress in mass analysis applications such as laser ablation inductively coupled mass spectrometry of solid samples and ultraviolet photoionization mediated sequencing of peptides and proteins is to a large extent driven by ultrashort wavelength excimer lasers at 193 nm. This paper will introduce the latest improvements achieved in the development of compact high repetition rate excimer lasers and elaborate on the impact on mass spectrometry instrumentation. Various performance and lifetime measurements obtained in a long-term endurance test over the course of 18 months will be shown and discussed in view of the laser source requirements of different mass spectrometry tasks. These sampling type applications are served by excimer lasers delivering pulsed 193 nm output of several mJ as well as fast repetition rates which are already approaching one Kilohertz. In order to open up the pathway from the laboratory to broader market industrial use, sufficient component lifetimes and long-term stable performance behavior have to be ensured. The obtained long-term results which will be presented are based on diverse 193 nm excimer laser tube improvements aiming at e.g. optimizing the gas flow dynamics and have extended the operational life the laser tube for the first time over several billion pulses even under high duty-cycle conditions.

  8. New Types of Ionization Sources for Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    None

    2008-12-01

    The purpose of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle (Contractor) and MDS Sciex (Participant) and ESA, Inc. (Participant) is to research, develop and apply new types of ionization sources and sampling/inlet systems for analytical mass spectrometry making use of the Participants state-of-the-art atmospheric sampling mass spectrometry electrochemical cell technology instrumentation and ancillary equipment. The two overriding goals of this research project are: to understand the relationship among the various instrumental components and operational parameters of the various ion sources and inlet systems under study, the chemical nature of the gases, solvents, and analytes in use, and the nature and abundances of the ions ultimately observed in the mass spectrometer; and to develop new and better analytical and fundamental applications of these ion sources and inlet systems or alternative sources and inlets coupled with mass spectrometry on the basis of the fundamental understanding obtained in Goal 1. The end results of this work are expected to be: (1) an expanded utility for the ion sources and inlet systems under study (such as the analysis of new types of analytes) and the control or alteration of the ionic species observed in the gas-phase; (2) enhanced instrument performance as judged by operational figures-of-merit such as dynamic range, detection limits, susceptibility to matrix signal suppression and sensitivity; and (3) novel applications (such as surface sampling with electrospray) in both applied and fundamental studies. The research projects outlined herein build upon work initiated under the previous CRADA between the Contractor and MDS Sciex on ion sources and inlet systems for mass spectrometry. Specific ion source and inlet systems for exploration of the fundamental properties and practical implementation of these principles are given.

  9. Evolving mass spectra of the oxidized component of organic aerosol: results from aerosol mass spectrometer analyses of aged diesel emissions

    Directory of Open Access Journals (Sweden)

    A. M. Sage

    2007-07-01

    Full Text Available The species and chemistry responsible for secondary organic aerosol (SOA formation remain highly uncertain. Laboratory studies of the oxidation of individual, high-flux SOA precursors do not lead to particles with mass spectra (MS matching those of ambient aged organic material. And, the complexity of real organic particles challenges efforts to identify their chemical origins. We have previously hypothesized that SOA can form from the atmospheric oxidation of a large suite of precursors with varying vapor pressures. Here, we support this hypothesis by using an aerosol mass spectrometer to track the chemical evolution of diesel exhaust as it is photochemically oxidized in an environmental chamber. With explicit knowledge of the condensed-phase MS of the primary emissions from our engine, we are able to decompose each recorded MS into contributing primary and secondary spectra throughout the experiment. We find that the SOA MS becomes increasingly oxidized as a function of time, eventually reaching a final MS that closely resembles that of ambient aged organic particulate matter. This observation is consistent with the idea that lower vapor pressure, semi-volatile organic emissions can form condensable products with fewer generations of oxidation, and therefore, they form relatively less oxidized SOA very quickly.

  10. Analysis of atmospheric aerosols by atomic emission spectrometry with electrical discharge sampling

    International Nuclear Information System (INIS)

    A procedure is developed for the determination of the concentration of heavy metals (Pb, Mn, Cu, Ni, Zn, and Cd) in atmospheric air by atomic emission spectrometry with gas-discharge sampling onto the end of a standard carbon electrode. A design of a two-section sampler is proposed; the sampler provides the rapid determination of deposition factors for the deposition of heavy metals contained in aerosol particles onto the end of a carbon electrode. Examples of determining metal concentrations in a model sample of air and in atmospheric air and determination limits of metals deposited onto the end of a carbon electrode are given

  11. Application of Mass Spectrometry in the Synthesis and Characterization of Metal Nanoclusters.

    Science.gov (United States)

    Lu, Yizhong; Chen, Wei

    2015-11-01

    In recent years, mass spectrometry has been widely used in the characterization of metal nanoclusters. In this Feature, we first give an introductory tutorial on mass spectrometry and then highlight the versatile applications of mass spectrometry in accurately analyzing core size, atom-level composition, charge states, etc. of metal nanoclusters and size evolution during synthesis. Finally, some perspectives on the future applications of mass spectrometry in nanocluster research are given. PMID:26086315

  12. The Use of Gas Chromatography and Mass Spectrometry to Introduce General Chemistry Students to Percent Mass and Atomic Mass Calculations

    Science.gov (United States)

    Pfennig, Brian W.; Schaefer, Amy K.

    2011-01-01

    A general chemistry laboratory experiment is described that introduces students to instrumental analysis using gas chromatography-mass spectrometry (GC-MS), while simultaneously reinforcing the concepts of mass percent and the calculation of atomic mass. Working in small groups, students use the GC to separate and quantify the percent composition…

  13. ModelE2-TOMAS development and evaluation using aerosol optical depths, mass and number concentrations

    Directory of Open Access Journals (Sweden)

    Y. H. Lee

    2014-09-01

    Full Text Available The TwO-Moment Aerosol Sectional microphysics model (TOMAS has been integrated into the state-of-the-art general circulation model, GISS ModelE2. TOMAS has the flexibility to select a size resolution as well as the lower size cutoff. A computationally efficient version of TOMAS is used here, which has 15 size bins covering 3 nm to 10 μm aerosol dry diameter. For each bin, it simulates the total aerosol number concentration and mass concentrations of sulphate, pure elementary carbon (hydrophobic, mixed elemental carbon (hydrophilic, hydrophobic organic matter, hydrophilic organic matter, sea salt, mineral dust, ammonium, and aerosol-associated water. This paper provides a detailed description of the ModelE2-TOMAS model and evaluates the model against various observations including aerosol precursor gas concentrations, aerosol mass and number concentrations, and aerosol optical depths. Additionally, global budgets in ModelE2-TOMAS are compared with those of other global aerosol models, and the TOMAS model is compared to the default aerosol model in ModelE2, which is a bulk aerosol model. Overall, the ModelE2-TOMAS predictions are within the range of other global aerosol model predictions, and the model has a reasonable agreement with observations of sulphur species and other aerosol components as well as aerosol optical depth. However, ModelE2-TOMAS (as well as the bulk aerosol model cannot capture the observed vertical distribution of sulphur dioxide over the Pacific Ocean possibly due to overly strong convective transport. The TOMAS model successfully captures observed aerosol number concentrations and cloud condensation nuclei concentrations. Anthropogenic aerosol burdens in the bulk aerosol model running in the same host model as TOMAS (ModelE2 differ by a few percent to a factor of 2 regionally, mainly due to differences in aerosol processes including deposition, cloud processing, and emission parameterizations. Larger differences are found

  14. A nested mixture model for protein identification using mass spectrometry

    CERN Document Server

    Li, Qunhua; Stephens, Matthew; 10.1214/09-AOAS316

    2010-01-01

    Mass spectrometry provides a high-throughput way to identify proteins in biological samples. In a typical experiment, proteins in a sample are first broken into their constituent peptides. The resulting mixture of peptides is then subjected to mass spectrometry, which generates thousands of spectra, each characteristic of its generating peptide. Here we consider the problem of inferring, from these spectra, which proteins and peptides are present in the sample. We develop a statistical approach to the problem, based on a nested mixture model. In contrast to commonly used two-stage approaches, this model provides a one-stage solution that simultaneously identifies which proteins are present, and which peptides are correctly identified. In this way our model incorporates the evidence feedback between proteins and their constituent peptides. Using simulated data and a yeast data set, we compare and contrast our method with existing widely used approaches (PeptideProphet/ProteinProphet) and with a recently publis...

  15. Desorption and ionization processes in laser mass spectrometry

    International Nuclear Information System (INIS)

    In this thesis results are reported from a study on the desorption- and ionization process initiated by infra-red laser irradiation (LDMS) or ion bombardment (SIMS) of thin organic sample layers. The study is especially focused on the formation of quasimolecular ions under these conditions. Results of these investigations can be used for a better optimization of the LDMS and SIMS techniques in organic mass spectrometry. First, an overview is given of laser desorption mass spectrometry. Next, the coupling of the laser energy into the organic sample layer is investigated. It is concluded that the laser energy is primarily absorbed by the substrate material and not by the organic overlayer. The formation of quasi-molecular ions, either in the gas phase or in the substrate surface is investigated. The final section reports kinetic energy distributions for ions sputtered from organic solids and liquids. (Auth.)

  16. Quantitative aspects of inductively coupled plasma mass spectrometry

    Science.gov (United States)

    Bulska, Ewa; Wagner, Barbara

    2016-10-01

    Accurate determination of elements in various kinds of samples is essential for many areas, including environmental science, medicine, as well as industry. Inductively coupled plasma mass spectrometry (ICP-MS) is a powerful tool enabling multi-elemental analysis of numerous matrices with high sensitivity and good precision. Various calibration approaches can be used to perform accurate quantitative measurements by ICP-MS. They include the use of pure standards, matrix-matched standards, or relevant certified reference materials, assuring traceability of the reported results. This review critically evaluates the advantages and limitations of different calibration approaches, which are used in quantitative analyses by ICP-MS. Examples of such analyses are provided. This article is part of the themed issue 'Quantitative mass spectrometry'.

  17. Analysis of tear glucose concentration with electrospray ionization mass spectrometry.

    Science.gov (United States)

    Taormina, Christopher R; Baca, Justin T; Asher, Sanford A; Grabowski, Joseph J; Finegold, David N

    2007-02-01

    We have developed a mass spectrometry-based method that allows one to accurately determine the glucose concentration of tear fluid. We used a 1 microL micro-capillary to collect tear fluid from the tear meniscus with minimal irritation of the eye. We analyzed the 1 muL volume of collected tear fluid with liquid-chromatography electrospray ionization mass spectrometry with the use of D-glucose-6,6-d2 as an internal standard. Repeated measurements and a recovery experiment on pooled, onion-induced tears showed that the analysis of the glucose in tears was precise (4% relative standard deviation) and provided 100% recovery. We found the tear glucose concentration of one fasting nondiabetic subject to be 13 to 51 microM while the onion-induced tear glucose concentration of a different nondiabetic subject to be 211 to 256 microM. PMID:17084090

  18. Mass spectrometry as a quantitative tool in plant metabolomics.

    Science.gov (United States)

    Jorge, Tiago F; Mata, Ana T; António, Carla

    2016-10-28

    Metabolomics is a research field used to acquire comprehensive information on the composition of a metabolite pool to provide a functional screen of the cellular state. Studies of the plant metabolome include the analysis of a wide range of chemical species with very diverse physico-chemical properties, and therefore powerful analytical tools are required for the separation, characterization and quantification of this vast compound diversity present in plant matrices. In this review, challenges in the use of mass spectrometry (MS) as a quantitative tool in plant metabolomics experiments are discussed, and important criteria for the development and validation of MS-based analytical methods provided.This article is part of the themed issue 'Quantitative mass spectrometry'. PMID:27644967

  19. Decoding signalling networks by mass spectrometry-based proteomics

    DEFF Research Database (Denmark)

    Choudhary, Chuna Ram; Mann, Matthias

    2010-01-01

    Signalling networks regulate essentially all of the biology of cells and organisms in normal and disease states. Signalling is often studied using antibody-based techniques such as western blots. Large-scale 'precision proteomics' based on mass spectrometry now enables the system-wide characteriz......Signalling networks regulate essentially all of the biology of cells and organisms in normal and disease states. Signalling is often studied using antibody-based techniques such as western blots. Large-scale 'precision proteomics' based on mass spectrometry now enables the system...... perturbation. Current studies focus on phosphorylation, but acetylation, methylation, glycosylation and ubiquitylation are also becoming amenable to investigation. Large-scale proteomics-based signalling research will fundamentally change our understanding of signalling networks....

  20. Practical aspects of trapped ion mass spectrometry, 5 applications of ion trapping devices

    CERN Document Server

    March, Raymond E

    2009-01-01

    Examines ion/neutral and ion/ion reactions, ion spectroscopy, and the structural characterization of proteins and peptides using quadropole ion trap mass spectrometry, Fourier transform - ion cyclotron resonance (FT-ICR) mass spectrometry, and traveling wave ion mobility mass spectrometry.

  1. Determining the topology of virus assembly intermediates using ion mobility spectrometry-mass spectrometry.

    Science.gov (United States)

    Knapman, Tom W; Morton, Victoria L; Stonehouse, Nicola J; Stockley, Peter G; Ashcroft, Alison E

    2010-10-30

    We have combined ion mobility spectrometry-mass spectrometry with tandem mass spectrometry to characterise large, non-covalently bound macromolecular complexes in terms of mass, shape (cross-sectional area) and stability (dissociation) in a single experiment. The results indicate that the quaternary architecture of a complex influences its residual shape following removal of a single subunit by collision-induced dissociation tandem mass spectrometry. Complexes whose subunits are bound to several neighbouring subunits to create a ring-like three-dimensional (3D) architecture undergo significant collapse upon dissociation. In contrast, subunits which have only a single neighbouring subunit within a complex retain much of their original shape upon complex dissociation. Specifically, we have determined the architecture of two transient, on-pathway intermediates observed during in vitro viral capsid assembly. Knowledge of the mass, stoichiometry and cross-sectional area of each viral assembly intermediate allowed us to model a range of potential structures based on the known X-ray structure of the coat protein building blocks. Comparing the cross-sectional areas of these potential architectures before and after dissociation provided tangible evidence for the assignment of the topologies of the complexes, which have been found to encompass both the 3-fold and the 5-fold symmetry axes of the final icosahedral viral shell. Such insights provide unique information about virus assembly pathways that could allow the design of anti-viral therapeutics directed at the assembly step. This methodology can be readily applied to the structural characterisation of many other non-covalently bound macromolecular complexes and their assembly pathways.

  2. Standards for uranium hexafluoride (UF6) mass spectrometry

    OpenAIRE

    Richter, Stephan; Kühn, H.; TRUYENS Jan; MIALLE SÉBASTIEN; Aregbe, Yetunde

    2013-01-01

    For UF6 mass spectrometry two types of "standards" are equally important: firstly "documentary standards" which describe specific measurement techniques and associated calculations, and secondly "material standards" which are preferentially SItraceable certified isotopic reference materials, as e.g. provided by the European Commission's Institute for Reference Materials and Measurements (IRMM). Recently the IRMM has upgraded its facilities for uranium isotopic measurements using uranium he...

  3. Quantitative Proteomics Using Ultralow Flow Capillary Electrophoresis–Mass Spectrometry

    OpenAIRE

    Faserl, Klaus; Kremser, Leopold; Müller, Martin; Teis, David; Lindner, Herbert H.

    2015-01-01

    In this work, we evaluate the incorporation of an ultralow flow interface for coupling capillary electrophoresis (CE) and mass spectrometry (MS), in combination with reversed-phase high-pressure liquid chromatography (HPLC) fractionation as an alternate workflow for quantitative proteomics. Proteins, extracted from a SILAC (stable isotope labeling by amino acids in cell culture) labeled and an unlabeled yeast strain were mixed and digested enzymatically in solution. The resulting peptides wer...

  4. Proteomics and Mass Spectrometry Applications in Biomedical Research

    OpenAIRE

    Chow, M; Zheng, R; Silva-Sanchez, C.; Koh, J; Chen, S.; Diaz, C.

    2011-01-01

    Proteomics and mass spectrometry have provided unprecedented tools for fast, accurate, high throughput biomolecular separation and characterization, which are indispensable towards understanding the biological and medical systems. Studying at the protein level allows researchers to investigate how proteins, their dynamics and modifications affect cellular processes and how cellular processes and the environment affect proteins. The mission of our facility is to provide excellent service and t...

  5. Resonance ionization mass spectrometry at Los Alamos National Laboratory

    International Nuclear Information System (INIS)

    Two approaches to Resonance Ionization Mass Spectrometry (RIMS) at Los Alamos National Laboratory are discussed. The first is the use of continuous-wave dye lasers as the ionization source, and the use of pulse counting detection; and results are presented for lutetium and technetium. The second approach is the use of multiphoton resonances in the pulsed laser excitation of atoms. Experiments with 2 + 1 [photons to resonance plus photons to ionize] RIMS schemes for several elements are discussed. (author)

  6. Extractive Electrospray Ionization Mass Spectrometry for Uranium Chemistry Studies

    OpenAIRE

    Chen, Huanwen; Luo, Mingbiao; Xiao, Saijin; OUYANG Yongzhong; Zhou, Yafei; Zhang, Xinglei

    2013-01-01

    Uranium chemistry is of sustainable interest. Breakthroughs in uranium studies make serious impacts in many fields including chemistry, physics, energy and biology, because uranium plays fundamentally important roles in these fields. Substantial progress in uranium studies normally requires development of novel analytical tools. Extractive electrospray ionization mass spectrometry (EESI-MS) is a sensitive technique for trace detection of various analytes in complex matrices without sample pre...

  7. Accelerator mass spectrometry for quantitative in vivo tracing

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, J S

    2005-04-19

    Accelerator mass spectrometry (AMS) counts individual rare, usually radio-, isotopes such as radiocarbon at high efficiency and specificity in milligram-sized samples. AMS traces very low chemical doses ({micro}g) and radiative doses (100 Bq) of isotope labeled compounds in animal models and directly in humans for pharmaceutical, nutritional, or toxicological research. Absorption, metabolism, distribution, binding, and elimination are all quantifiable with high precision after appropriate sample definition.

  8. Sheathless interface for coupling capillary electrophoresis with mass spectrometry

    Science.gov (United States)

    Wang, Chenchen; Tang, Keqi; Smith, Richard D.

    2014-06-17

    A sheathless interface for coupling capillary electrophoresis (CE) with mass spectrometry is disclosed. The sheathless interface includes a separation capillary for performing CE separation and an emitter capillary for electrospray ionization. A portion of the emitter capillary is porous or, alternatively, is coated to form an electrically conductive surface. A section of the emitter capillary is disposed within the separation capillary, forming a joint. A metal tube, containing a conductive liquid, encloses the joint.

  9. Evaluation of Physiological Amino Acids Profiling by Tandem Mass Spectrometry

    OpenAIRE

    Filee, Romain; Schoos, Roland; Boemer, François

    2013-01-01

    Background: Nowadays, the most conventional method to quantify physiological amino acids consists in ion exchange chromatography (IEC) followed by post-column ninhydrin derivatization and UV detection at two wavelengths. Unfortunately, the technique presents some drawbacks such as long run time, large sample volume, and specific costs associated to the maintenance of a dedicated instrument. Therefore, we aimed to switch towards a mass spectrometry approach.

  10. Report of the consultants' meeting on accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Accelerator Mass Spectrometry (AMS) has developed into a major analytical tool for the measurement of ultra-low-level long-lived radionuclides. Its use within the IAEA is recommended by the consultants in this meeting. The IAEA programs in which the technology would be useful and beneficial are: safeguards, physical and chemical sciences, human health, food and agriculture, radioactive waste management, radiation safety, industry and earth sciences

  11. Quality management in clinical application of mass spectrometry measurement systems.

    Science.gov (United States)

    Vogeser, Michael; Seger, Christoph

    2016-09-01

    Thanks to highly specific analyte detection and potentially complete compensation for matrix variables based on the principle of stable isotope derivative internal standardisation, mass spectrometry methods allow the development of diagnostic tests of outstanding analytical quality. However, these features per se do not guarantee reliability of tests. A wide range of factors can introduce analytical errors and inaccuracy due to the extreme complexity of the methods involved. Furthermore, it can be expected that the application patterns of MS methods in diagnostic laboratories will change substantially during the coming years - with presumably less specialised laboratories implementing mass spectrometry. Introduction of highly automated test solutions by manufacturers will require some trade-off between operation convenience, sample throughput and analytical performance. Structured and careful quality and risk management is therefore crucial to translate the analytical power of mass spectrometry into actionable and reliable results for individual patients' care and to maintain the degree of reliability that is expected from MS methods in clinical pathology. This reflection review discusses whether particular quality assurance tools have to be applied for MS-based diagnostic tests and whether these tools are different from those applied for optical- and affinity-based standard tests. Both pre-implementation strategies and surveillance of assays with assessment of metadata in routine testing are addressed. The release of the CLSI guideline C62-A in 2014 was a substantial achievement in this context because it addresses a wide spectrum of relevant issues in quality assurance of mass spectrometry-based clinical tests. However, the translation of this best practice document into individual laboratory settings is likely to be heterogeneous.

  12. Characterization of Enterobacteria using MALDI-TOF mass spectrometry.

    Science.gov (United States)

    Pribil, Patrick; Fenselau, Catherine

    2005-09-15

    A method is proposed for the rapid classification of Gram-negative Enterobacteria using on-slide solubilization and trypsin digestion of proteins, followed by MALDI-TOF MS analysis. Peptides were identified from tryptic digests using microsequencing by tandem mass spectrometry and database searches. Proteins from the outer membrane family (OMP) were consistently identified in the Enterobacteria Escherichia coli, Enterobacter cloacae, Erwinia herbicola, and Salmonella typhimurium. Database searches indicate that these OMP peptides observed are unique to the Enterobacteria order. PMID:16159146

  13. Cholesterol efflux analyses using stable isotopes and mass spectrometry

    OpenAIRE

    Robert J Brown; Shao, Fei; Baldán, Ángel; Albert, Carolyn J.; Ford, David A.

    2012-01-01

    Cholesterol efflux from macrophages and the vascular wall is the initial step of the cardiovascular protective reverse cholesterol transport process. This study demonstrates a mass spectrometry based assay to measure the cellular and media content of [d7]-cholesterol and unlabeled cholesterol that can be used to measure cholesterol efflux from cell lines. Using a triple quadrupole ESI-MS instrument in direct infusion mode, product ion scanning for m/z 83, neutral loss (NL) 375.5 scanning and ...

  14. Tissue Imaging Using Nanospray Desorption Electrospray Ionization Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Laskin, Julia; Heath, Brandi S.; Roach, Patrick J.; Cazares, Lisa H.; Semmes, O. John

    2012-01-03

    We present the first results showing the ambient imaging of biological samples in their native environment using nanospray desorption ionization (nanoDESI) mass spectrometry. NanoDESI is an ambient pressure ionization technique that enables precise control of ionization of molecules from substrates. We demonstrate highly sensitive and robust analysis of tissue samples with high spatial resolution (<12 {mu}m) without sample preparation, which will be essential for applications in clinical diagnostics, drug discovery, molecular biology, and biochemistry.

  15. Economics of tandem mass spectrometry screening of neonatal inherited disorders

    OpenAIRE

    Pandor, A; Eastham, J.; Chilcott, J.; Paisley, S; Beverley, C.

    2006-01-01

    Objectives: The aim of this study was to evaluate the cost-effectiveness of neonatal screening for phenylketonuria (PKU) and medium-chain acyl-coA dehydrogenase (MCAD) deficiency using tandem mass spectrometry (tandem MS). Methods: A systematic review of clinical efficacy evidence and cost-effectiveness modeling of screening in newborn infants within a UK National Health Service perspective was performed. Marginal costs, life-years gained, and cost-effectiveness acceptability curves are p...

  16. Mass Spectra of Individual Aerosol Particles Acquired During Intercepts of a Space Shuttle Exhaust Plume

    Science.gov (United States)

    Cziczo, D. J.; Cziczo, D. J.; Murphy, D. M.; Thomson, D. S.; Thomson, D. S.

    2001-12-01

    The WB-57 aircraft accomplished fourteen distinct stratospheric intercepts of the exhaust plume from a space shuttle during ACCENT 2000. Liftoff of the shuttle Atlantis for STS-106 occurred at 8:46 am local (12:46 UTC) with intercepts occurring from 5 to 90 minutes afterward. The Particle Analysis by Laser Mass Spectrometry (PALMS) instrument, mounted in the nose of the aircraft, was used to acquire individual mass spectra of over 2500 particles during these intercepts. The majority of positive mass spectra indicate the presence of the metals Al, Fe, Zn, Ga, and V, all components found in the solid rocket fuel. Organic material, presumably from binding and curing agents, was also present. Negative mass spectra showed Cl from the oxidizer, ammonium perchlorate, as well as water. Rare exotic particles, for example those containing Ti and Ag and possibly formed during engine or seal ablation, were also detected. Particles originating from shuttle exhaust but also containing significant sulfuric acid were common toward the outer edge of the plume, especially during late encounters, suggesting that deposition or aerosol collision had occurred.

  17. Significant advancement of mass spectrometry imaging for food chemistry.

    Science.gov (United States)

    Yoshimura, Yukihiro; Goto-Inoue, Naoko; Moriyama, Tatsuya; Zaima, Nobuhiro

    2016-11-01

    Food contains various compounds that have an impact on our daily lives. Many technologies have been established to analyze these molecules of interest in foods. However, the analysis of the spatial distribution of these compounds in foods using conventional technology, such as high-performance liquid chromatography-mass spectrometry or gas chromatography-mass spectrometry is difficult. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is considered an ideal complementary approach. MALDI-MSI is a two-dimensional MALDI-MS technology that can detect compounds in a tissue section without extraction, purification, separation, or labeling. MALDI-MSI can be used to visualize the spatial distribution of chemical compounds or biomolecules in foods. Although the methodology of MALDI-MSI in food science is not yet fully established, the versatility of MALDI-MSI is expected to open a new frontier in food science. Herein, we describe the principles and applications of MALDI-MSI in food science and related fields. PMID:27211639

  18. Significant advancement of mass spectrometry imaging for food chemistry.

    Science.gov (United States)

    Yoshimura, Yukihiro; Goto-Inoue, Naoko; Moriyama, Tatsuya; Zaima, Nobuhiro

    2016-11-01

    Food contains various compounds that have an impact on our daily lives. Many technologies have been established to analyze these molecules of interest in foods. However, the analysis of the spatial distribution of these compounds in foods using conventional technology, such as high-performance liquid chromatography-mass spectrometry or gas chromatography-mass spectrometry is difficult. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is considered an ideal complementary approach. MALDI-MSI is a two-dimensional MALDI-MS technology that can detect compounds in a tissue section without extraction, purification, separation, or labeling. MALDI-MSI can be used to visualize the spatial distribution of chemical compounds or biomolecules in foods. Although the methodology of MALDI-MSI in food science is not yet fully established, the versatility of MALDI-MSI is expected to open a new frontier in food science. Herein, we describe the principles and applications of MALDI-MSI in food science and related fields.

  19. History of mass spectrometry at the Olympic Games.

    Science.gov (United States)

    Hemmersbach, Peter

    2008-07-01

    Mass spectrometry has played a decisive role in doping analysis and doping control in human sport for almost 40 years. The standard of qualitative and quantitative determinations in body fluids has always attracted maximum attention from scientists. With its unique sensitivity and selectivity properties, mass spectrometry provides state-of-the-art technology in analytical chemistry. Both anti-doping organizations and the athletes concerned expect the utmost endeavours to prevent false-positive and false-negative results of the analytical evidence. The Olympic Games play an important role in international sport today and are milestones for technical development in doping analysis. This review of the part played by mass spectrometry in doping control from Munich 1972 to Beijing 2008 Olympics gives an overview of how doping analysis has developed and where we are today. In recognizing the achievements made towards effective doping control, it is of the utmost importance to applaud the joint endeavours of the World Anti-Doping Agency, the International Olympic Committee, the international federations and national anti-doping agencies to combat doping. Advances against the misuse of prohibited substances and methods, which are performance-enhancing, dangerous to health and violate the spirit of sport, can be achieved only if all the stakeholders work together.

  20. SVSCf plasma desorption mass spectrometry: recent advances and applications

    Energy Technology Data Exchange (ETDEWEB)

    Kamensky, I.; Craig, A.G.

    1987-01-01

    SVSCf plasma desorption mass spectrometry (PDMS) as utilized in the BIO-ION instruments is described. The sensitivity of the technique is investigated for varying amounts of bovine insulin. The results show accurate mass assignment for pmole amounts of sample. Several methods, currently used for sample preparation in PDMS, are described. Spectra of the antibiotic nisin using two different sample preparation techniques show significant variation. The fragmentation pattern of reduced acetylated maltoheptaose is also presented. The initial results obtained using a new PDMS instrument equipped with variable flight path are shown. The increased resolution is illustrated using the extended flight path to measure the molecular ion region of the maltoheptaose.

  1. Studies in biogenic amine metabolism by mass spectrometry

    International Nuclear Information System (INIS)

    Two areas of mass spectral study related to biogenic amine metabolism are presented: The use of electron capture negative ion chemical ionization mass spectrometry for the quantitation of melatonin and other indole amines, and general synthetic procedures useful for the synthesis of deuterated diazomethane and deuteromethylated catechols. The factors determining instrumental sensitivity in negative ion chemical ionization are discussed, and the enhancement of the primary ion beam using magnetic fields is described. Quantitation of human plasma melatonin at the parts per trillion or pg/ml level has been demonstrated and is routinely performed as a selected ion monitoring assay. (Auth.)

  2. Tissue MALDI Mass Spectrometry Imaging (MALDI MSI) of Peptides.

    Science.gov (United States)

    Beine, Birte; Diehl, Hanna C; Meyer, Helmut E; Henkel, Corinna

    2016-01-01

    Matrix assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) is a technique to visualize molecular features of tissues based on mass detection. This chapter focuses on MALDI MSI of peptides and provides detailed operational instructions for sample preparation of cryoconserved and formalin-fixed paraffin-embedded (FFPE) tissue. Besides sample preparation we provide protocols for the MALDI measurement, tissue staining, and data analysis. On-tissue digestion and matrix application are described for two different commercially available and commonly used spraying devices: the SunCollect (SunChrom) and the ImagePrep (Bruker Daltonik GmbH).

  3. Characterization of individual particles in gaseous media by mass spectrometry

    Science.gov (United States)

    Sinha, M. P.

    1990-01-01

    An introduction is given to a system for particle analysis by mass spectrometry (PAMS) which employs particle-beam techniques to measure mass spectra on a continuous real-time basis. The system is applied to particles of both organic and inorganic compounds, and the measurements give the chemical characteristics of particles in mixtures and indicate source apportionment. The PAMS system can be used for process control and studying heterogeneous/catalytic reactions in particles, and can be fitted to study the real-time attributes of PAMS.

  4. Mass-spectrometric identification of primary biological particle markers: indication for low abundance of primary biological material in the pristine submicron aerosol of Amazonia

    Directory of Open Access Journals (Sweden)

    J. Schneider

    2011-07-01

    Full Text Available The abundance of marker compounds for primary biological particles in submicron aerosol was investigated by means of aerosol mass spectrometry. Mass spectra of amino acids, carbohydrates, small peptides, and proteins, all of which are key building blocks of biological particles, were recorded in laboratory experiments. Several characteristic marker peaks were identified. The identified marker peaks were compared with mass spectra recorded during AMAZE-08, a field campaign conducted in the pristine rainforest of the Central Amazon Basin, Brazil, during the wet season of February and March 2008. The low abundance of identified marker peaks places upper limits of 7.5 % for amino acids and 5.6 % for carbohydrates on the contribution of primary biological aerosol particles (PBAPs to the submicron organic aerosol mass concentration during this time period. Upper limits for the absolute submicron concentrations for both compound classes range from 0.01 to 0.1 μg m−3. Carbohydrates and protein amino acids make up for about two thirds of the dry mass of a biological cell. Thus, our findings suggest an upper limit for the PBAPs mass fraction of about 20 % to the submicron organic aerosol.

  5. Measurement of the 135Cs half-life with accelerator mass spectrometry and inductively coupled plasma mass spectrometry

    Science.gov (United States)

    MacDonald, C. M.; Cornett, R. J.; Charles, C. R. J.; Zhao, X. L.; Kieser, W. E.

    2016-01-01

    The isotope 135Cs is quoted as having a half-life of 2.3 Myr. However, there are three published values ranging from 1.8 to 3 Myr. This research reviews previous measurements and reports a new measurement of the half-life using newly developed accelerator mass spectrometry (AMS) and inductively coupled plasma mass spectrometry (ICPMS) techniques along with β and γ radiometric analysis. The half-life was determined to be (1.6 ±0.6 ) ×106 yr by AMS and (1.3 ±0.2 ) ×106 yr by ICPMS with 95% confidence. The two values agree with each other but differ from the accepted value by ˜40 % .

  6. Neuropeptide Signaling in Crustaceans Probed by Mass Spectrometry

    Science.gov (United States)

    Liang, Zhidan

    Neuropeptides are one of the most diverse classes of signaling molecules whose identities and functions are not yet fully understood. They have been implicated in the regulation of a wide range of physiological processes, including feeding-related and motivated behaviors, and also environmental adaptations. In this work, improved mass spectrometry-based analytical platforms were developed and applied to the crustacean systems to characterize signaling molecules. This dissertation begins with a review of mass spectrometry-based neuropeptide studies from both temporal- and spatial-domains. This review is then followed by several chapters detailing a few research projects related to the crustacean neuropeptidomic characterization and comparative analysis. The neuropeptidome of crayfish, Orconectes rusticus is characterized for the first time using mass spectrometry-based tools. In vivo microdialysis sampling technique offers the capability of direct sampling from extracellular space in a time-resolved manner. It is used to investigate the secreted neuropeptide and neurotransmitter content in Jonah crab, Cancer borealis, in this work. A new quantitation strategy using alternative mass spectrometry data acquisition approach is developed and applied for the first time to quantify neuropeptides. Coupling of this method with microdialysis enables the study of neuropeptide dynamics concurrent with different behaviors. Proof-of-principle experiments validating this approach have been carried out in Jonah crab, Cancer borealis to study feeding- and circadian rhythm-related neuropeptide changes using micoridialysis in a time-resolved manner. This permits a close correlation between behavioral and neurochemical changes, providing potential candidates for future validation of regulatory roles. In addition to providing spatial information, mass spectrometry imaging (MSI) technique enables the characterization of signaling molecules while preserving the temporal resolution. A

  7. Inductively Coupled Plasma: Fundamental Particle Investigations with Laser Ablation and Applications in Magnetic Sector Mass Spectrometry

    International Nuclear Information System (INIS)

    Particle size effects and elemental fractionation in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are investigated with nanosecond and femtosecond laser ablation, differential mobility analysis, and magnetic sector ICP-MS. Laser pulse width was found to have a significant influence on the LA particle size distribution and the elemental composition of the aerosol and thus fractionation. Emission from individual particles from solution nebulization, glass, and a pressed powder pellet are observed with high speed digital photography. The presence of intact particles in an ICP is shown to be a likely source of fractionation. A technique for the online detection of stimulated elemental release from neural tissue using magnetic sector ICP-MS is described. Detection limits of 1 (micro)g L-1 or better were found for P, Mn, Fe, Cu, and Zn in a 60 (micro)L injection in a physiological saline matrix

  8. Inductively Coupled Plasma: Fundamental Particle Investigations with Laser Ablation and Applications in Magnetic Sector Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Saetveit, Nathan Joe [Iowa State Univ., Ames, IA (United States)

    2008-01-01

    Particle size effects and elemental fractionation in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are investigated with nanosecond and femtosecond laser ablation, differential mobility analysis, and magnetic sector ICP-MS. Laser pulse width was found to have a significant influence on the LA particle size distribution and the elemental composition of the aerosol and thus fractionation. Emission from individual particles from solution nebulization, glass, and a pressed powder pellet are observed with high speed digital photography. The presence of intact particles in an ICP is shown to be a likely source of fractionation. A technique for the online detection of stimulated elemental release from neural tissue using magnetic sector ICP-MS is described. Detection limits of 1 μg L-1 or better were found for P, Mn, Fe, Cu, and Zn in a 60 μL injection in a physiological saline matrix.

  9. Analysis of aromatic hydrocarbons in petroleum fractions using gas chromatography, mass spectrometry and mass fragmentrography

    Energy Technology Data Exchange (ETDEWEB)

    Kubelka, V.

    1980-01-01

    Mass spectrometry in combination with gas chrom. used to analyze hydrocarbon mixtures results in qualit. and semi-quant. data regarding composition of the analyzed mixture. Use of mass fragmentrography during chromatographic separation will allow simultaneous recording of changes in intensity of characteristic ions and thus determine the retention index, for this substance. Combining mass spectre and retention index, it is possible to identify the given subst. or limit the number of possible combinations.

  10. Potential of needle trap microextraction-portable gas chromatography-mass spectrometry for measurement of atmospheric volatile compounds

    Science.gov (United States)

    Feijó Barreira, Luís Miguel; Xue, Yu; Duporté, Geoffroy; Parshintsev, Jevgeni; Hartonen, Kari; Jussila, Matti; Kulmala, Markku; Riekkola, Marja-Liisa

    2016-08-01

    Volatile organic compounds (VOCs) play a key role in atmospheric chemistry and physics. They participate in photochemical reactions in the atmosphere, which have direct implications on climate through, e.g. aerosol particle formation. Forests are important sources of VOCs, and the limited resources and infrastructures often found in many remote environments call for the development of portable devices. In this research, the potential of needle trap microextraction and portable gas chromatography-mass spectrometry for the study of VOCs at forest site was evaluated. Measurements were performed in summer and autumn 2014 at the Station for Measuring Ecosystem-Atmosphere Relations (SMEAR II) in Hyytiälä, Finland. During the first part of the campaign (summer) the applicability of the developed method was tested for the determination of monoterpenes, pinonaldehyde, aldehydes, amines and anthropogenic compounds. The temporal variation of aerosol precursors was determined, and evaluated against temperature and aerosol number concentration data. The most abundant monoterpenes, pinonaldehyde and aldehydes were successfully measured, their relative amounts being lower during days when particle number concentration was higher. Ethylbenzene, p- and m-xylene were also found when wind direction was from cities with substantial anthropogenic activity. An accumulation of VOCs in the snow cover was observed in the autumn campaign. Results demonstrated the successful applicability of needle trap microextraction and portable gas chromatography-mass spectrometry for the rapid in situ determination of organic gaseous compounds in the atmosphere.

  11. Carboxylic acid functional group analysis using constant neutral loss scanning-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dron, Julien [Laboratoire de Chimie et Environnement, Marseille Universites (case 29), 3 place Victor Hugo, 13331 Marseille Cedex 3 (France)], E-mail: julien.dron@up.univ-mrs.fr; Eyglunent, Gregory; Temime-Roussel, Brice; Marchand, Nicolas; Wortham, Henri [Laboratoire de Chimie et Environnement, Marseille Universites (case 29), 3 place Victor Hugo, 13331 Marseille Cedex 3 (France)

    2007-12-12

    The present study describes the development of a new analytical technique for the functional group determination of the carboxylic moiety using atmospheric pressure chemical ionization-mass spectrometry (APCI-MS/MS) operated in the constant neutral loss scanning (CNLS) mode. Carboxylic groups were first derivatized into their corresponding methyl esters by reacting with BF{sub 3}/methanol mix and the reaction mixture was then directly injected into the APCI chamber. The loss of methanol (m/z = 32 amu) resulting from the fragmentation of the protonated methyl esters was then monitored. Applying this method together with a statistical approach to reference mixtures containing 31 different carboxylic acids at randomly calculated concentrations demonstrated its suitability for quantitative functional group measurements with relative standard deviations below 15% and a detection limit of 0.005 mmol L{sup -1}. Its applicability to environmental matrices was also shown through the determination of carboxylic acid concentrations inside atmospheric aerosol samples. To the best of our knowledge, it is the first time that the tandem mass spectrometry was successfully applied to functional group analysis, offering great perspectives in the characterization of complex mixtures which are prevailing in the field of environmental analysis as well as in the understanding of the chemical processes occurring in these matrices.

  12. Imaging MALDI mass spectrometry of sphingolipids using an oscillating capillary nebulizer matrix application system.

    Science.gov (United States)

    Chen, Yanfeng; Liu, Ying; Allegood, Jeremy; Wang, Elaine; Cachón-González, Begoña; Cox, Timothy M; Merrill, Alfred H; Sullards, M Cameron

    2010-01-01

    Matrix deposition is a critical step in tissue imaging by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). It greatly affects the quality of MALDI imaging, especially for the analytes (such as lipids) that may easily dissolve in the solvent used for the matrix application. This chapter describes the use of an oscillating capillary nebulizer (OCN) to spray small droplets of matrix aerosol onto the sample surface for improved matrix homogeneity, reduced crystal size, and controlled solvent effects. This protocol allows visualization of many different lipid species and, of particular interest, sphingolipids in tissue slices of Tay-Sachs/Sandhoff disease by imaging MALDI-MS. The structures of these lipids were identified by analysis of tissue extracts using electrospray ionization in conjunction with tandem mass spectrometry (MS/MS and MS(3)). These results illustrate the usefulness of tissue imaging MALDI-MS with matrix deposition by OCN for the molecular analysis in normal physiology and pathology. In addition, the observation of numerous lipid subclasses with distinct localizations in the brain slices demonstrates that imaging MALDI-MS could be effectively used for "lipidomic" studies. PMID:20680588

  13. Mass spectrometry improvement on an high current ion implanter

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, J.G., E-mail: jgabriel@deea.isel.ipl.pt [Instituto Superior de Engenharia de Lisboa and Centro de Fisica Nuclear of the University of Lisbon, Rua Conselheiro Emidio Navarro, 1, 1959-007 Lisbon (Portugal); Alegria, F.C., E-mail: falegria@lx.it.pt [Instituto Superior Tecnico/Technical University of Lisbon and Instituto de Telecomunicacoes, Av. Rovisco Pais, 1, 1049-001 Lisbon (Portugal); Redondo, L.M., E-mail: lmredondo@deea.isel.ipl.pt [Instituto Superior de Engenharia de Lisboa and Centro de Fisica Nuclear of the University of Lisbon, Rua Conselheiro Emidio Navarro, 1, 1959-007 Lisbon (Portugal); Rocha, J., E-mail: jrocha@itn.pt [Instituto Tecnologico Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Alves, E., E-mail: ealves@itn.pt [Instituto Tecnologico Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal)

    2011-12-15

    The development of accurate mass spectrometry, enabling the identification of all the ions extracted from the ion source in a high current implanter is described. The spectrometry system uses two signals (x-y graphic), one proportional to the magnetic field (x-axes), taken from the high-voltage potential with an optic fiber system, and the other proportional to the beam current intensity (y-axes), taken from a beam-stop. The ion beam mass register in a mass spectrum of all the elements magnetically analyzed with the same radius and defined by a pair of analyzing slits as a function of their beam intensity is presented. The developed system uses a PC to control the displaying of the extracted beam mass spectrum, and also recording of all data acquired for posterior analysis. The operator uses a LabVIEW code that enables the interfacing between an I/O board and the ion implanter. The experimental results from an ion implantation experiment are shown.

  14. Quantitative mass spectrometry of unconventional human biological matrices

    Science.gov (United States)

    Dutkiewicz, Ewelina P.; Urban, Pawel L.

    2016-10-01

    The development of sensitive and versatile mass spectrometric methodology has fuelled interest in the analysis of metabolites and drugs in unconventional biological specimens. Here, we discuss the analysis of eight human matrices-hair, nail, breath, saliva, tears, meibum, nasal mucus and skin excretions (including sweat)-by mass spectrometry (MS). The use of such specimens brings a number of advantages, the most important being non-invasive sampling, the limited risk of adulteration and the ability to obtain information that complements blood and urine tests. The most often studied matrices are hair, breath and saliva. This review primarily focuses on endogenous (e.g. potential biomarkers, hormones) and exogenous (e.g. drugs, environmental contaminants) small molecules. The majority of analytical methods used chromatographic separation prior to MS; however, such a hyphenated methodology greatly limits analytical throughput. On the other hand, the mass spectrometric methods that exclude chromatographic separation are fast but suffer from matrix interferences. To enable development of quantitative assays for unconventional matrices, it is desirable to standardize the protocols for the analysis of each specimen and create appropriate certified reference materials. Overcoming these challenges will make analysis of unconventional human biological matrices more common in a clinical setting. This article is part of the themed issue 'Quantitative mass spectrometry'.

  15. Lipidomic mass spectrometry and its application in neuroscience

    Institute of Scientific and Technical Information of China (English)

    Mabel; Enriquez-Algeciras; Sanjoy; K; Bhattacharya

    2013-01-01

    Central and peripheral nervous systems are lipid rich tissues. Lipids, in the context of lipid-protein complexes, surround neurons and provide electrical insulation for transmission of signals allowing neurons to remain embedded within a conducting environment. Lipids play a key role in vesicle formation and fusion in synapses. They provide means of rapid signaling, cell motility and migration for astrocytes and other cell types that surround and play supporting roles neurons. Unlike many other signaling molecules, lipids are capable of multiple signaling events based on the different fragments generated from a single precursor during each event. Lipidomics, until recently suffered from two major disadvantages:(1) level of expertise required an overwhelming amount of chemical detail to correctly identify a vast number of different lipids which could be close in their chemical reactivity; and(2) high amount of purified compounds needed by analytical techniques to determine their structures. Advances in mass spectrometry have enabled overcoming these two limitations. Mass spectrometry offers a great degree of simplicity in identification and quantification of lipids directly extracted from complex biological mixtures. Mass spectrometers can be regarded to as mass analyzers. There are those that separate and analyze the product ion fragments in space(spatial) and those which separate product ions in time in the same space(temporal). Databases and standardized instrument parameters have further aided the capabilities of the spatial instruments while recent advances in bioinformatics have made the identification and quantification possible using temporal instruments.

  16. Study of coal structure using secondary ion mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tingey, G.L.; Lytle, J.M.; Baer, D.R.; Thomas, M.T.

    1980-12-01

    Secondary-ion Mass Spectrometry (SIMS) is examined as a tool for studying the chemical structure of coal. SIMS has potential for analysis of coal because of the following characteristics: sensitivity to chemical structure; high sensitivity to all masses; application to solids; excellent depth resolution; and reasonable spatial resolution. SIMS spectra of solid coals show differences with respect to coal rank, the spectra of high rank coal being similar to that of graphite, and the spectra of low rank coal being similar to that of wood. Some functional group analysis is also possible using SIMS. Low rank coals show a larger peak at 15 amu indicating more methyl groups than found in the higher rank coals. Fragments with two and three carbon atoms have also been examined; much larger fragments are undoubtedly present but were not evaluated in this study. Examination of these groups, which are expected to contain valuable information on coal structure, is planned for future work. It has been observed that mineral atoms present in the coal have large secondary ion yields which complicate the interpretation of the spectra. Studies on mineral-free coals and model compounds are therefore recommended to facilitate determination of organic coal structure. In addition, mass spectrometry with much greater mass resolution will aid in distinguishing between various ion species.

  17. Exploring the high-mass components of humic acid by laser desorption ionization mass spectrometry.

    Science.gov (United States)

    Chilom, Gabriela; Chilom, Ovidiu; Rice, James A

    2008-05-01

    Leonardite and Elliot soil humic acids have been analyzed by laser desorption ionization mass spectrometry (LDI MS) in the m/z 4000-200,000 range. Positive ion mass spectra for each humic acid obtained under optimum conditions showed a broad high-mass distribution between m/z 20,000 and 80,000. The dependence of the mass distribution on instrumental parameters and solution conditions was used to investigate the nature of the high-mass peaks from humic acid spectra. Our data suggests that macromolecular ions and humic acid aggregates have the same probability of occurrence while cluster ion formation has a low probability of occurrence. PMID:18421699

  18. Characterization and source apportionment of submicron aerosol with aerosol mass spectrometer during the PRIDE-PRD 2006 campaign

    Science.gov (United States)

    Xiao, R.; Takegawa, N.; Zheng, M.; Kondo, Y.; Miyazaki, Y.; Miyakawa, T.; Hu, M.; Shao, M.; Zeng, L.; Gong, Y.; Lu, K.; Deng, Z.; Zhao, Y.; Zhang, Y. H.

    2011-07-01

    Size-resolved chemical compositions of non-refractory submicron aerosol were measured using an Aerodyne quadrupole aerosol mass spectrometer (Q-AMS) at the rural site Back Garden (BG), located ~50 km northwest of Guangzhou in July 2006. This paper characterized the submicron aerosol particles of regional air pollution in Pearl River Delta (PRD) in the southern China. Organics and sulfate dominated the submicron aerosol compositions, with average mass concentrations of 11.8 ± 8.4 μg m-3 and 13.5 ± 8.7 μg m-3, respectively. Unlike other air masses, the air masses originated from Southeast-South and passing through the PRD urban areas exhibited distinct bimodal size distribution characteristics for both organics and sulfate: the first mode peaked at vacuum aerodynamic diameters (Dva) ∼200 nm and the second mode occurred at Dva from 300-700 nm. With the information from AMS, it was found from this study that the first mode of organics in PRD regional air masses was contributed by both secondary organic aerosol formation and combustion-related emissions, which is different from most findings in other urban areas (first mode of organics primarily from combustion-related emissions). The analysis of AMS mass spectra data by positive matrix factorization (PMF) model identified three sources of submicron organic aerosol including hydrocarbon-like organic aerosol (HOA), low volatility oxygenated organic aerosol (LV-OOA) and semi-volatile oxygenated organic aerosol (SV-OOA). The strong correlation between HOA and EC indicated primary combustion emissions as the major source of HOA while a close correlation between SV-OOA and semi-volatile secondary species nitrate as well as between LV-OOA and nonvolatile secondary species sulfate suggested secondary aerosol formation as the major source of SV-OOA and LV-OOA at the BG site. However, LV-OOA was more aged than SV-OOA as its spectra was highly correlated with the reference spectra of fulvic acid, an indicator of aged and

  19. Intact MicroRNA Analysis Using High Resolution Mass Spectrometry

    Science.gov (United States)

    Kullolli, Majlinda; Knouf, Emily; Arampatzidou, Maria; Tewari, Muneesh; Pitteri, Sharon J.

    2014-01-01

    MicroRNAs (miRNAs) are small single-stranded non-coding RNAs that post-transcriptionally regulate gene expression, and play key roles in the regulation of a variety of cellular processes and in disease. New tools to analyze miRNAs will add understanding of the physiological origins and biological functions of this class of molecules. In this study, we investigate the utility of high resolution mass spectrometry for the analysis of miRNAs through proof-of-concept experiments. We demonstrate the ability of mass spectrometry to resolve and separate miRNAs and corresponding 3' variants in mixtures. The mass accuracy of the monoisotopic deprotonated peaks from various miRNAs is in the low ppm range. We compare fragmentation of miRNA by collision-induced dissociation (CID) and by higher-energy collisional dissociation (HCD) which yields similar sequence coverage from both methods but additional fragmentation by HCD versus CID. We measure the linear dynamic range, limit of detection, and limit of quantitation of miRNA loaded onto a C18 column. Lastly, we explore the use of data-dependent acquisition of MS/MS spectra of miRNA during online LC-MS and demonstrate that multiple charge states can be fragmented, yielding nearly full sequence coverage of miRNA on a chromatographic time scale. We conclude that high resolution mass spectrometry allows the separation and measurement of miRNAs in mixtures and a standard LC-MS setup can be adapted for online analysis of these molecules.

  20. Characterizing uranium oxide reference particles for isotopic abundances and uranium mass by single particle isotope dilution mass spectrometry

    International Nuclear Information System (INIS)

    Highlights: ► A method to quantify the U mass in single micron particles by ID-TIMS was developed. ► Well-characterized monodisperse U-oxide particles produced by an aerosol generator were used. ► A linear correlation between the mass of U and the volume of particle(s) was found. ► The method developed is suitable for determining the amount of U in a particulate reference material. - Abstract: Uranium and plutonium particulate test materials are becoming increasingly important as the reliability of measurement results has to be demonstrated to regulatory bodies responsible for maintaining effective nuclear safeguards. In order to address this issue, the Institute for Reference Materials and Measurements (IRMM) in collaboration with the Institute for Transuranium Elements (ITU) has initiated a study to investigate the feasibility of preparing and characterizing a uranium particle reference material for nuclear safeguards, which is finally certified for isotopic abundances and for the uranium mass per particle. Such control particles are specifically required to evaluate responses of instruments based on mass spectrometric detection (e.g. SIMS, TIMS, LA-ICPMS) and to help ensuring the reliability and comparability of measurement results worldwide. In this paper, a methodology is described which allows quantifying the uranium mass in single micron particles by isotope dilution thermal ionization mass spectrometry (ID-TIMS). This methodology is characterized by substantial improvements recently achieved at IRMM in terms of sensitivity and measurement accuracy in the field of uranium particle analysis by TIMS. The use of monodisperse uranium oxide particles prepared using an aerosol generation technique developed at ITU, which is capable of producing particles of well-characterized size and isotopic composition was exploited. The evidence of a straightforward correlation between the particle volume and the mass of uranium was demonstrated in this study

  1. Development of ion-mobility and mass spectrometry for probing the reactivity of nanoparticles and nanocomposites

    Science.gov (United States)

    Zhou, Lei

    2009-12-01

    Aerosols of diameter smaller than 100 nm, usually are referred as nanoparticles or ultrafines, have received considerable interests lately as a source of building blocks to novel materials. However, our capabilities for charactering these materials are greatly limited by lack of appropriate diagnostic tools. The objective of this work is to develop new aerosol-based techniques for the characterization of nanoparticles and nanocomposites. Though the scope of this dissertation is focused on probing the reactivity of metal based nanoparticles/nanocomposites and their applications in energetic materials, the methods provide generic approaches for understanding the intrinsic reactivity of nanoparticles. Real-time single particle mass spectrometry (SPMS) has been used to study the reactivity of aluminum nanoparticles. The SPMS is a powerful tool due to its ability to obtain quantitative information at the single particle level. Here in this work, we conducted extensive investigations on the quantification of the SPMS. Particle morphology and composition biases on quantifying the composition of nanoparticles were observed experimentally, was related to the high non-linear properties of the laser-particle interaction. To understand pulsed laser interaction with nanoparticles, as it applied to the implementation and quantification of SPMS, we employed a one-dimensional hydrodynamic model to determine the characteristic behavior of ions produced from the particle. In the simulation, the temporal evolution of the ionization state and energy were evaluated as a function of aluminum particle size that were heated and ionized by a nanosecond laser. The results are shown to be consistent with our experimental observation, and suggest that particle size-dependent energetic ions led to the power law relationship between peak area and particle size observed in our single particle mass spectrometer. Another approach to probe the reactivity of the nanoparticles is an ion

  2. Mass analysis of charged aerosol particles in NLC and PMSE during the ECOMA/MASS campaign

    Directory of Open Access Journals (Sweden)

    S. Robertson

    2009-03-01

    Full Text Available MASS (Mesospheric Aerosol Sampling Spectrometer is a multichannel mass spectrometer for charged aerosol particles, which was flown from the Andøya Rocket Range, Norway, through NLC and PMSE on 3 August 2007 and through PMSE on 6 August 2007. The eight-channel analyzers provided for the first time simultaneous measurements of the charge density residing on aerosol particles in four mass ranges, corresponding to ice particles with radii <0.5 nm (including ions, 0.5–1 nm, 1–2 nm, and >3 nm (approximately. Positive and negative particles were recorded on separate channels. Faraday rotation measurements provided electron density and a means of checking charge density measurements made by the spectrometer. Additional complementary measurements were made by rocket-borne dust impact detectors, electric field booms, a photometer and ground-based radar and lidar. The MASS data from the first flight showed negative charge number densities of 1500–3000 cm−3 for particles with radii >3 nm from 83–88 km approximately coincident with PMSE observed by the ALWIN radar and NLC observed by the ALOMAR lidar. For particles in the 1–2 nm range, number densities of positive and negative charge were similar in magnitude (~2000 cm−3 and for smaller particles, 0.5–1 nm in radius, positive charge was dominant. The occurrence of positive charge on the aerosol particles of the smallest size and predominately negative charge on the particles of largest size suggests that nucleation occurs on positive condensation nuclei and is followed by collection of negative charge during subsequent growth to larger size. Faraday rotation measurements show a bite-out in electron density that increases the time for positive aerosol particles to be neutralized and charged negatively. The larger particles (>3 nm are observed throughout the NLC region, 83–88 km, and the smaller particles are observed primarily at the high end of the range, 86–88 km

  3. Rapid identification of DNA-binding proteins by mass spectrometry

    DEFF Research Database (Denmark)

    Nordhoff, E; Krogsdam, A M; Jorgensen, H F;

    1999-01-01

    We report a protocol for the rapid identification of DNA-binding proteins. Immobilized DNA probes harboring a specific sequence motif are incubated with cell or nuclear extract. Proteins are analyzed directly off the solid support by matrix-assisted laser desorption/ionization time-of-flight mass...... spectrometry. The determined molecular masses are often sufficient for identification. If not, the proteins are subjected to mass spectrometric peptide mapping followed by database searches. Apart from protein identification, the protocol also yields information on posttranslational modifications. The protocol...... was validated by the identification of known prokaryotic and eukaryotic DNA-binding proteins, and its use provided evidence that poly(ADP-ribose) polymerase exhibits DNA sequence-specific binding to DNA....

  4. Combustion chemistry of energetic materials studied by probing mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Korobeinichev, O.P.; Kuibida, L.V.; Paletsky, A.A.; Shmakov, A.G. [Russian Academy of Sciences, Novosibirsk (Russian Federation). Inst. of Chemical Kinetics and Combustion

    1996-07-01

    The methods of probing mass spectrometry (PMS) for diagnostic of flames and for the study of kinetics and mechanism of the thermal decomposition products of energetic materials (EM) are described. Several types of instruments based on microprobe and molecular beam mass spectrometric sampling have been developed. Time of flight mass spectrometer has been used. Apparatuses for high (10 atm) and low (<1 atm) pressure have been developed for the study of combustion and decomposition of EM by PMS ``in situ.`` Several examples are presented to demonstrate application of PMS method for the study of EM flame structure, thermal decomposition and dynamic of ignition. Experimental data on decomposition of double base propellants ammonium dinitramide, ammonium perchlorate are presented.

  5. Fourier transform ion cyclotron resonance mass spectrometry: a primer.

    Science.gov (United States)

    Marshall, A G; Hendrickson, C L; Jackson, G S

    1998-01-01

    This review offers an introduction to the principles and generic applications of FT-ICR mass spectrometry, directed to readers with no prior experience with the technique. We are able to explain the fundamental FT-ICR phenomena from a simplified theoretical treatment of ion behavior in idealized magnetic and electric fields. The effects of trapping voltage, trap size and shape, and other nonidealities are manifested mainly as perturbations that preserve the idealized ion behavior modified by appropriate numerical correction factors. Topics include: effect of ion mass, charge, magnetic field, and trapping voltage on ion cyclotron frequency; excitation and detection of ICR signals; mass calibration; mass resolving power and mass accuracy; upper mass limit(s); dynamic range; detection limit, strategies for mass and energy selection for MSn; ion axialization, cooling, and remeasurement; and means for guiding externally formed ions into the ion trap. The relation of FT-ICR MS to other types of Fourier transform spectroscopy and to the Paul (quadrupole) ion trap is described. The article concludes with selected applications, an appendix listing accurate fundamental constants needed for ultrahigh-precision analysis, and an annotated list of selected reviews and primary source publications that describe in further detail various FT-ICR MS techniques and applications.

  6. Two-Dimensional Aperture Coding for Magnetic Sector Mass Spectrometry

    Science.gov (United States)

    Russell, Zachary E.; Chen, Evan X.; Amsden, Jason J.; Wolter, Scott D.; Danell, Ryan M.; Parker, Charles B.; Stoner, Brian R.; Gehm, Michael E.; Brady, David J.; Glass, Jeffrey T.

    2015-02-01

    In mass spectrometer design, there has been a historic belief that there exists a fundamental trade-off between instrument size, throughput, and resolution. When miniaturizing a traditional system, performance loss in either resolution or throughput would be expected. However, in optical spectroscopy, both one-dimensional (1D) and two-dimensional (2D) aperture coding have been used for many years to break a similar trade-off. To provide a viable path to miniaturization for harsh environment field applications, we are investigating similar concepts in sector mass spectrometry. Recently, we demonstrated the viability of 1D aperture coding and here we provide a first investigation of 2D coding. In coded optical spectroscopy, 2D coding is preferred because of increased measurement diversity for improved conditioning and robustness of the result. To investigate its viability in mass spectrometry, analytes of argon, acetone, and ethanol were detected using a custom 90-degree magnetic sector mass spectrometer incorporating 2D coded apertures. We developed a mathematical forward model and reconstruction algorithm to successfully reconstruct the mass spectra from the 2D spatially coded ion positions. This 2D coding enabled a 3.5× throughput increase with minimal decrease in resolution. Several challenges were overcome in the mass spectrometer design to enable this coding, including the need for large uniform ion flux, a wide gap magnetic sector that maintains field uniformity, and a high resolution 2D detection system for ion imaging. Furthermore, micro-fabricated 2D coded apertures incorporating support structures were developed to provide a viable design that allowed ion transmission through the open elements of the code.

  7. Two-dimensional aperture coding for magnetic sector mass spectrometry.

    Science.gov (United States)

    Russell, Zachary E; Chen, Evan X; Amsden, Jason J; Wolter, Scott D; Danell, Ryan M; Parker, Charles B; Stoner, Brian R; Gehm, Michael E; Brady, David J; Glass, Jeffrey T

    2015-02-01

    In mass spectrometer design, there has been a historic belief that there exists a fundamental trade-off between instrument size, throughput, and resolution. When miniaturizing a traditional system, performance loss in either resolution or throughput would be expected. However, in optical spectroscopy, both one-dimensional (1D) and two-dimensional (2D) aperture coding have been used for many years to break a similar trade-off. To provide a viable path to miniaturization for harsh environment field applications, we are investigating similar concepts in sector mass spectrometry. Recently, we demonstrated the viability of 1D aperture coding and here we provide a first investigation of 2D coding. In coded optical spectroscopy, 2D coding is preferred because of increased measurement diversity for improved conditioning and robustness of the result. To investigate its viability in mass spectrometry, analytes of argon, acetone, and ethanol were detected using a custom 90-degree magnetic sector mass spectrometer incorporating 2D coded apertures. We developed a mathematical forward model and reconstruction algorithm to successfully reconstruct the mass spectra from the 2D spatially coded ion positions. This 2D coding enabled a 3.5× throughput increase with minimal decrease in resolution. Several challenges were overcome in the mass spectrometer design to enable this coding, including the need for large uniform ion flux, a wide gap magnetic sector that maintains field uniformity, and a high resolution 2D detection system for ion imaging. Furthermore, micro-fabricated 2D coded apertures incorporating support structures were developed to provide a viable design that allowed ion transmission through the open elements of the code. PMID:25510933

  8. Characterisation of the volatile profiles of infant formulas by proton transfer reaction-mass spectrometry and gas chromatography-mass spectrometry

    NARCIS (Netherlands)

    Ruth, van S.M.; Floris, V.; Fayoux, S.

    2006-01-01

    The volatile profiles of 13 infant formulas were evaluated by proton transfer reaction-mass spectrometry (PTR-MS) and gas chromatography¿mass spectrometry (GC¿MS). The infant formulas varied in brand (Aptamil, Cow & Gate, SMA), type (for different infant target groups) and physical form (powder/

  9. Atmospheric-Pressure Chemical Ionization Tandem Mass Spectrometry (APGC/MS/MS) an Alternative to High-Resolution Mass Spectrometry (HRGC/HRMS) for the Determination of Dioxins

    NARCIS (Netherlands)

    Bavel, Van Bert; Geng, Dawei; Cherta, Laura; Nácher-Mestre, Jaime; Portolés, Tania; Ábalos, Manuela; Sauló, Jordi; Abad, Esteban; Dunstan, Jody; Jones, Rhys; Kotz, Alexander; Winterhalter, Helmut; Malisch, Rainer; Traag, Wim; Hagberg, Jessika; Ericson Jogsten, Ingrid; Beltran, Joaquim; Hernández, Félix

    2015-01-01

    The use of a new atmospheric-pressure chemical ionization source for gas chromatography (APGC) coupled with a tandem quadrupole mass spectrometry (MS/MS) system, as an alternative to high-resolution mass spectrometry (HRMS), for the determination of PCDDs/PCDFs is described. The potential of usin

  10. Identification of Fatty Acids, Phospholipids, and Their Oxidation Products Using Matrix-Assisted Laser Desorption Ionization Mass Spectrometry and Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Harmon, Christopher W.; Mang, Stephen A.; Greaves, John; Finlayson-Pitts, Barbara J.

    2010-01-01

    Electrospray ionization mass spectrometry (ESI-MS) and matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) have found increasing application in the analysis of biological samples. Using these techniques to solve problems in analytical chemistry should be an essential component of the training of undergraduate chemists. We…

  11. Secondary electrospray ionization ion mobility spectrometry/mass spectrometry of illicit drugs.

    Science.gov (United States)

    Wu, C; Siems, W F; Hill, H H

    2000-01-15

    A secondary electrospray ionization (SESI) method was developed as a nonradioactive ionization source for ion mobility spectrometry (IMS). This SESI method relied on the gas-phase interaction between charged particles created by electrospray ionization (ESI) and neutral gaseous sample molecules. Mass spectrometry (MS) was used as the detection method after ion mobility separation for ion identification. Preliminary investigations focussed on understanding the ionization process of SESI. The performance of ESI-IMS and SESI-IMS for illicit drug detection was evaluated by determining the analytical figures of merit. In general, SESI had a higher ionization efficiency for small volatile molecules compared with the electrospray method. The potential of developing a universal interface for both GC- and LC-MS with an addition stage of mobility separation was demonstrated.

  12. Uncovering biologically significant lipid isomers with liquid chromatography, ion mobility spectrometry and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Kyle, Jennifer E.; Zhang, Xing; Weitz, Karl K.; Monroe, Matthew E.; Ibrahim, Yehia M.; Moore, Ronald J.; Cha, Jeeyeon; Sun, Xiaofei; Lovelace, Erica S.; Wagoner, Jessica; Polyak, Stephen J.; Metz, Thomas O.; Dey, Sudhansu K.; Smith, Richard D.; Burnum-Johnson, Kristin E.; Baker, Erin S.

    2016-01-01

    Understanding how biological molecules are generated, metabolized and eliminated in living systems is important for interpreting processes such as immune response and disease pathology. While genomic and proteomic studies have provided vast amounts of information over the last several decades, interest in lipidomics has also grown due to improved analytical technologies revealing altered lipid metabolism in type 2 diabetes, cancer, and lipid storage disease. Liquid chromatography and mass spectrometry (LC-MS) measurements are currently the dominant approach for characterizing the lipidome by providing detailed information on the spatial and temporal composition of lipids. However, interpreting lipids’ biological roles is challenging due to the existence of numerous structural and stereoisomers (i.e. distinct acyl chain and double-bond positions), which are unresolvable using present LC-MS approaches. Here we show that combining structurally-based ion mobility spectrometry (IMS) with LC-MS measurements distinguishes lipid isomers and allows insight into biological and disease processes.

  13. Mass Spectrometry Based Lipidomics: An Overview of Technological Platforms

    Directory of Open Access Journals (Sweden)

    Harald C. Köfeler

    2012-01-01

    Full Text Available One decade after the genomic and the proteomic life science revolution, new ‘omics’ fields are emerging. The metabolome encompasses the entity of small molecules—Most often end products of a catalytic process regulated by genes and proteins—with the lipidome being its fat soluble subdivision. Within recent years, lipids are more and more regarded not only as energy storage compounds but also as interactive players in various cellular regulation cycles and thus attain rising interest in the bio-medical community. The field of lipidomics is, on one hand, fuelled by analytical technology advances, particularly mass spectrometry and chromatography, but on the other hand new biological questions also drive analytical technology developments. Compared to fairly standardized genomic or proteomic high-throughput protocols, the high degree of molecular heterogeneity adds a special analytical challenge to lipidomic analysis. In this review, we will take a closer look at various mass spectrometric platforms for lipidomic analysis. We will focus on the advantages and limitations of various experimental setups like ‘shotgun lipidomics’, liquid chromatography—Mass spectrometry (LC-MS and matrix assisted laser desorption ionization-time of flight (MALDI-TOF based approaches. We will also examine available software packages for data analysis, which nowadays is in fact the rate limiting step for most ‘omics’ workflows.

  14. Direct and Convenient Mass Spectrometry Sampling with Ambient Flame Ionization

    Science.gov (United States)

    Liu, Xiao-Pan; Wang, Hao-Yang; Zhang, Jun-Ting; Wu, Meng-Xi; Qi, Wan-Shu; Zhu, Hui; Guo, Yin-Long

    2015-11-01

    Recent innovations in ambient ionization technology for the direct analysis of various samples in their native environment facilitate the development and applications of mass spectrometry in natural science. Presented here is a novel, convenient and flame-based ambient ionization method for mass spectrometric analysis of organic compounds, termed as the ambient flame ionization (AFI) ion source. The key features of AFI ion source were no requirement of (high) voltages, laser beams and spray gases, but just using small size of n-butane flame (height approximately 1 cm, about 500 oC) to accomplish the rapid desorption and ionization for direct analysis of gaseous-, liquid- and solid-phase organic compounds, as well as real-world samples. This method has high sensitivity with a limit of detection of 1 picogram for propyphenazone, which allows consuming trace amount of samples. Compared to previous ionization methods, this ion source device is extremely simple, maintain-free, low-cost, user-friendly so that even an ordinary lighter (with n-butane as fuel) can achieve efficient ionization. A new orientation to mass spectrometry ion source exploitation might emerge from such a convenient, easy and inexpensive AFI ion source.

  15. Rapid analysis of trace pollutants using laser mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Organic pollution has been gaining more and more attention.Yet,at present the determination of virtually all of them,including polycyclic aromatic carbons (PAHs),the largest single class of chemical carcinogens known today,is made via pre-purification and pre-concentration.The major problems are complexity and time-consuming,thus,no ideal real-time on-line monitoring can be done.Laser mass spectrometry combines UV spectroscopy and time-of-flight mass spectrometry (TOF-MS) through resonance-enhanced multiphoton ionization (REMPI).It is characteristic of high sensitivity,high selectivity and rapidity.In this paper,after its principles,a small mobile laser mass spectrometer,in which a mini-excimer (KrF,248 nm) laser was used,is introduced.Real-time analysis of vehicle exhaust gas was made using this instrument,and the results showed some advantages over traditional methods:multicomponent detection,including benzene,toluene,xylene,C3-benzene,naphthalene,and methyl-naphthalene; high sensitivity (100 ppb);high time-resolution (0.1 s);and no need for pre-purification or pre-concentration of samples.

  16. Dehydrodimerization of pterostilbene during electrospray ionization mass spectrometry

    KAUST Repository

    Raji, Misjudeen

    2013-04-30

    RATIONALE Pterostilbene is a member of the hydroxystilbene family of compounds commonly found in plants such as blueberry and grapes. During the analysis of this compound by electrospray ionization mass spectrometry (ESI-MS), an ion was observed that corresponds to the dehydrodimer of pterostilbene in mass-to-charge ratio. Since such unexpected dimerization may lead to decreased monomer signal during quantitative analysis, it was of interest to identify the origin and structure of the observed pterostilbene dimer and examine the experimental conditions that influence its formation. METHODS Liquid Chromatography/Mass Spectrometry (LC/MS), Nuclear Magnetic Resonance (NMR), and High-Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) were used to examine the origin of the dimerization products. The structure of the formed pterostilbene dimer was examined by performing MSn analysis on the dimer ion. Effects of solvent composition, analyte concentration, radical scavenger, and other experimental conditions on the dimerization were also studied. RESULTS LC/MS and NMR analyses clearly showed that the starting solution did not contain the pterostilbene dimer. Solvent type and radical scavenger concentration were found to have pronounced effects on the dimer formation. Particularly, presence of acetonitrile or ammonium acetate had favorable effects on the extent of dimerization during ESI-MS analysis whereas hydroquinone and butylated hydroquinone had negative effects. Dimer formation decreased at high flow rates and when fused-silica capillary was used as the spray needle. CONCLUSIONS The data indicate that this dimerization occurs as a result of solution-phase electrochemical reactions taking place during the electrospray process. A possible structure for this dimer was proposed based on the MSn analysis and was similar to that of the enzymatically derived pterostilbene dehydrodimer already reported in the literature. Copyright © 2013 John Wiley & Sons, Ltd

  17. Diesel characterization by high-resolution mass spectrometry - gas chromatography

    International Nuclear Information System (INIS)

    High-resolution mass spectrometry-gas chromatography is combined with the HC22 method in order to obtain detailed information about the chemical composition of diesel and the distribution of different compound types in terms of its final boiling temperature from a single analysis. The total time elapsed from sample injection and signal processing to obtain final results is 90 minutes. This fact makes this methodology a new and very important tool for the decision making process concerning the most suitable final boiling temperature and the type of treatment of the product in order to obtain diesel that fulfills the international standards. The consistency and repeatability of the experimental results are demonstrated

  18. Vaporization Studies of Olivine via Knudsen Effusion Mass Spectrometry

    Science.gov (United States)

    Costa, G. C. C.; Jacobson, N. S.

    2014-01-01

    Olivine is the major mineral in the Earth's upper mantle occurring predominantly in igneous rocks and has been identified in meteorites, asteroids, the Moon and Mars. Among many other important applications in planetary and materials sciences, the thermodynamic properties of vapor species from olivine are crucial as input parameters in computational modelling of the atmospheres of hot, rocky exoplanets (lava planets). There are several weight loss studies of olivine vaporization in the literature and one Knudsen Effusion Mass Spectrometry (KEMS) study. In this study, we examine a forsterite-rich olivine (93% forsterite and 7% fayalite, Fo93Fa7) with KEMS to further understand its vaporization and thermodynamic properties.

  19. Biomedical mass spectrometry in today's and tomorrow's clinical microbiology laboratories.

    Science.gov (United States)

    van Belkum, Alex; Welker, Martin; Erhard, Marcel; Chatellier, Sonia

    2012-05-01

    Clinical microbiology is a conservative laboratory exercise where base technologies introduced in the 19th century remained essentially unaltered. High-tech mass spectrometry (MS) has changed that. Within a few years following its adaptation to microbiological diagnostics, MS has been introduced, embraced, and broadly accepted by clinical microbiology laboratories throughout the world as an innovative tool for definitive bacterial species identification. Herein, we review the current state of the art with respect to this exciting new technology and discuss potential future applications. PMID:22357505

  20. Web Resources for Mass Spectrometry-based Proteomics

    Institute of Scientific and Technical Information of China (English)

    Tao Chen; Jie Zhao; Jie Ma; Yunping Zhu

    2015-01-01

    With the development of high-resolution and high-throughput mass spectrometry (MS) technology, a large quantum of proteomic data is continually being generated. Collecting and shar-ing these data are a challenge that requires immense and sustained human effort. In this report, we provide a classification of important web resources for MS-based proteomics and present rating of these web resources, based on whether raw data are stored, whether data submission is supported, and whether data analysis pipelines are provided. These web resources are important for biologists involved in proteomics research.

  1. Monitoring of wine aging process by electrospray ionization mass spectrometry

    Directory of Open Access Journals (Sweden)

    Alexandra Christine Helena Frankland Sawaya

    2011-09-01

    Full Text Available The characterization of wine samples by direct insertion electrospray ionization mass spectrometry (ESI-MS, without pre-treatment or chromatographic separation, in a process denominated fingerprinting, has been applied to several samples of wine produced with grapes of the Pinot noir, Merlot and Cabernet Sauvignon varieties from the state o Rio Grande do Sul, in Brazil. The ESI-MS fingerprints of the samples detected changes which occurred during the aging process in the three grape varieties. Principal Component Analysis (PCA of the negative ion mode fingerprints was used to group the samples, pinpoint the main changes in their composition, and indicate marker ions for each group of samples.

  2. Application of accelerator mass spectrometry in aluminum metabolism studies

    International Nuclear Information System (INIS)

    The recent recognition that aluminum causes toxicity in uremic patients and may be associated with Alzheimer's disease has stimulated many studies of its biochemical effects. However, such studies were hampered by the lack of a suitable tracer. In a novel experiment, we have applied the new technique of accelerator mass spectrometry to investigate aluminum kinetics in rats, using as a marker the long-lived isotope 26Al. We present the first aluminum kinetic model for a biological system. The results clearly demonstrate the advantage this technique holds for isotope tracer studies in animals as well as humans. (Author) (24 refs., 3 figs.)

  3. Identification of Associated Proteins by Immunoprecipitation and Mass Spectrometry Analysis.

    Science.gov (United States)

    Cao, Xiumei; Yan, Jianshe

    2016-01-01

    Protein-protein interactions play central roles in intercellular and intracellular signal transduction. Impairment of protein-protein interactions causes many diseases such as cancer, cardiomyopathies, diabetes, microbial infections, and genetic and neurodegenerative disorders. Immunoprecipitation is a technique in which a target protein of interest bound by an antibody is used to pull down the protein complex out of cell lysates, which can be identified by mass spectrometry. Here, we describe the protocol to immunoprecipitate and identify the components of the protein complexes of ElmoE in Dictyostelium discoideum cells. PMID:27271899

  4. Triplex and quadruplex DNA structures studied by electrospray mass spectrometry

    OpenAIRE

    Rosu, Frédéric; Gabelica, Valérie; Houssier, Claude; Colson, Pierre; De Pauw, Edwin

    2002-01-01

    DNA triplex and quadruplex structures have been successfully detected by electrospray ionization mass spectrometry (ESI-MS). Circular dichroism and UV-melting experiments show that these structures are stable in 150 mM ammonium acetate at pH 7 for the quadruplexes and pH 5.5 for the triplexes. The studied quadruplexes were the tetramer [d(TGGGGT)](4), the dimer [d(GGGGTTTTGGGG)](2), and the intramolecular folded strand dGGG(TTAGGG)(3), which is an analog of the human telomeric sequence. The a...

  5. Incorporating Biological Mass Spectrometry into Undergraduate Teaching Labs, Part 1: Identifying Proteins Based on Molecular Mass

    Science.gov (United States)

    Arnquist, Isaac J.; Beussman, Douglas J.

    2007-01-01

    Biological mass spectrometry is an important analytical technique in drug discovery, proteomics, and research at the biology-chemistry interface. Currently, few hands-on opportunities exist for undergraduate students to learn about this technique. With the 2002 Nobel Prize being awarded, in part, for the development of biological mass…

  6. Tandem mass spectrometry data quality assessment by self-convolution

    Directory of Open Access Journals (Sweden)

    Tham Wai

    2007-09-01

    Full Text Available Abstract Background Many algorithms have been developed for deciphering the tandem mass spectrometry (MS data sets. They can be essentially clustered into two classes. The first performs searches on theoretical mass spectrum database, while the second based itself on de novo sequencing from raw mass spectrometry data. It was noted that the quality of mass spectra affects significantly the protein identification processes in both instances. This prompted the authors to explore ways to measure the quality of MS data sets before subjecting them to the protein identification algorithms, thus allowing for more meaningful searches and increased confidence level of proteins identified. Results The proposed method measures the qualities of MS data sets based on the symmetric property of b- and y-ion peaks present in a MS spectrum. Self-convolution on MS data and its time-reversal copy was employed. Due to the symmetric nature of b-ions and y-ions peaks, the self-convolution result of a good spectrum would produce a highest mid point intensity peak. To reduce processing time, self-convolution was achieved using Fast Fourier Transform and its inverse transform, followed by the removal of the "DC" (Direct Current component and the normalisation of the data set. The quality score was defined as the ratio of the intensity at the mid point to the remaining peaks of the convolution result. The method was validated using both theoretical mass spectra, with various permutations, and several real MS data sets. The results were encouraging, revealing a high percentage of positive prediction rates for spectra with good quality scores. Conclusion We have demonstrated in this work a method for determining the quality of tandem MS data set. By pre-determining the quality of tandem MS data before subjecting them to protein identification algorithms, spurious protein predictions due to poor tandem MS data are avoided, giving scientists greater confidence in the

  7. Distance-of-Flight Mass Spectrometry: What, Why, and How?

    Science.gov (United States)

    Dennis, Elise A.; Gundlach-Graham, Alexander W.; Ray, Steven J.; Enke, Christie G.; Hieftje, Gary M.

    2016-11-01

    Distance-of-flight mass spectrometry (DOFMS) separates ions of different mass-to-charge ( m/ z) by the distance they travel in a given time after acceleration. Like time-of-flight mass spectrometry (TOFMS), separation and mass assignment are based on ion velocity. However, DOFMS is not a variant of TOFMS; different methods of ion focusing and detection are used. In DOFMS, ions are driven orthogonally, at the detection time, onto an array of detectors parallel to the flight path. Through the independent detection of each m/ z, DOFMS can provide both wider dynamic range and increased throughput for m/ z of interest compared with conventional TOFMS. The iso-mass focusing and detection of ions is achieved by constant-momentum acceleration (CMA) and a linear-field ion mirror. Improved energy focus (including turn-around) is achieved in DOFMS, but the initial spatial dispersion of ions remains unchanged upon detection. Therefore, the point-source nature of surface ionization techniques could put them at an advantage for DOFMS. To date, three types of position-sensitive detectors have been used for DOFMS: a microchannel plate with a phosphorescent screen, a focal plane camera, and an IonCCD array; advances in detector technology will likely improve DOFMS figures-of-merit. In addition, the combination of CMA with TOF detection has provided improved resolution and duty factor over a narrow m/ z range (compared with conventional, single-pass TOFMS). The unique characteristics of DOFMS can enable the intact collection of large biomolecules, clusters, and organisms. DOFMS might also play a key role in achieving the long-sought goal of simultaneous MS/MS.

  8. Distance-of-Flight Mass Spectrometry: What, Why, and How?

    Science.gov (United States)

    Dennis, Elise A.; Gundlach-Graham, Alexander W.; Ray, Steven J.; Enke, Christie G.; Hieftje, Gary M.

    2016-08-01

    Distance-of-flight mass spectrometry (DOFMS) separates ions of different mass-to-charge (m/z) by the distance they travel in a given time after acceleration. Like time-of-flight mass spectrometry (TOFMS), separation and mass assignment are based on ion velocity. However, DOFMS is not a variant of TOFMS; different methods of ion focusing and detection are used. In DOFMS, ions are driven orthogonally, at the detection time, onto an array of detectors parallel to the flight path. Through the independent detection of each m/z, DOFMS can provide both wider dynamic range and increased throughput for m/z of interest compared with conventional TOFMS. The iso-mass focusing and detection of ions is achieved by constant-momentum acceleration (CMA) and a linear-field ion mirror. Improved energy focus (including turn-around) is achieved in DOFMS, but the initial spatial dispersion of ions remains unchanged upon detection. Therefore, the point-source nature of surface ionization techniques could put them at an advantage for DOFMS. To date, three types of position-sensitive detectors have been used for DOFMS: a microchannel plate with a phosphorescent screen, a focal plane camera, and an IonCCD array; advances in detector technology will likely improve DOFMS figures-of-merit. In addition, the combination of CMA with TOF detection has provided improved resolution and duty factor over a narrow m/z range (compared with conventional, single-pass TOFMS). The unique characteristics of DOFMS can enable the intact collection of large biomolecules, clusters, and organisms. DOFMS might also play a key role in achieving the long-sought goal of simultaneous MS/MS.

  9. An explicit study of aerosol mass conversion and its parameterization in warm rain formation of cumulus clouds

    Directory of Open Access Journals (Sweden)

    J. Sun

    2013-10-01

    Full Text Available The life time of atmospheric aerosols is highly affected by in-cloud scavenging processes. Aerosol mass conversion from aerosols embedded in cloud droplets into aerosols embedded in raindrops is a pivotal pathway for wet removal of aerosols in clouds. The aerosol mass conversion rate in the bulk microphysics parameterizations is always assumed to be linearly related to the precipitation production rate, which includes the cloud water autoconversion rate and the cloud water accretion rate. The ratio of the aerosol mass concentration conversion rate to the cloud aerosol mass concentration has typically been considered to be the same as the ratio of the precipitation production rate to the cloud droplet mass concentration. However, the mass of an aerosol embedded in a cloud droplet is not linearly proportional to the mass of the cloud droplet. A simple linear relationship cannot be drawn between the precipitation production rate and the aerosol mass concentration conversion rate. In this paper, we studied the evolution of aerosol mass concentration conversion rates in a warm rain formation process with a 1.5-dimensional non-hydrostatic convective cloud and aerosol interaction model in the bin microphysics. We found that the ratio of the aerosol mass conversion rate to the cloud aerosol mass concentration can be statistically expressed by the ratio of the precipitation production rate to the cloud droplet mass concentration with an exponential function. We further gave some regression equations to determine aerosol conversions in the warm rain formation under different threshold radii of raindrops and different aerosol size distributions.

  10. MassNet: a functional annotation service for protein mass spectrometry data

    OpenAIRE

    Park, Daeui; Kim, Byoung-Chul; Cho, Seong-Woong; Park, Seong-Jin; Choi, Jong-Soon; Kim, Seung Il; Bhak, Jong; Lee, Sunghoon

    2008-01-01

    Although mass spectrometry has been frequently used to identify proteins, there are no web servers that provide comprehensive functional annotation of those identified proteins. It is necessary to provide such web service due to a rapid increase in the data. We, therefore, introduce MassNet, which provides (i) physico-chemical analysis information, (ii) KEGG pathway assignment (iii) Gene Ontology mapping and (iv) protein–protein interaction (PPI) prediction for the data from MASCOT, Prospecto...

  11. Accessing natural product biosynthetic processes by mass spectrometry.

    Science.gov (United States)

    Bumpus, Stefanie B; Kelleher, Neil L

    2008-10-01

    Two important classes of natural products are made by nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs). With most biosynthetic intermediates covalently tethered during biogenesis, protein mass spectrometry (MS) has proven invaluable for their interrogation. New mass spectrometric assay formats (such as selective cofactor ejection and proteomics style LC-MS) are showcased here in the context of functional insights into new breeds of NRPS/PKS enzymes, including the first characterization of an 'iterative' PKS, the biosynthesis of the enediyne antitumor antibiotics, the study of a new strategy for PKS initiation via a GNAT-like mechanism, and the analysis of branching strategies in the so-called 'AT-less' NRPS/PKS hybrid systems. The future of MS analysis of NRPS and PKS biosynthetic pathways lies in adoption and development of methods that continue bridging enzymology with proteomics as both fields continue their post-genomic acceleration. PMID:18706516

  12. Testing and Validation of Computational Methods for Mass Spectrometry.

    Science.gov (United States)

    Gatto, Laurent; Hansen, Kasper D; Hoopmann, Michael R; Hermjakob, Henning; Kohlbacher, Oliver; Beyer, Andreas

    2016-03-01

    High-throughput methods based on mass spectrometry (proteomics, metabolomics, lipidomics, etc.) produce a wealth of data that cannot be analyzed without computational methods. The impact of the choice of method on the overall result of a biological study is often underappreciated, but different methods can result in very different biological findings. It is thus essential to evaluate and compare the correctness and relative performance of computational methods. The volume of the data as well as the complexity of the algorithms render unbiased comparisons challenging. This paper discusses some problems and challenges in testing and validation of computational methods. We discuss the different types of data (simulated and experimental validation data) as well as different metrics to compare methods. We also introduce a new public repository for mass spectrometric reference data sets ( http://compms.org/RefData ) that contains a collection of publicly available data sets for performance evaluation for a wide range of different methods. PMID:26549429

  13. Deblurring molecular images using desorption electrospray ionization mass spectrometry

    Science.gov (United States)

    Parry, R. Mitchell; Galhena, Asiri S.; Fernandez, Facundo M.; Wang, May D.

    2016-01-01

    Traditional imaging techniques for studying the spatial distribution of biological molecules such as proteins, metabolites, and lipids, require the a priori selection of a handful of target molecules. Imaging mass spectrometry provides a means to analyze thousands of molecules at a time within a tissue sample, adding spatial detail to proteomic, metabolomic, and lipidomic studies. Compared to traditional microscopic images, mass spectrometric images have reduced spatial resolution and require a destructive acquisition process. In order to increase spatial detail, we propose a constrained acquisition path and signal degradation model enabling the use of a general image deblurring algorithm. Our analysis shows the potential of this approach and supports prior observations that the effect of the sprayer focuses on a central region much smaller than the extent of the spray. PMID:19963935

  14. Statistical design of quantitative mass spectrometry-based proteomic experiments.

    Science.gov (United States)

    Oberg, Ann L; Vitek, Olga

    2009-05-01

    We review the fundamental principles of statistical experimental design, and their application to quantitative mass spectrometry-based proteomics. We focus on class comparison using Analysis of Variance (ANOVA), and discuss how randomization, replication and blocking help avoid systematic biases due to the experimental procedure, and help optimize our ability to detect true quantitative changes between groups. We also discuss the issues of pooling multiple biological specimens for a single mass analysis, and calculation of the number of replicates in a future study. When applicable, we emphasize the parallels between designing quantitative proteomic experiments and experiments with gene expression microarrays, and give examples from that area of research. We illustrate the discussion using theoretical considerations, and using real-data examples of profiling of disease.

  15. Origin of the chemical noise in ambient mass spectrometry

    International Nuclear Information System (INIS)

    The instrumental background of ambient mass spectrometry, (API-MS) is analyzed and the possible potential origins of the background noise is identified. According to the mass spectra obtained using the API-MS instruments by different manufacturers, the characteristic fragment ions all indicated that the background noise are resulted from the phthalates such as diethyl phthalate (DEP), dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), bis (2-ethylhexyl) phthalate (DEHP), and silicones such as decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6). These chemicals are probably released from the polymeric materials used in the ionization sources, such as O-type sealing ring etc. In addition, the instrumental background has to be considered especially during the analysis of phthalate and peptide compounds. (authors)

  16. Mass spectrometry. [in organic ion and biorganic chemistry and medicine

    Science.gov (United States)

    Burlingame, A. L.; Cox, R. E.; Derrick, P. J.

    1974-01-01

    Review of the present status of mass spectrometry in the light of pertinent recent publications spanning the period from December 1971 to January 1974. Following an initial survey of techniques, instruments, and computer applications, a sharp distinction is made between the chemistry of organic (radical-)ions and analytical applications in biorganic chemistry and medicine. The emphasis is on the chemistry of organic (radical-)ions at the expense of inorganic, organometallic, and surface ion chemistry. Biochemistry and medicine are chosen because of their contemporary importance and because of the stupendous contributions of mass spectroscopy to these fields in the past two years. In the review of gas-phase organic ion chemistry, special attention is given to studies making significant contributions to the understanding of ion chemistry.

  17. Laser resonant-ionization mass spectrometry of actinides

    International Nuclear Information System (INIS)

    Laser resonant-ionization mass spectrometry has been used to determine small amounts of actinides. The high sensitivity and selectivity of this method has been achieved by three-step photoionization of actinide atoms followed by time-of-flight measurement. The laser system for photoionization consists of a pulsed copper vapour laser of 30 W average power at a pulse repetition rate of 6.5 kHz which is coupled to three dye lasers. The time-of-flight spectrometer has a mass resolution of about 2500. Resonance signals with count rates of several kilohertz were obtained with actinide samples of 1010-1012 atoms yielding a detection limit of 108 atoms in the sample. With some improvements a detection sensitivity of about 106 atoms of plutonium, americium and curium should be reached. (orig.)

  18. Characteristics of tyre dust in polluted air: Studies by single particle mass spectrometry (ATOFMS)

    Science.gov (United States)

    Dall'Osto, Manuel; Beddows, David C. S.; Gietl, Johanna K.; Olatunbosun, Oluremi A.; Yang, Xiaoguang; Harrison, Roy M.

    2014-09-01

    There is a paucity of quantitative knowledge on the contributions of non-exhaust (abrasion and re-suspension) sources to traffic emissions. Abrasive emissions can be broadly categorised as tyre wear, brake wear and road dust/road surface wear. Current research often considers road dust and tyre dust as externally mixed particles, the former mainly composed of mineral matter and the latter solely composed of mainly organic matter and some trace elements. The aim of this work was to characterise tyre wear from both laboratory and field studies by using Aerosol Time-Of-Flight Mass Spectrometry (ATOFMS). Real-time single particle chemical composition was obtained from a set of rubber tyres rotating on a metal surface. Bimodal particle number size distributions peaking at 35 nm and 85 nm were obtained from SMPS/APS measurements over the range 6-20,000 nm. ATOFMS mass spectra of tyre wear in the particle size range 200-3000 nm diameter show peaks due to exo-sulphur compounds, nitrate, Zn and ions of high molecular weight (m/z > 100) attributed to organic polymers. Two large ATOFMS datasets collected from a number of outdoor studies were examined. The former was constituted of 48 road dust samples collected on the roads of London. The latter consisted of ATOFMS ambient air field studies from Europe, overall composed of more than 2,000,000 single particle mass spectra. The majority (95%) of tyre wear particles present in the road dust samples and atmospheric samples are internally mixed with metals (Li, Na, Ca, Fe, Ti), as well as phosphate. It is concluded that the interaction of tyres with the road surface creates particles internally mixed from two sources: tyre rubber and road surface materials. Measurements of the tyre rubber component alone may underestimate the contribution of tyre wear to concentrations of airborne particulate matter. The results presented are especially relevant for urban aerosol source apportionment and PM2.5 exposure assessment.

  19. High Resolution Mass Spectrometry of Polyfluorinated Polyether-Based Formulation

    Science.gov (United States)

    Dimzon, Ian Ken; Trier, Xenia; Frömel, Tobias; Helmus, Rick; Knepper, Thomas P.; de Voogt, Pim

    2016-02-01

    High resolution mass spectrometry (HRMS) was successfully applied to elucidate the structure of a polyfluorinated polyether (PFPE)-based formulation. The mass spectrum generated from direct injection into the MS was examined by identifying the different repeating units manually and with the aid of an instrument data processor. Highly accurate mass spectral data enabled the calculation of higher-order mass defects. The different plots of MW and the nth-order mass defects (up to n = 3) could aid in assessing the structure of the different repeating units and estimating their absolute and relative number per molecule. The three major repeating units were -C2H4O-, -C2F4O-, and -CF2O-. Tandem MS was used to identify the end groups that appeared to be phosphates, as well as the possible distribution of the repeating units. Reversed-phase HPLC separated of the polymer molecules on the basis of number of nonpolar repeating units. The elucidated structure resembles the structure in the published manufacturer technical data. This analytical approach to the characterization of a PFPE-based formulation can serve as a guide in analyzing not just other PFPE-based formulations but also other fluorinated and non-fluorinated polymers. The information from MS is essential in studying the physico-chemical properties of PFPEs and can help in assessing the risks they pose to the environment and to human health.

  20. Mass Spectrometry of Atmospheric Pressure Surface Wave Discharges

    Science.gov (United States)

    Ridenti, M. A.; Souza-Corrêa, J. A.; Amorim, J.

    2016-05-01

    By applying mass spectrometry techniques, we carried out measurements of ionic mass spectrum and their energy distribution in order to investigate an atmospheric argon discharge by using a surfatron surface-wave device. The mass and energy distribution measurements were performed with fixed flow rate (2.5 SLM) of pure argon gas (99.999%) and different Ar-O2 gas mixture compositions (99-1, 98-2 and 97-3). The mass spectra and energy distributions were recorded for Ar+, O+, O+ 2, N+ and N2 +. The axial distribution profiles of ionic mass and their energy were obtained for different experimental conditions as a function of the plasma length. The results showed that the peak of the positive ion energy distributions shifted to higher energies and also that the distribution width increased as the distance between the sampling orifice and the launcher gap was increased. It was also found that under certain experimental conditions the ion flux of atomic species were higher than the ion flux of their diatomic counterpart. The motivation of this study was to obtain a better understanding of a surface wave discharge in atmospheric pressure that may play a key role on new second generation biofuel technologies.

  1. An ion-to-photon conversion detector for mass spectrometry

    Science.gov (United States)

    Dubois, F.; Knochenmuss, R.; Zenobi, R.

    1997-12-01

    An ion-to-photon conversion detector (IPD) for time-of-flight mass spectrometry was studied and tested with ions produced by matrix-assisted laser desorption-ionization. The detector consisted of a conversion surface located at the end of the drift tube of a time-of-flight mass spectrometer and, behind it, a head-on photomultiplier tube. Fluorescent organic scintillator materials like Bu-PBD [2-(4-t-buthylphenyl)-5-(4-biphenylyl)-1,3,4-oxidiazole] were found to be the most efficient converters of those materials tested. Similar mass resolutions were found with the ion-to-photo detector and standard microchannel plates in a linear time-of-flight instrument. The background noise of the IPD was more intense than with microchannel plates. Slow unfocused ions are suspected to contribute to this noise. Test analytes as large as 70 000 Da could be measured with the IPD. Even with no secondary particle conversion surface in front of the IPD, masses up to approximately 20 000 Da may be more efficiently detected with the IPD than the MCP. For higher masses, a conversion dynode should be considered for increased signal.

  2. Bead Separation and MALDI-TOF Mass Spectrometry Analysis

    Directory of Open Access Journals (Sweden)

    Nai-Jun Fan

    2012-01-01

    Full Text Available Background. Colorectal cancer (CRC is one of the most common cancers in the world, identification of biomarkers for early detection of CRC represents a relevant target. The present study aims to determine serum peptidome patterns for CRC diagnosis. Methods. The present work focused on serum proteomic analysis of 32 health volunteers and 38 CRC by ClinProt Kit combined with mass spectrometry. This approach allowed the construction of a peptide patterns able to differentiate the studied populations. An independent group of serum (including 33 health volunteers, 34 CRC, 16 colorectal adenoma, 36 esophageal carcinoma, and 31 gastric carcinoma samples was used to verify the diagnostic and differential diagnostic capability of the peptidome patterns blindly. An immunoassay method was used to determine serum CEA of CRC and controls. Results. A quick classifier algorithm was used to construct the peptidome patterns for identification of CRC from controls. Two of the identified peaks at m/z 741 and 7772 were used to construct peptidome patterns, achieving an accuracy close to 100% (>CEA, P<0.05. Furthermore, the peptidome patterns could differentiate validation group with high accuracy. Conclusions. These results suggest that the ClinProt Kit combined with mass spectrometry yields significantly higher accuracy for the diagnosis and differential diagnosis of CRC.

  3. Rapid Detection of Irreversible Acetylcholineasterase Inhibitor by Mass Spectrometry Assay

    Institute of Scientific and Technical Information of China (English)

    蔡婷婷; 张立; 汪蓉; 梁晨; 赵武生; 傅得锋; 张玉荣; 郭寅龙

    2012-01-01

    Here we developed a rapid method to detect acetylcholinesterase (ACHE) activity by matrix-assisted laser de- sorption/ionization Fourier transform mass spectrometry (MALDI-FTMS) for screening irreversible AChE inhibi- tors. Due to its good salt-tolerance and low sample consumption, MALDI-FTMS could facilitate rapid detection, especially detection in real application. AChE activity was determined through calculating abundance of substrate and product in mass spectrometry. By this approach, we investigated the relation of organophosphorous (OP) con- centrations and AChE inhibition. Shown in different inhibition curves from different OP pesticides, enzyme inhibi- tions still kept good correlation with concentration of OPs. Finally, this AChE-inhibited method was applied to screen whole bloods of four decedents and discuss their death reason. In contrast to healthy persons, three of dece- dents showed low AChE activity, and probably died for irreversible AChE inhibitors. Through the following de- tecting in GC-MS/MS, the possible death reason of these three decedents was confirmed, and another decedent actually died for sumicidin, a non-AChE inhibitor. It demonstrated that screening irreversible AChE inhibitors by detecting enzyme activity in MALDI-FTMS provided fast and accurate analysis results and excluded another toxicants not functioning on ACHE. This method offered alternative choices for indicating the existence of enzyme inhibitors.

  4. Mass Spectrometry Coupled Experiments and Protein Structure Modeling Methods

    Directory of Open Access Journals (Sweden)

    Lee Sael

    2013-10-01

    Full Text Available With the accumulation of next generation sequencing data, there is increasing interest in the study of intra-species difference in molecular biology, especially in relation to disease analysis. Furthermore, the dynamics of the protein is being identified as a critical factor in its function. Although accuracy of protein structure prediction methods is high, provided there are structural templates, most methods are still insensitive to amino-acid differences at critical points that may change the overall structure. Also, predicted structures are inherently static and do not provide information about structural change over time. It is challenging to address the sensitivity and the dynamics by computational structure predictions alone. However, with the fast development of diverse mass spectrometry coupled experiments, low-resolution but fast and sensitive structural information can be obtained. This information can then be integrated into the structure prediction process to further improve the sensitivity and address the dynamics of the protein structures. For this purpose, this article focuses on reviewing two aspects: the types of mass spectrometry coupled experiments and structural data that are obtainable through those experiments; and the structure prediction methods that can utilize these data as constraints. Also, short review of current efforts in integrating experimental data in the structural modeling is provided.

  5. Multiphoton ionization mass spectrometry of nitrated polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Tang, Yuanyuan; Imasaka, Tomoko; Yamamoto, Shigekazu; Imasaka, Totaro

    2015-08-01

    In order to suppress the fragmentation and improve the sensitivity for determination of nitrated polycyclic aromatic hydrocarbons (NPAHs), the mechanism of multiphoton ionization was studied for the following representative NPAHs, 9-nitroanthracene, 3-nitrofluoranthene, and 1-nitropyrene. The analytes were extracted from the PM2.5 on the sampling filter ultrasonically, and were measured using gas chromatography/multiphoton ionization/time-of-flight mass spectrometry with a femtosecond tunable laser in the range from 267 to 405 nm. As a result, a molecular ion was observed as the major ion and fragmentation was suppressed at wavelengths longer than 345 nm. Furthermore, the detection limit measured at 345 nm was measured to be the subpicogram level. The organic compounds were extracted from a 2.19 mg sample of particulate matter 2.5 (PM2.5), and the extract was subjected to multiphoton ionization mass spectrometry after gas chromatograph separation. The background signals were drastically suppressed at 345 nm, and the target NPAHs, including 9-nitroanthracene and 1-nitropyrene, were detected, and their concentrations were determined to be 5 and 3 pg/m(3), respectively. PMID:26048831

  6. Extractive electrospray ionization mass spectrometry for uranium chemistry studies.

    Science.gov (United States)

    Chen, Huanwen; Luo, Mingbiao; Xiao, Saijin; Ouyang, Yongzhong; Zhou, Yafei; Zhang, Xinglei

    2013-01-01

    Uranium chemistry is of sustainable interest. Breakthroughs in uranium studies make serious impacts in many fields including chemistry, physics, energy and biology, because uranium plays fundamentally important roles in these fields. Substantial progress in uranium studies normally requires development of novel analytical tools. Extractive electrospray ionization mass spectrometry (EESI-MS) is a sensitive technique for trace detection of various analytes in complex matrices without sample pretreatment. EESI-MS shows excellent performance for monitoring uranium species in various samples at trace levels since it tolerates extremely complex matrices. Therefore, EESI-MS is an alternative choice for studying uranium chemistry, especially when it combines ion trap mass spectrometry. In this presentation, three examples of EESI-MS for uranium chemistry studies will be given, illustrating the potential applications of EESI-MS in synthesis chemistry, physical chemistry, and analytical chemistry of uranium. More specifically, case studies on EESI-MS for synthesis and characterization of novel uranium species, and for rapid detection of uranium and its isotope ratios in various samples will be presented. Novel methods based on EESI-MS for screening uranium ores and radioactive iodine-129 will be presented. PMID:24349940

  7. Optimal selection of epitopes for TXP-immunoaffinity mass spectrometry

    Directory of Open Access Journals (Sweden)

    Joos Thomas

    2010-06-01

    Full Text Available Abstract Background Mass spectrometry (MS based protein profiling has become one of the key technologies in biomedical research and biomarker discovery. One bottleneck in MS-based protein analysis is sample preparation and an efficient fractionation step to reduce the complexity of the biological samples, which are too complex to be analyzed directly with MS. Sample preparation strategies that reduce the complexity of tryptic digests by using immunoaffinity based methods have shown to lead to a substantial increase in throughput and sensitivity in the proteomic mass spectrometry approach. The limitation of using such immunoaffinity-based approaches is the availability of the appropriate peptide specific capture antibodies. Recent developments in these approaches, where subsets of peptides with short identical terminal sequences can be enriched using antibodies directed against short terminal epitopes, promise a significant gain in efficiency. Results We show that the minimal set of terminal epitopes for the coverage of a target protein list can be found by the formulation as a set cover problem, preceded by a filtering pipeline for the exclusion of peptides and target epitopes with undesirable properties. Conclusions For small datasets (a few hundred proteins it is possible to solve the problem to optimality with moderate computational effort using commercial or free solvers. Larger datasets, like full proteomes require the use of heuristics.

  8. Analysis of hazardous biological material by MALDI mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    KL Wahl; KH Jarman; NB Valentine; MT Kingsley; CE Petersen; ST Cebula; AJ Saenz

    2000-03-21

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-MS) has become a valuable tool for analyzing microorganisms. The speed with which data can be obtained from MALDI-MS makes this a potentially important tool for biological health hazard monitoring and forensic applications. The excitement in the mass spectrometry community in this potential field of application is evident by the expanding list of research laboratories pursuing development of MALDI-MS for bacterial identification. Numerous research groups have demonstrated the ability to obtain unique MALDI-MS spectra from intact bacterial cells and bacterial cell extracts. The ability to differentiate strains of the same species has been investigated. Reproducibility of MALDI-MS spectra from bacterial species under carefully controlled experimental conditions has also been demonstrated. Wang et al. have reported on interlaboratory reproducibility of the MALDI-MS analysis of several bacterial species. However, there are still issues that need to be addressed, including the careful control of experimental parameters for reproducible spectra and selection of optimal experimental parameters such as solvent and matrix.

  9. Expanded newborn screening by mass spectrometry: New tests, future perspectives.

    Science.gov (United States)

    Ombrone, Daniela; Giocaliere, Elisa; Forni, Giulia; Malvagia, Sabrina; la Marca, Giancarlo

    2016-01-01

    Tandem mass spectrometry (MS/MS) has become a leading technology used in clinical chemistry and has shown to be particularly sensitive and specific when used in newborn screening (NBS) tests. The success of tandem mass spectrometry is due to important advances in hardware, software and clinical applications during the last 25 years. MS/MS permits a very rapid measurement of many metabolites in different biological specimens by using filter paper spots or directly on biological fluids. Its use in NBS give us the chance to identify possible treatable metabolic disorders even when asymptomatic and the benefits gained by this type of screening is now recognized worldwide. Today the use of MS/MS for second-tier tests and confirmatory testing is promising especially in the early detection of new disorders such as some lysosomal storage disorders, ADA and PNP SCIDs, X-adrenoleucodistrophy (X-ALD), Wilson disease, guanidinoacetate methyltransferase deficiency (GAMT), and Duchenne muscular dystrophy. The new challenge for the future will be reducing the false positive rate by using second-tier tests, avoiding false negative results by using new specific biomarkers and introducing new treatable disorders in NBS programs.

  10. Data-Independent Microbial Metabolomics with Ambient Ionization Mass Spectrometry

    Science.gov (United States)

    Rath, Christopher M.; Yang, Jane Y.; Alexandrov, Theodore; Dorrestein, Pieter C.

    2013-08-01

    Atmospheric ionization methods are ideally suited for prolonged MS/MS analysis. Data-independent MS/MS is a complementary technique for analysis of biological samples as compared to data-dependent analysis. Here, we pair data-independent MS/MS with the ambient ionization method nanospray desorption electrospray ionization (nanoDESI) for untargeted analysis of bacterial metabolites. Proof-of-principle data and analysis are illustrated by sampling Bacillus subtilis and Pseudomonas aeruginosa directly from Petri dishes. We found that this technique enables facile comparisons between strains via MS and MS/MS plots which can be translated to chemically informative molecular maps through MS/MS networking. The development of novel techniques to characterize microbial metabolites allows rapid and efficient analysis of metabolic exchange factors. This is motivated by our desire to develop novel techniques to explore the role of interspecies interactions in the environment, health, and disease. This is a contribution to honor Professor Catherine C. Fenselau in receiving the prestigious ASMS Award for a Distinguished Contribution in Mass Spectrometry for her pioneering work on microbial mass spectrometry.

  11. Elucidation of the mass fragmentation pathways of potato glycoalkaloids and aglycons using Orbitrap mass spectrometry.

    Science.gov (United States)

    Cahill, Michael G; Caprioli, Giovanni; Vittori, Sauro; James, Kevin J

    2010-09-01

    The mass fragmentation of potato glycoalkaloids, α-solanine and α-chaconine, and the aglycons, demissidine and solasodine were studied using the Orbitrap Fourier transform (FT) mass spectrometer. Using the linear ion trap (LIT) mass spectrometry, multistage collisional-induced dissociation (CID) experiments (MS(n)) on the [M + H](+) precursor ions were performed to aid the elucidation of the mass fragmentation pathways. In addition, higher energy collisional-induced dissociation (HCD) mass spectra were generated for these toxins at a high resolution setting [100,000 FWHM (full width at half maximum)] using the Orbitrap. This hybrid mass spectrometry instrumentation was exploited to produce MS(3) spectra by selecting MS(2) product ions, generated using LIT MS, and fragmentation using HCD. The accurate mass data in the MS(3) spectra aided the confirmation of proposed product ion formulae. The precursor and product ions from glycoalkaloids lost up to four sugars from different regions during MS(n) experiments. Mass fragmentation of the six-ring aglycons were similar, generating major product ions that resulted from cleavages at the B-rings and E-rings.

  12. Inductively coupled plasma mass spectrometry in the analysis of biological samples and pharmaceutical drugs

    Science.gov (United States)

    Ossipov, K.; Seregina, I. F.; Bolshov, M. A.

    2016-04-01

    Inductively coupled plasma mass spectrometry (ICP-MS) is widely used in the analysis of biological samples (whole blood, serum, blood plasma, urine, tissues, etc.) and pharmaceutical drugs. The shortcomings of this method related to spectral and non-spectral interferences are manifested in full measure in determination of the target analytes in these complex samples strongly differing in composition. The spectral interferences are caused by similarity of masses of the target component and sample matrix components. Non-spectral interferences are related to the influence of sample matrix components on the physicochemical processes taking place during formation and transportation of liquid sample aerosols into the plasma, on the value and spatial distribution of plasma temperature and on the transmission of the ion beam from the interface to mass spectrometer detector. The review is devoted to analysis of different mechanisms of appearance of non-spectral interferences and to ways for their minimization or elimination. Special attention is paid to the techniques of biological sample preparation, which largely determine the mechanisms of the influence of sample composition on the results of element determination. The ways of lowering non-spectral interferences by instrumental parameter tuning and application of internal standards are considered. The bibliography includes 189 references.

  13. Non-Target Screening of Veterinary Drugs Using Tandem Mass Spectrometry on SmartMass

    Science.gov (United States)

    Xia, Bing; Liu, Xin; Gu, Yu-Cheng; Zhang, Zhao-Hui; Wang, Hai-Yan; Ding, Li-Sheng; Zhou, Yan

    2013-05-01

    Non-target screening of veterinary drugs using tandem mass spectrometric data was performed on the SmartMass platform. This newly developed software uses the characteristic fragmentation patterns (CFP) to identify chemicals, especially those containing particular substructures. A mixture of 17 sulfonamides was separated by ultra performance liquid chromatography (UPLC), and SmartMass was used to process the tandem mass spectrometry (MS/MS) data acquired on an Orbitrap mass spectrometer. The data were automatically extracted, and each sulfonamide was recognized and analyzed with a prebuilt analysis rule. By using this software, over 98 % of the false candidate structures were eliminated, and all the correct structures were found within the top 10 of the ranking lists. Furthermore, SmartMass could also be used to identify slightly modified contraband drugs and metabolites with simple prebuilt rules. [Figure not available: see fulltext.

  14. Laser desorption lamp ionization source for ion trap mass spectrometry.

    Science.gov (United States)

    Wu, Qinghao; Zare, Richard N

    2015-01-01

    A two-step laser desorption lamp ionization source coupled to an ion trap mass spectrometer (LDLI-ITMS) has been constructed and characterized. The pulsed infrared (IR) output of an Nd:YAG laser (1064 nm) is directed to a target inside a chamber evacuated to ~15 Pa causing desorption of molecules from the target's surface. The desorbed molecules are ionized by a vacuum ultraviolet (VUV) lamp (filled with xenon, major wavelength at 148 nm). The resulting ions are stored and detected in a three-dimensional quadrupole ion trap modified from a Finnigan Mat LCQ mass spectrometer operated at a pressure of ≥ 0.004 Pa. The limit of detection for desorbed coronene molecules is 1.5 pmol, which is about two orders of magnitude more sensitive than laser desorption laser ionization mass spectrometry using a fluorine excimer laser (157 nm) as the ionization source. The mass spectrum of four standard aromatic compounds (pyrene, coronene, rubrene and 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine (OPC)) shows that parent ions dominate. By increasing the infrared laser power, this instrument is capable of detecting inorganic compounds. PMID:25601688

  15. Method for predicting peptide detection in mass spectrometry

    Science.gov (United States)

    Kangas, Lars [West Richland, WA; Smith, Richard D [Richland, WA; Petritis, Konstantinos [Richland, WA

    2010-07-13

    A method of predicting whether a peptide present in a biological sample will be detected by analysis with a mass spectrometer. The method uses at least one mass spectrometer to perform repeated analysis of a sample containing peptides from proteins with known amino acids. The method then generates a data set of peptides identified as contained within the sample by the repeated analysis. The method then calculates the probability that a specific peptide in the data set was detected in the repeated analysis. The method then creates a plurality of vectors, where each vector has a plurality of dimensions, and each dimension represents a property of one or more of the amino acids present in each peptide and adjacent peptides in the data set. Using these vectors, the method then generates an algorithm from the plurality of vectors and the calculated probabilities that specific peptides in the data set were detected in the repeated analysis. The algorithm is thus capable of calculating the probability that a hypothetical peptide represented as a vector will be detected by a mass spectrometry based proteomic platform, given that the peptide is present in a sample introduced into a mass spectrometer.

  16. The role of mass spectrometry in medicinal plant research.

    Science.gov (United States)

    Héthelyi, E; Tétényi, P; Dabi, E; Dános, B

    1987-11-01

    In phytochemical and chemotaxonomic research work mass spectrometry plays an outstandingly important role. Using gas chromatography/mass spectrometry (GC/MS) we established the chemotaxa of Tanacetum vulgare L. Chemotypes with essential oils containing 60-90% of artemisia ketone, carveol, dihydrocarvone, myrtenol, umbellulone, terpinen-4-ol, davanone, and Tagetes species containing various essential oils can be clearly distinguished by their spectra; we examined many variations of Tagetes erecta, T. lucida, T. minuta, T. patula and T. tenuifolia. We have identified alpha-beta-pinene-, 1,8-cineol-, linalool-, camphor-, nerol-, geraniol- and gamma-gurjonene as components of Achillea distans L. Injecting the essential oil direct from the oil-secreting organs of T. minuta plants we identified using GC/MS 6-10 and 16% eugenol from the involucral bract and hypsophyll, respectively, as well as beta-ocimene, dihydrotagetone, tagetone, Z- and E-ocimenones. In the course of studies on essential fatty acids Borago officinalis and Lappula squarrosa were selected from 70 species of the family Boraginaceae to obtain seed oil as a source of gamma-linolenic acid, and for the PG synthesis we isolated several grams of gamma-linolenic acid, as well as C18:4, i.e. octadecatetraenic acid, from L. squarrosa on the basis of the mass spectra. From the seed oil of Aquilegia vulgaris C18:3 (5) from the oil of Limnanthes dougloasii C20:1 (5) and from the seed oils of Delphinium consolida and of Tropaeolum species (T. majus, T. minus, T. peregrinum) C20:1 (11) fatty acids were identified on the basis of spectra. PMID:2962668

  17. Transitioning from Targeted to Comprehensive Mass Spectrometry Using Genetic Algorithms

    Science.gov (United States)

    Jaffe, Jacob D.; Feeney, Caitlin M.; Patel, Jinal; Lu, Xiaodong; Mani, D. R.

    2016-08-01

    Targeted proteomic assays are becoming increasingly popular because of their robust quantitative applications enabled by internal standardization, and they can be routinely executed on high performance mass spectrometry instrumentation. However, these assays are typically limited to 100s of analytes per experiment. Considerable time and effort are often expended in obtaining and preparing samples prior to targeted analyses. It would be highly desirable to detect and quantify 1000s of analytes in such samples using comprehensive mass spectrometry techniques (e.g., SWATH and DIA) while retaining a high degree of quantitative rigor for analytes with matched internal standards. Experimentally, it is facile to port a targeted assay to a comprehensive data acquisition technique. However, data analysis challenges arise from this strategy concerning agreement of results from the targeted and comprehensive approaches. Here, we present the use of genetic algorithms to overcome these challenges in order to configure hybrid targeted/comprehensive MS assays. The genetic algorithms are used to select precursor-to-fragment transitions that maximize the agreement in quantification between the targeted and the comprehensive methods. We find that the algorithm we used provided across-the-board improvement in the quantitative agreement between the targeted assay data and the hybrid comprehensive/targeted assay that we developed, as measured by parameters of linear models fitted to the results. We also found that the algorithm could perform at least as well as an independently-trained mass spectrometrist in accomplishing this task. We hope that this approach will be a useful tool in the development of quantitative approaches for comprehensive proteomics techniques.

  18. Screening Non-colored Phenolics in Red Wines using Liquid Chromatography/Ultraviolet and Mass Spectrometry/Mass Spectrometry Libraries

    Directory of Open Access Journals (Sweden)

    Changqing Duan

    2007-03-01

    Full Text Available Liquid chromatography/ultraviolet (LC/UV and mass spectrometry/mass spectrometry (MS/MS libraries containing 39 phenolic compounds were established by coupling a LC and an ion trap MS with an electrospray ionization (ESI source, operated in negative ion mode. As a result, the deprotonated [M-H]- molecule was observed for all the analyzed compounds. Using MS/MS hydroxybenzoic acid and hydroxycinnamic acids showed a loss of CO2 and production of a [M-H-44] - fragment and as expected, the UV spectra of these two compounds were affected by their chemical structures. For flavonol and flavonol glycosides, the spectra of their glycosides and aglycones produced deprotonated [M-H]- and [A-H]- species, respectively, and their UV spectra each presented two major absorption peaks. The UV spectra and MS/MS data of flavan-3-ols and stilbenes were also investigated. Using the optimized LC/MS/MS analytical conditions, the phenolic extracts from six representative wine samples were analyzed and 31 phenolic compounds were detected, 26 of which were identified by searching the LC/UV and MS/MS libraries. Finally, the presence of phenolic compounds was confirmed in different wine samples using the LC/UV and LC/MS/MS libraries.

  19. Quantitative liquid chromatography/mass spectrometry/mass spectrometry warfarin assay for in vitro cytochrome P450 studies.

    Science.gov (United States)

    Zhang, Z Y; King, B M; Wong, Y N

    2001-11-01

    A sensitive assay using high-performance liquid chromatography tandem mass spectrometry (MS/MS) has been established for the quantitative analysis of cytochrome P450 form-specific activities using warfarin as a probe substrate. Four metabolites, 6-, 7-, 8-, and 10-hydroxywarfarin, were chromatographically resolved within 10 min using gradient mobile phases. The mass spectrometry was operated under negative ionization mode. The MS/MS product ion spectra of warfarin and the metabolites were generated using collision-activated dissociation and interpreted. The abundant product ions of the metabolites were selected for quantification applying multiple reaction monitoring. Quantification was based on a quadratic or power curve of the peak area ratio of the metabolite over the internal standard against the respective concentration of the metabolite. This assay has been validated from 2 to 1000 nM for 10-hydroxywarfarin and from 2 to 5000 nM for 6-, 7-, and 8-hydroxywarfarin and successfully applied to evaluate cytochrome P450-mediated drug-drug interactions in vitro using human hepatocytes and liver microsomal preparations. PMID:11673893

  20. Transition of Iodine Analysis to Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Watrous, Matthew George [Idaho National Lab. (INL), Idaho Falls, ID (United States); Adamic, Mary Louise [Idaho National Lab. (INL), Idaho Falls, ID (United States); Olson, John Eric [Idaho National Lab. (INL), Idaho Falls, ID (United States); Baeck, D. L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Fox, R. V. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hahn, P. A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jenson, D. D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lister, T. E. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    The goal of the project, New Paradigms for Isotope Ratio Mass Spectrometry: Raising the Scientific Profile and Improved Performance for Accelerator Mass Spectrometry (AMS) and Thermal Ionization Mass Spectrometry (TIMS), is to ensure that the ongoing isotope ratio determination capability within the U.S. Department of Energy complex is the world’s best for application to nonproliferation. This report spells out the progress of Task 4, Transition of TIMS to AMS for Iodine Analysis, of the larger project. The subtasks under Task 4 and the accomplishments throughout the three year project life cycle are presented in this report. Progress was made in optimization of chemical extraction, determination of a detection limit for 127Iodine, production of standard materials for AMS analysis quality assurance, facilitation of knowledge exchange with respect to analyzing iodine on an AMS, cross comparison with a world-leading AMS laboratory, supercritical fluid extraction of iodine for AMS analysis and electrodeposition of seawater as a direct method of preparation for iodine analysis by AMS--all with the goal of minimizing the time required to stand up an AMS capability for iodine analysis of exposed air filters at INL. An effective extraction method has been developed and demonstrated for iodine analysis of exposed air filters. Innovative techniques to accomplish the cathode preparation for AMS analysis were developed and demonstrated and published. The known gap of a lack of available materials for reference standards in the analysis of iodine by AMS was filled by the preparation of homogenous materials that were calibrated against NIST materials. A minimum limit on the amount of abundant isotope in a sample was determined for AMS analysis. The knowledge exchange occurred with fantastic success. Scientists engaged the international AMS community at conferences, as well as in their laboratories for collaborative work. The supercritical fluid extraction work has positive

  1. Transition of Iodine Analysis to Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Watrous, Matthew George [Idaho National Lab. (INL), Idaho Falls, ID (United States); Adamic, Mary Louise [Idaho National Lab. (INL), Idaho Falls, ID (United States); Olson, John Eric [Idaho National Lab. (INL), Idaho Falls, ID (United States); Baeck, D. L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Fox, R. V. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hahn, P. A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Jenson, D. D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lister, T. E. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    The goal of the project, New Paradigms for Isotope Ratio Mass Spectrometry: Raising the Scientific Profile and Improved Performance for Accelerator Mass Spectrometry (AMS) and Thermal Ionization Mass Spectrometry (TIMS), is to ensure that the ongoing isotope ratio determination capability within the U.S. Department of Energy complex is the world’s best for application to nonproliferation. This report spells out the progress of Task 4, Transition of TIMS to AMS for Iodine Analysis, of the larger project. The subtasks under Task 4 and the accomplishments throughout the three year project life cycle are presented in this report. Progress was made in optimization of chemical extraction, determination of a detection limit for 127Iodine, production of standard materials for AMS analysis quality assurance, facilitation of knowledge exchange with respect to analyzing iodine on an AMS, cross comparison with a world leading AMS laboratory, supercritical fluid extraction of iodine for AMS analysis and electrodeposition of seawater as a direct method of preparation for iodine analysis by AMS. All with the goal of minimizing the time required to stand up an AMS capability for iodine analysis of exposed air filters at INL. An effective extraction method has been developed and demonstrated for iodine analysis of exposed air filters. Innovative techniques to accomplish the cathode preparation for AMS analysis were developed and demonstrated and published. The known gap of a lack of available materials for reference standards in the analysis of iodine by AMS was filled by the preparation of homogenous materials that were calibrated against NIST materials. A minimum limit on the amount of abundant isotope in a sample was determined for AMS analysis. The knowledge exchange occurred with fantastic success. Scientists engaged the international AMS community at conferences, as well as in their laboratories for collaborative work. The supercritical fluid extraction work has positive

  2. Matrix effects in inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiaoshan

    1995-07-07

    The inductively coupled plasma is an electrodeless discharge in a gas (usually Ar) at atmospheric pressure. Radio frequency energy generated by a RF power source is inductively coupled to the plasma gas through a water cooled load coil. In ICP-MS the {open_quotes}Fassel{close_quotes} TAX quartz torch commonly used in emission is mounted horizontally. The sample aerosol is introduced into the central flow, where the gas kinetic temperature is about 5000 K. The aerosol is vaporized, atomized, excited and ionized in the plasma, and the ions are subsequently extracted through two metal apertures (sampler and skimmer) into the mass spectrometer. In ICP-MS, the matrix effects, or non-spectroscopic interferences, can be defined as the type of interferences caused by dissolved concomitant salt ions in the solution. Matrix effects can be divided into two categories: (1) signal drift due to the deposition of solids on the sampling apertures; and/or (2) signal suppression or enhancement by the presence of the dissolved salts. The first category is now reasonably understood. The dissolved salts, especially refractory oxides, tend to deposit on the cool tip of the sampling cone. The clogging of the orifices reduces the ion flow into the ICP-MS, lowers the pressure in the first stage of ICP-MS, and enhances the level of metal oxide ions. Because the extent of the clogging increases with the time, the signal drifts down. Even at the very early stage of the development of ICP-MS, matrix effects had been observed. Houk et al. found out that the ICP-MS was not tolerant to solutions containing significant amounts of dissolved solids.

  3. High mass accuracy and high mass resolving power FT-ICR secondary ion mass spectrometry for biological tissue imaging

    NARCIS (Netherlands)

    Smith, D.F.; Kiss, A.; Leach, F.E.; Robinson, E.W.; Paša-Tolić, L.; Heeren, R.M.A.

    2013-01-01

    Biological tissue imaging by secondary ion mass spectrometry has seen rapid development with the commercial availability of polyatomic primary ion sources. Endogenous lipids and other small bio-molecules can now be routinely mapped on the sub-micrometer scale. Such experiments are typically performe

  4. Size segregated aerosol mass concentration measurements over the Arabian Sea during ICARB

    Indian Academy of Sciences (India)

    Vijayakumar S Nair; K Krishna Moorthy; S Suresh Babu; K Narasimhulu; L Siva Sankara Reddy; R Ramakrishna Reddy; K Rama Gopal; V Sreekanth; B L Madhavan; K Niranjan

    2008-07-01

    Mass concentration and mass size distribution of total (composite) aerosols near the surface are essential inputs needed in developing aerosol models for radiative forcing estimation as well as to infer the environment and air quality. Using extensive measurements onboard the oceanographic research vessel, Sagar Kanya, during its cruise SK223B in the second phase of the ocean segment of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB), the spatial distribution of the mass concentration and mass size distribution of near-surface aerosols are examined for the first time over the entire Arabian Sea, going as far as 58°E and 22°N, within a span of 26 days. In general, the mass concentrations () were found to be low with the mean value for the entire Arabian Sea being 16.7 ± 7 g m−3; almost 1/2 of the values reported in some of the earlier campaigns. Coarse mode aerosols contributed, on an average, 58% to the total mass, even though at a few pockets accumulation mode contribution dominated. Spatially, significant variations were observed over central and northern Arabian Sea as well as close to the west coast of India. In central Arabian Sea, even though the was quite low, contribution of accumulation aerosols to the total mass concentration was greater than 50%. Effective radius, a parameter important in determining scattering properties of aerosol size distribution, varied between 0.07 and 0.4 m with a mean value of 0.2 m. Number size distributions, deduced from the mass size distributions, were approximated to inverse power-law form and the size indices () were estimated. It was found to vary in the range 3.9 to 4.2 with a mean value of 4.0 for the entire oceanic region. Extinction coefficients, estimated using the number-size distributions, were well-correlated with the accumulation mode mass concentration with a correlation coefficient of 0.82.

  5. The use of mass spectrometry to analyze dried blood spots.

    Science.gov (United States)

    Wagner, Michel; Tonoli, David; Varesio, Emmanuel; Hopfgartner, Gérard

    2016-01-01

    Dried blood spots (DBS) typically consist in the deposition of small volumes of capillary blood onto dedicated paper cards. Comparatively to whole blood or plasma samples, their benefits rely in the fact that sample collection is easier and that logistic aspects related to sample storage and shipment can be relatively limited, respectively, without the need of a refrigerator or dry ice. Originally, this approach has been developed in the sixties to support the analysis of phenylalanine for the detection of phenylketonuria in newborns using bacterial inhibition test. In the nineties tandem mass spectrometry was established as the detection technique for phenylalanine and tyrosine. DBS became rapidly recognized for their clinical value: they were widely implemented in pediatric settings with mass spectrometric detection, and were closely associated to the debut of newborn screening (NBS) programs, as a part of public health policies. Since then, sample collection on paper cards has been explored with various analytical techniques in other areas more or less successfully regarding large-scale applications. Moreover, in the last 5 years a regain of interest for DBS was observed and originated from the bioanalytical community to support drug development (e.g., PK studies) or therapeutic drug monitoring mainly. Those recent applications were essentially driven by improved sensitivity of triple quadrupole mass spectrometers. This review presents an overall view of all instrumental and methodological developments for DBS analysis with mass spectrometric detection, with and without separation techniques. A general introduction to DBS will describe their advantages and historical aspects of their emergence. A second section will focus on blood collection, with a strong emphasis on specific parameters that can impact quantitative analysis, including chromatographic effects, hematocrit effects, blood effects, and analyte stability. A third part of the review is dedicated to

  6. Functional Groups and Structural Insights of Water-Soluble Organic Carbon using Ultrahigh Resolution FT-ICR Tandem Mass Spectrometry

    Science.gov (United States)

    Mazzoleni, L. R.; Habib, D.; Zhao, Y.; Dalbec, M.; Samburova, V.; Hallar, G.; Zielinska, B.; Lowenthal, D.

    2013-12-01

    Water-soluble organic carbon (WSOC) is a complex mixture of thousands of organic compounds which may have significant influence on the climate-relevant properties of atmospheric aerosols. An improved understanding of the molecular composition of WSOC is needed to evaluate the effect of aerosol composition upon aerosol physical properties. Products of gas phase, aqueous phase and particle phase reactions contribute to pre-existing aerosol organic mass or nucleate new aerosol particles. Thus, ambient aerosols carry a complex array of WSOC components with variable chemical signatures depending upon its origin and aerosol life-cycle processes. In this work, ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to characterize aerosol WSOC collected during the summer of 2010 at the Storm Peak Laboratory (3210 m a.s.l.) near Steamboat Springs, CO. Approximately 4000 molecular formulas were assigned in the mass range of m/z 100-800 after negative-ion electrospray ionization. The observed trends indicate significant non-oxidative accretion reaction pathways for the formation of high molecular weight WSOC components closely associated with terpene ozonolysis secondary organic aerosol (SOA). The aerosol WSOC was further characterized using ultrahigh resolution tandem MS analysis with infrared multiphoton dissociation to determine the functional groups and structural properties of 1700 WSOC species up to m/z 600. Due to the complex nature of the WSOC, multiple precursor ions were simultaneously fragmented. The exact mass measurements of the precursor and product ions facilitated molecular formula assignments and matching of neutral losses. The most important neutral losses are CO2, H2O, CH3OH, HNO3, CH3NO3, SO3 and SO4. The presence and frequency of these losses indicate the type of functional groups contained in the precursor structures. Consistent with the acidic nature of WSOC compounds, the most frequently observed losses

  7. New high temperature plasmas and sample introduction systems for analytical atomic emission and mass spectrometry. Progress report, January 1, 1990--December 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Montaser, A.

    1992-09-01

    New high temperature plasmas and new sample introduction systems are explored for rapid elemental and isotopic analysis of gases, solutions, and solids using mass spectrometry and atomic emission spectrometry. Emphasis was placed on atmospheric pressure He inductively coupled plasmas (ICP) suitable for atomization, excitation, and ionization of elements; simulation and computer modeling of plasma sources with potential for use in spectrochemical analysis; spectroscopic imaging and diagnostic studies of high temperature plasmas, particularly He ICP discharges; and development of new, low-cost sample introduction systems, and examination of techniques for probing the aerosols over a wide range. Refs., 14 figs. (DLC)

  8. Evaluation of correction method for mass discrimination effect in multiple collector inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    This paper describes advances in isotopic measurements that have been made with an inductively coupled plasma source magnetic sector multiple collector mass spectrometer (MC-ICP-MS) and presents results of new experiments aimed at further evaluating the instrumental capability as well as the correction technique for the mass discrimination effects. The ability to correct for the mass discrimination effect using a second element of similar mass and very high sensitivity for elements that are otherwise difficult to ionize gives this instrument major advantages over other conventional techniques for isotopic measurements. The isotopic data obtained by MC-ICP-MS clearly demonstrate potential as a new technique to produce precise and reproducible isotopic data for the elements that are difficult to measure by thermal ionization mass spectrometry (TIMS). (author)

  9. Accelerator mass spectrometry programme at BARC-TIFR pelletron accelerator

    International Nuclear Information System (INIS)

    Accelerator based mass spectrometry (ABMs) is an ultra sensitive means of counting individual atoms having sufficiently long half life and available in small amount. The 14 U D Pelletron Accelerator is an ideal machine to carry out ABMs studies with heavy isotopes like 36Cl and 129I. Cosmogenic radio isotope 36Cl is widely being detected using ABMs as it has got applications in ground water research, radioactive waste management, atmospheric 36Cl transport mechanism studies of Arctic Alpine ice core etc. As a part of the ongoing ABMs programme at 14UD Pelletron Accelerator Facility at Mumbai, a segmented gas detector developed for identification of 36Cl was tested for performance. Recently a beam chopper required for this measurement has been developed. Further progress made in this programme is discussed in this paper. (author)

  10. Studies of Al metabolism in animal by accelerator mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    WangNa-Xiu; ZhuHan-Min; 等

    1997-01-01

    The correlation between Al metabolism and senile dementia in animal has been studied by AMS(accelerator mass spectrometry).Three groups of laboratory rats were fed with normal food.food with high Al content,and with enriched Ca and Mg together with high Al,respectively for six to eight months.Mapping test was made to recored th degree of wisdom degeneration.Half of the rats were sacrificed and Al contents in various organs were measured by atomic absorption spectroscopy.The rest were injected with 26Al,killed after 5,10,15,25,and 35d and 26Al contents measured by AMS.The distribution of Al as well as the correlation among the accumulation of 26Al,and the existed Al content and dementia was studied.

  11. Acetonitrile Ion Suppression in Atmospheric Pressure Ionization Mass Spectrometry

    Science.gov (United States)

    Colizza, Kevin; Mahoney, Keira E.; Yevdokimov, Alexander V.; Smith, James L.; Oxley, Jimmie C.

    2016-11-01

    Efforts to analyze trace levels of cyclic peroxides by liquid chromatography/mass spectrometry gave evidence that acetonitrile suppressed ion formation. Further investigations extended this discovery to ketones, linear peroxides, esters, and possibly many other types of compounds, including triazole and menadione. Direct ionization suppression caused by acetonitrile was observed for multiple adduct types in both electrospray ionization and atmospheric pressure chemical ionization. The addition of only 2% acetonitrile significantly decreased the sensitivity of analyte response. Efforts to identify the mechanism were made using various nitriles. The ion suppression was reduced by substitution of an acetonitrile hydrogen with an electron-withdrawing group, but was exacerbated by electron-donating or steric groups adjacent to the nitrile. Although current theory does not explain this phenomenon, we propose that polar interactions between the various functionalities and the nitrile may be forming neutral aggregates that manifest as ionization suppression.

  12. Attomole quantitation of protein separations with accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, J S; Grant, P G; Buccholz, B A; Dingley, K; Turteltaub, K W

    2000-12-15

    Quantification of specific proteins depends on separation by chromatography or electrophoresis followed by chemical detection schemes such as staining and fluorophore adhesion. Chemical exchange of short-lived isotopes, particularly sulfur, is also prevalent despite the inconveniences of counting radioactivity. Physical methods based on isotopic and elemental analyses offer highly sensitive protein quantitation that has linear response over wide dynamic ranges and is independent of protein conformation. Accelerator mass spectrometry quantifies long-lived isotopes such as 14C to sub-attomole sensitivity. We quantified protein interactions with small molecules such as toxins, vitamins, and natural biochemicals at precisions of 1-5% . Micro-proton-induced-xray-emission quantifies elemental abundances in separated metalloprotein samples to nanogram amounts and is capable of quantifying phosphorylated loci in gels. Accelerator-based quantitation is a possible tool for quantifying the genome translation into proteome.

  13. Dating Studies of Elephant Tusks Using Accelerator Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Sideras-Haddad, E; Brown, T A

    2002-10-03

    A new method for determining the year of birth, the year of death, and hence, the age at death, of post-bomb and recently deceased elephants has been developed. The technique is based on Accelerator Mass Spectrometry radiocarbon analyses of small-sized samples extracted from along the length of a ge-line of an elephant tusk. The measured radiocarbon concentrations in the samples from a tusk can be compared to the {sup 14}C atmospheric bomb-pulse curve to derive the growth years of the initial and final samples from the tusk. Initial data from the application of this method to two tusks will be presented. Potentially, the method may play a significant role in wildlife management practices of African national parks. Additionally, the method may contribute to the underpinnings of efforts to define new international trade regulations, which could, in effect, decrease poaching and the killing of very young animals.

  14. Mass Spectrometry-Based Label-Free Quantitative Proteomics

    Directory of Open Access Journals (Sweden)

    Wenhong Zhu

    2010-01-01

    Full Text Available In order to study the differential protein expression in complex biological samples, strategies for rapid, highly reproducible and accurate quantification are necessary. Isotope labeling and fluorescent labeling techniques have been widely used in quantitative proteomics research. However, researchers are increasingly turning to label-free shotgun proteomics techniques for faster, cleaner, and simpler results. Mass spectrometry-based label-free quantitative proteomics falls into two general categories. In the first are the measurements of changes in chromatographic ion intensity such as peptide peak areas or peak heights. The second is based on the spectral counting of identified proteins. In this paper, we will discuss the technologies of these label-free quantitative methods, statistics, available computational software, and their applications in complex proteomics studies.

  15. Temperature-programmed desorption for membrane inlet mass spectrometry

    DEFF Research Database (Denmark)

    Ketola, R.A.; Grøn, C.; Lauritsen, F.R.

    1998-01-01

    We present a novel technique for analyzing volatile organic compounds in air samples using a solid adsorbent together with temperature-programmed desorption and subsequent detection by membrane inlet mass spectrometry (TPD-MIMS). The new system has the advantage of a fast separation of compounds...... on the strength of the interaction between the individual compound and the adsorbent. The helium stream carries the desorbed compounds to a membrane inlet (90 degrees C) equipped with a thin (25 pm) silicone membrane. The thin membrane and the high temperature of the membrane inlet allows most volatile compounds...... prior to the detection by MIMS. The gaseous sample is simply adsorbed on the adsorbent, which is then rapidly heated from 30 degrees C to 250 degrees C at a rate of 50 degrees C/min, Trapped organic compounds are released from the adsorbent into a helium stream at different temperatures depending...

  16. Mass spectrometry study of the sublimation of aliphatic dipeptides

    Science.gov (United States)

    Badelin, V. G.; Tyunina, E. Yu.; Krasnov, A. V.; Tyunina, V. V.; Giricheva, N. I.; Girichev, A. V.

    2012-03-01

    The sublimation of glycyl-L-α-alanine (Gly-Ala), L-α-alanyl-L-α-alanine (Ala-Ala), and DL-α-alanyl-DL-α-valine (Ala-Val) aliphatic dipeptides is studied by electron ionization mass spectrometry in combination with Knudsen effusion. The temperature range in which substances sublime as monomer molecular forms is determined. Enthalpies of sublimation Δs H°( T) are determined for Gly-Ala, Ala-Ala, and Ala-Val. It is shown that the enthalpy of sublimation of dipeptides increases with an increase in the side hydrocarbon radical. The unknown Δs H°(298) values for 17 amino acids and nine dipeptides are estimated using the proposed "structure-property" correlation model, in which the geometry and electron characteristics of molecules are used as structural descriptors.

  17. Polymer architectures via mass spectrometry and hyphenated techniques: A review.

    Science.gov (United States)

    Crotty, Sarah; Gerişlioğlu, Selim; Endres, Kevin J; Wesdemiotis, Chrys; Schubert, Ulrich S

    2016-08-17

    This review covers the application of mass spectrometry (MS) and its hyphenated techniques to synthetic polymers of varying architectural complexities. The synthetic polymers are discussed as according to their architectural complexity from linear homopolymers and copolymers to stars, dendrimers, cyclic copolymers and other polymers. MS and tandem MS (MS/MS) has been extensively used for the analysis of synthetic polymers. However, the increase in structural or architectural complexity can result in analytical challenges that MS or MS/MS cannot overcome alone. Hyphenation to MS with different chromatographic techniques (2D × LC, SEC, HPLC etc.), utilization of other ionization methods (APCI, DESI etc.) and various mass analyzers (FT-ICR, quadrupole, time-of-flight, ion trap etc.) are applied to overcome these challenges and achieve more detailed structural characterizations of complex polymeric systems. In addition, computational methods (software: MassChrom2D, COCONUT, 2D maps etc.) have also reached polymer science to facilitate and accelerate data interpretation. Developments in technology and the comprehension of different polymer classes with diverse architectures have significantly improved, which allow for smart polymer designs to be examined and advanced. We present specific examples covering diverse analytical aspects as well as forthcoming prospects in polymer science. PMID:27286765

  18. Toward laser ablation Accelerator Mass Spectrometry of actinides

    Science.gov (United States)

    Pardo, R. C.; Kondev, F. G.; Kondrashev, S.; Nair, C.; Palchan, T.; Scott, R.; Seweryniak, D.; Vondrasek, R.; Paul, M.; Collon, P.; Deibel, C.; Youinou, G.; Salvatores, M.; Palmotti, G.; Berg, J.; Fonnesbeck, J.; Imel, G.

    2013-01-01

    A project to measure neutron capture cross sections of a number of actinides in a reactor environment by Accelerator Mass Spectrometry (AMS) at the ATLAS facility of Argonne National Laboratory is underway. This project will require the precise and accurate measurement of produced actinide isotopes in many (>30) samples irradiated in the Advanced Test Reactor at Idaho National Laboratory with neutron fluxes having different energy distributions. The AMS technique at ATLAS is based on production of highly-charged positive ions in an electron cyclotron resonance (ECR) ion source followed by acceleration in the ATLAS linac and mass-to-charge (m/q) measurement at the focus of the Fragment Mass Analyzer. Laser ablation was selected as the method of feeding the actinide material into the ion source because we expect it will have higher efficiency and lower chamber contamination than either the oven or sputtering techniques, because of a much narrower angular distribution of emitted material. In addition, a new multi-sample holder/changer to allow quick change between samples and a computer-controlled routine allowing fast tuning of the accelerator for different beams, are being developed. An initial test run studying backgrounds, detector response, and accelerator scaling repeatability was conducted in December 2010. The project design, schedule, and results of the initial test run to study backgrounds are discussed.

  19. Cloud parallel processing of tandem mass spectrometry based proteomics data.

    Science.gov (United States)

    Mohammed, Yassene; Mostovenko, Ekaterina; Henneman, Alex A; Marissen, Rob J; Deelder, André M; Palmblad, Magnus

    2012-10-01

    Data analysis in mass spectrometry based proteomics struggles to keep pace with the advances in instrumentation and the increasing rate of data acquisition. Analyzing this data involves multiple steps requiring diverse software, using different algorithms and data formats. Speed and performance of the mass spectral search engines are continuously improving, although not necessarily as needed to face the challenges of acquired big data. Improving and parallelizing the search algorithms is one possibility; data decomposition presents another, simpler strategy for introducing parallelism. We describe a general method for parallelizing identification of tandem mass spectra using data decomposition that keeps the search engine intact and wraps the parallelization around it. We introduce two algorithms for decomposing mzXML files and recomposing resulting pepXML files. This makes the approach applicable to different search engines, including those relying on sequence databases and those searching spectral libraries. We use cloud computing to deliver the computational power and scientific workflow engines to interface and automate the different processing steps. We show how to leverage these technologies to achieve faster data analysis in proteomics and present three scientific workflows for parallel database as well as spectral library search using our data decomposition programs, X!Tandem and SpectraST.

  20. Electrospray ionisation mass spectrometry: principles and clinical applications.

    Science.gov (United States)

    Ho, C S; Lam, C W K; Chan, M H M; Cheung, R C K; Law, L K; Lit, L C W; Ng, K F; Suen, M W M; Tai, H L

    2003-01-01

    This mini-review provides a general understanding of electrospray ionisation mass spectrometry (ESI-MS) which has become an increasingly important technique in the clinical laboratory for structural study or quantitative measurement of metabolites in a complex biological sample. The first part of the review explains the electrospray ionisation process, design of mass spectrometers with separation capability, characteristics of the mass spectrum, and practical considerations in quantitative analysis. The second part then focuses on some clinical applications. The capability of ESI-tandem-MS in measuring bio-molecules sharing similar molecular structures makes it particularly useful in screening for inborn errors of amino acid, fatty acid, purine, pyrimidine metabolism and diagnosis of galactosaemia and peroxisomal disorders. Electrospray ionisation is also efficient in generating cluster ions for structural elucidation of macromolecules. This has fostered a new and improved approach (vs electrophoresis) for identification and quantification of haemoglobin variants. With the understanding of glycohaemoglobin structure, an IFCC reference method for glycohaemoglobin assay has been established using ESI-MS. It represents a significant advancement for the standardisation of HbA1c in diabetic monitoring. With its other applications such as in therapeutic drug monitoring, ESI-MS will continue to exert an important influence in the future development and organisation of the clinical laboratory service.

  1. U-series dating using thermal ionisation mass spectrometry (TIMS)

    International Nuclear Information System (INIS)

    U-series dating is based on the decay of the two long-lived isotopes238U(τ1/2=4.47 x 109 years) and 235U (τ1/2 0.7 x 109 years). 238U and its intermediate daughter isotopes 234U (τ1/2 = 245.4 ka) and 230Th (τ1/2 = 75.4 ka) have been the main focus of recently developed mass spectrometric techniques (Edwards et al., 1987) while the other less frequently used decay chain is based on the decay 235U to 231Pa (τ1/2 = 32.8 ka). Both the 238U and 235U decay chains terminate at the stable isotopes 206Pb and 207Pb respectively. Thermal ionization mass spectrometry (TIMS) has a number of inherent advantages, mainly the ability to measure isotopic ratios at high precision on relatively small samples. In spite of these now obvious advantages, it is only since the mid-1980's when Chen et al., (1986) made the first precise measurements of 234U and 232Th in seawater followed by Edwards et al., (1987) who made combined 234U-230Th measurements, was the full potential of mass spectrometric methods first realised. Several examples are given to illustrate various aspects of TIMS U-series

  2. Dynamically multiplexed ion mobility time-of-flight mass spectrometry.

    Science.gov (United States)

    Belov, Mikhail E; Clowers, Brian H; Prior, David C; Danielson, William F; Liyu, Andrei V; Petritis, Brianne O; Smith, Richard D

    2008-08-01

    Ion mobility spectrometry-time-of-flight mass spectrometry (IMS-TOFMS) has been increasingly used in analysis of complex biological samples. A major challenge is to transform IMS-TOFMS to a high-sensitivity, high-throughput platform, for example, for proteomics applications. In this work, we have developed and integrated three advanced technologies, including efficient ion accumulation in an ion funnel trap prior to IMS separation, multiplexing (MP) of ion packet introduction into the IMS drift tube, and signal detection with an analog-to-digital converter, into the IMS-TOFMS system for the high-throughput analysis of highly complex proteolytic digests of, for example, blood plasma. To better address variable sample complexity, we have developed and rigorously evaluated a novel dynamic MP approach that ensures correlation of the analyzer performance with an ion source function and provides the improved dynamic range and sensitivity throughout the experiment. The MP IMS-TOFMS instrument has been shown to reliably detect peptides at a concentration of 1 nM in the presence of a highly complex matrix, as well as to provide a 3 orders of magnitude dynamic range and a mass measurement accuracy of better than 5 ppm. When matched against human blood plasma database, the detected IMS-TOF features were found to yield approximately 700 unique peptide identifications at a false discovery rate (FDR) of approximately 7.5%. Accounting for IMS information gave rise to a projected FDR of approximately 4%. Signal reproducibility was found to be greater than 80%, while the variations in the number of unique peptide identifications were <15%. A single sample analysis was completed in 15 min that constitutes almost 1 order of magnitude improvement compared to a more conventional LC-MS approach. PMID:18582088

  3. Human folate metabolism using 14C-accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Clifford, A. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Arjomand, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Duecker, S. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Johnson, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schneider, P. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zulim, R. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bucholz, B. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Vogel, J. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    1999-03-25

    Folate is a water soluble vitamin required for optimal health, growth and development. It occurs naturally in various states of oxidation of the pteridine ring and with varying lengths to its glutamate chain. Folates function as one-carbon donors through methyl transferase catalyzed reactions. Low-folate diets, especially by those with suboptimal methyltransferase activity, are associated with increased risk of neural tube birth defects in children, hyperhomocysteinemic heart disease, and cancer in adults. Rapidly dividing (neoplastic) cells have a high folate need for DNA synthesis. Chemical analogs of folate (antifolates) that interfere with folate metabolism are used as therapeutic agents in cancer treatment. Although much is known about folate chemistry, metabolism of this vitamin in vivo in humans is not well understood. Since folate levels in blood and tissues are very low and methods to measure them are inadequate, the few previous studies that have examined folate metabolism used large doses of radiolabeled folic acid in patients with Hodgkin's disease and cancer (Butterworth et al. 1969, Krumdieck et al. 1978). A subsequent protocol using deuterated folic acid was also insufficiently sensitive to trace a physiologic folate dose (Stites et al. 1997). Accelerator mass spectrometry (AMS) is an emerging bioanalytical tool that overcomes the limitations of traditional mass spectrometry and of decay counting of long lived radioisotopes (Vogel et al. 1995). AMS can detect attomolar concentrations of 14 C in milligram-sized samples enabling in vivo radiotracer studies in healthy humans. We used AMS to study the metabolism of a physiologic 80 nmol oral dose of 14 C-folic acid (1/6 US RDA) by measuring the 14 C-folate levels in serial plasma, urine and feces samples taken over a 150-day period after dosing a healthy adult volunteer.

  4. Paper-Based Electrochemical Cell Coupled to Mass Spectrometry

    Science.gov (United States)

    Liu, Yao-Min; Perry, Richard H.

    2015-08-01

    On-line coupling of electrochemistry (EC) to mass spectrometry (MS) is a powerful approach for identifying intermediates and products of EC reactions in situ. In addition, EC transformations have been used to increase ionization efficiency and derivatize analytes prior to MS, improving sensitivity and chemical specificity. Recently, there has been significant interest in developing paper-based electroanalytical devices as they offer convenience, low cost, versatility, and simplicity. This report describes the development of tubular and planar paper-based electrochemical cells (P-EC) coupled to sonic spray ionization (SSI) mass spectrometry (P-EC/SSI-MS). The EC cells are composed of paper sandwiched between two mesh stainless steel electrodes. Analytes and reagents can be added directly to the paper substrate along with electrolyte, or delivered via the SSI microdroplet spray. The EC cells are decoupled from the SSI source, allowing independent control of electrical and chemical parameters. We utilized P-EC/SSI-MS to characterize various EC reactions such as oxidations of cysteine, dopamine, polycyclic aromatic hydrocarbons, and diphenyl sulfide. Our results show that P-EC/SSI-MS has the ability to increase ionization efficiency, to perform online EC transformations, and to capture intermediates of EC reactions with a response time on the order of hundreds of milliseconds. The short response time allowed detection of a deprotonated diphenyl sulfide intermediate, which experimentally confirms a previously proposed mechanism for EC oxidation of diphenyl sulfide to pseudodimer sulfonium ion. This report introduces paper-based EC/MS via development of two device configurations (tubular and planar electrodes), as well as discusses the capabilities, performance, and limitations of the technique.

  5. Tissue proteomics using chemical immobilization and mass spectrometry.

    Science.gov (United States)

    Shah, Punit; Zhang, Bai; Choi, Caitlin; Yang, Shuang; Zhou, Jianying; Harlan, Robert; Tian, Yuan; Zhang, Zhen; Chan, Daniel W; Zhang, Hui

    2015-01-15

    Proteomics analysis is important for characterizing tissues to gain biological and pathological insights, which could lead to the identification of disease-associated proteins for disease diagnostics or targeted therapy. However, tissues are commonly embedded in optimal cutting temperature medium (OCT) or are formalin-fixed and paraffin-embedded (FFPE) in order to maintain tissue morphology for histology evaluation. Although several tissue proteomic analyses have been performed on FFPE tissues using advanced mass spectrometry (MS) technologies, high-throughput proteomic analysis of OCT-embedded tissues has been difficult due to the interference of OCT in the MS analysis. In addition, molecules other than proteins present in tissues further complicate tissue proteomic analysis. Here, we report the development of a method using chemical immobilization of proteins for peptide extraction (CIPPE). In this method, proteins are chemically immobilized onto a solid support; interferences from tissues and OCT embedding are removed by extensive washing of proteins conjugated on the solid support. Peptides are then released from the solid phase by proteolysis, enabling MS analysis. This method was first validated by eliminating OCT interference from a standard protein, human serum albumin, where all of the unique peaks contributed by OCT contamination were eradicated. Finally, this method was applied for the proteomic analysis of frozen and OCT-embedded tissues using iTRAQ (isobaric tag for relative and absolute quantitation) labeling and two-dimensional liquid chromatography tandem mass spectrometry. The data showed reproducible extraction and quantitation of 10,284 proteins from 3996 protein groups and a minimal impact of OCT embedding on the analysis of the global proteome of the stored tissue samples. PMID:25283129

  6. Paper-Based Electrochemical Cell Coupled to Mass Spectrometry.

    Science.gov (United States)

    Liu, Yao-Min; Perry, Richard H

    2015-10-01

    On-line coupling of electrochemistry (EC) to mass spectrometry (MS) is a powerful approach for identifying intermediates and products of EC reactions in situ. In addition, EC transformations have been used to increase ionization efficiency and derivatize analytes prior to MS, improving sensitivity and chemical specificity. Recently, there has been significant interest in developing paper-based electroanalytical devices as they offer convenience, low cost, versatility, and simplicity. This report describes the development of tubular and planar paper-based electrochemical cells (P-EC) coupled to sonic spray ionization (SSI) mass spectrometry (P-EC/SSI-MS). The EC cells are composed of paper sandwiched between two mesh stainless steel electrodes. Analytes and reagents can be added directly to the paper substrate along with electrolyte, or delivered via the SSI microdroplet spray. The EC cells are decoupled from the SSI source, allowing independent control of electrical and chemical parameters. We utilized P-EC/SSI-MS to characterize various EC reactions such as oxidations of cysteine, dopamine, polycyclic aromatic hydrocarbons, and diphenyl sulfide. Our results show that P-EC/SSI-MS has the ability to increase ionization efficiency, to perform online EC transformations, and to capture intermediates of EC reactions with a response time on the order of hundreds of milliseconds. The short response time allowed detection of a deprotonated diphenyl sulfide intermediate, which experimentally confirms a previously proposed mechanism for EC oxidation of diphenyl sulfide to pseudodimer sulfonium ion. This report introduces paper-based EC/MS via development of two device configurations (tubular and planar electrodes), as well as discusses the capabilities, performance, and limitations of the technique. PMID:26311335

  7. Tissue proteomics using chemical immobilization and mass spectrometry.

    Science.gov (United States)

    Shah, Punit; Zhang, Bai; Choi, Caitlin; Yang, Shuang; Zhou, Jianying; Harlan, Robert; Tian, Yuan; Zhang, Zhen; Chan, Daniel W; Zhang, Hui

    2015-01-15

    Proteomics analysis is important for characterizing tissues to gain biological and pathological insights, which could lead to the identification of disease-associated proteins for disease diagnostics or targeted therapy. However, tissues are commonly embedded in optimal cutting temperature medium (OCT) or are formalin-fixed and paraffin-embedded (FFPE) in order to maintain tissue morphology for histology evaluation. Although several tissue proteomic analyses have been performed on FFPE tissues using advanced mass spectrometry (MS) technologies, high-throughput proteomic analysis of OCT-embedded tissues has been difficult due to the interference of OCT in the MS analysis. In addition, molecules other than proteins present in tissues further complicate tissue proteomic analysis. Here, we report the development of a method using chemical immobilization of proteins for peptide extraction (CIPPE). In this method, proteins are chemically immobilized onto a solid support; interferences from tissues and OCT embedding are removed by extensive washing of proteins conjugated on the solid support. Peptides are then released from the solid phase by proteolysis, enabling MS analysis. This method was first validated by eliminating OCT interference from a standard protein, human serum albumin, where all of the unique peaks contributed by OCT contamination were eradicated. Finally, this method was applied for the proteomic analysis of frozen and OCT-embedded tissues using iTRAQ (isobaric tag for relative and absolute quantitation) labeling and two-dimensional liquid chromatography tandem mass spectrometry. The data showed reproducible extraction and quantitation of 10,284 proteins from 3996 protein groups and a minimal impact of OCT embedding on the analysis of the global proteome of the stored tissue samples.

  8. Advanced capabilities for in situ planetary mass spectrometry

    Science.gov (United States)

    Arevalo, R. D., Jr.; Mahaffy, P. R.; Brinckerhoff, W. B.; Getty, S.; Benna, M.; van Amerom, F. H. W.; Danell, R.; Pinnick, V. T.; Li, X.; Grubisic, A.; Cornish, T.; Hovmand, L.

    2015-12-01

    NASA GSFC has delivered highly capable quadrupole mass spectrometers (QMS) for missions to Venus (Pioneer Venus), Jupiter (Galileo), Saturn/Titan (Cassini-Huygens), Mars (MSL and MAVEN), and the Moon (LADEE). Our understanding of the Solar System has been expanded significantly by these exceedingly versatile yet low risk and cost efficient instruments. GSFC has developed more recently a suite of advanced instrument technologies promising enhanced science return while selectively leveraging heritage designs. Relying on a traditional precision QMS, the Analysis of Gas Evolved from Samples (AGES) instrument measures organic inventory, determines exposure age and establishes the absolute timing of deposition/petrogenesis of interrogated samples. The Mars Organic Molecule Analyzer (MOMA) aboard the ExoMars 2018 rover employs a two-dimensional ion trap, built analogously to heritage QMS rod assemblies, which can support dual ionization sources, selective ion enrichment and tandem mass spectrometry (MS/MS). The same miniaturized analyzer serves as the core of the Linear Ion Trap Mass Spectrometer (LITMS) instrument, which offers negative ion detection (switchable polarity) and an extended mass range (>2000 Da). Time-of-flight mass spectrometers (TOF-MS) have been interfaced to a range of laser sources to progress high-sensitivity laser ablation and desorption methods for analysis of inorganic and non-volatile organic compounds, respectively. The L2MS (two-step laser mass spectrometer) enables the desorption of neutrals and/or prompt ionization at IR (1.0 up to 3.1 µm, with an option for tunability) or UV wavelengths (commonly 266 or 355 nm). For the selective ionization of specific classes of organics, such as aromatic hydrocarbons, a second UV laser may be employed to decouple the desorption and ionization steps and limit molecular fragmentation. Mass analyzers with substantially higher resolving powers (up to m/Δm > 100,000), such as the Advanced Resolution Organic

  9. Examining the Influence of Phosphorylation on Peptide Ion Structure by Ion Mobility Spectrometry-Mass Spectrometry.

    Science.gov (United States)

    Glover, Matthew S; Dilger, Jonathan M; Acton, Matthew D; Arnold, Randy J; Radivojac, Predrag; Clemmer, David E

    2016-05-01

    Ion mobility spectrometry-mass spectrometry (IMS-MS) techniques are used to study the general effects of phosphorylation on peptide structure. Cross sections for a library of 66 singly phosphorylated peptide ions from 33 pairs of positional isomers, and unmodified analogues were measured. Intrinsic size parameters (ISPs) derived from these measurements yield calculated collision cross sections for 85% of these phosphopeptide sequences that are within ±2.5% of experimental values. The average ISP for the phosphoryl group (0.64 ± 0.05) suggests that in general this moiety forms intramolecular interactions with the neighboring residues and peptide backbone, resulting in relatively compact structures. We assess the capability of ion mobility to separate positional isomers (i.e., peptide sequences that differ only in the location of the modification) and find that more than half of the isomeric pairs have >1% difference in collision cross section. Phosphorylation is also found to influence populations of structures that differ in the cis/trans orientation of Xaa-Pro peptide bonds. Several sequences with phosphorylated Ser or Thr residues located N-terminally adjacent to Pro residues show fewer conformations compared to the unmodified sequences. Graphical Abstract ᅟ. PMID:26860087

  10. Analysis of explosives using corona discharge ionization combined with ion mobility spectrometry-mass spectrometry.

    Science.gov (United States)

    Lee, Jihyeon; Park, Sehwan; Cho, Soo Gyeong; Goh, Eun Mee; Lee, Sungman; Koh, Sung-Suk; Kim, Jeongkwon

    2014-03-01

    Corona discharge ionization combined with ion mobility spectrometry-mass spectrometry (IMS-MS) was utilized to investigate five common explosives: cyclonite (RDX), trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), cyclotetramethylenetetranitramine (HMX), and 2,4-dinitrotoluene (DNT). The MS scan and the selected ion IMS analyses confirmed the identities of the existing ion species and their drift times. The ions observed were RDX·NO3(-), TNT(-), PETN·NO3(-), HMX·NO3(-), and DNT(-), with average drift times of 6.93 ms, 10.20 ms, 9.15 ms, 12.24 ms, 11.30 ms, and 8.89 ms, respectively. The reduced ion mobility values, determined from a standard curve calculated by linear regression of (normalized drift times)(-1) versus literature K0 values, were 2.09, 1.38, 1.55, 1.15, 1.25, and 1.60 cm(2) V(-1) s(-1), respectively. The detection limits were found to be 0.1 ng for RDX, 10 ng for TNT, 0.5 ng for PETN, 5.0 ng for HMX, and 10 ng for DNT. Simplified chromatograms were observed when nitrogen, as opposed to air, was used as the drift gas, but the detection limits were approximately 10 times worse (i.e., less sensitivity of detection). PMID:24468343

  11. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 1. Peptides to Proteins

    Science.gov (United States)

    Donohoe, Gregory C.; Khakinejad, Mahdiar; Valentine, Stephen J.

    2015-04-01

    Ion mobility spectrometry (IMS) coupled with hydrogen deuterium exchange (HDX)-mass spectrometry (MS) has been used to study the conformations of negatively-charged peptide and protein ions. Results are presented for ion conformers of angiotensin 1, a synthetic peptide (SP), bovine insulin, ubiquitin, and equine cytochrome c. In general, the SP ion conformers demonstrate a greater level of HDX efficiency as a greater proportion of the sites undergo HDX. Additionally, these ions exhibit the fastest rates of exchange. Comparatively, the angiotensin 1 ions exhibit a lower rate of exchange and HDX level presumably because of decreased accessibility of exchange sites by charge sites. The latter are likely confined to the peptide termini. Insulin ions show dramatically reduced HDX levels and exchange rates, which can be attributed to decreased conformational flexibility resulting from the disulfide bonds. For the larger ubiquitin and protein ions, increased HDX is observed for larger ions of higher charge state. For ubiquitin, a conformational transition from compact to more elongated species (from lower to higher charge states) is reflected by an increase in HDX levels. These results can be explained by a combination of interior site protection by compact conformers as well as decreased access by charge sites. The elongated cytochrome c ions provide the largest HDX levels where higher values correlate with charge state. These results are consistent with increased exchange site accessibility by additional charge sites. The data from these enhanced IMS-HDX experiments are described in terms of charge site location, conformer rigidity, and interior site protection.

  12. Progress Toward a Global, EOS-Era Aerosol Air Mass Type Climatology

    Science.gov (United States)

    Kahn, Ralph A.

    2012-01-01

    The MISR and MODIS instruments aboard the NASA Earth Observing System's Terra Satellite have been collecting data containing information about the state of Earth's atmosphere and surface for over eleven years. Data from these instruments have been used to develop a global, monthly climatology of aerosol amount that is widely used as a constraint on climate models, including those used for the 2007 IPCC assessment report. The next frontier in assessing aerosol radiative forcing of climate is aerosol type, and in particular, the absorption properties of major aerosol air masses. This presentation will focus on the prospects for constraining aerosol type globally, and the steps we are taking to apply a combination of satellite and suborbital data to this challenge.

  13. OMI tropospheric NO2 air mass factors over South America: effects of biomass burning aerosols

    Directory of Open Access Journals (Sweden)

    P. Castellanos

    2015-03-01

    Full Text Available Biomass burning is an important and uncertain source of aerosols and NOx (NO + NO2 to the atmosphere. OMI observations of tropospheric NO2 are essential for characterizing this emissions source, but inaccuracies in the retrieval of NO2 tropospheric columns due to the radiative effects of aerosols, especially light-absorbing carbonaceous aerosols, are not well understood. It has been shown that the O2–O2 effective cloud fraction and pressure retrieval is sensitive to aerosol optical and physical properties, including aerosol optical depth (AOD. Aerosols implicitly influence the tropospheric air mass factor (AMF calculations used in the NO2 retrieval through the effective cloud parameters used in the independent pixel approximation. In this work, we explicitly account for the effects of biomass burning aerosols in the tropospheric NO2 AMF calculation by including collocated aerosol extinction vertical profile observations from the CALIOP instrument, and aerosol optical depth (AOD and single scattering albedo (SSA retrieved by the OMI near-UV aerosol algorithm (OMAERUV in the DISAMAR radiative transfer model for cloud-free scenes. Tropospheric AMFs calculated with DISAMAR were benchmarked against AMFs reported in the Dutch OMI NO2 (DOMINO retrieval; the mean and standard deviation (SD of the difference was 0.6 ± 8%. Averaged over three successive South American biomass burning seasons (2006–2008, the spatial correlation in the 500 nm AOD retrieved by OMI and the 532 nm AOD retrieved by CALIOP was 0.6, and 72% of the daily OMAERUV AOD observations were within 0.3 of the CALIOP observations. Overall, tropospheric AMFs calculated with observed aerosol parameters were on average 10% higher than AMFs calculated with effective cloud parameters. For effective cloud radiance fractions less than 30%, or effective cloud pressures greater than 800 hPa, the difference between tropospheric AMFs based on implicit and explicit aerosol parameters is on

  14. Focus on Advancing High Performance Mass Spectrometry, Honoring Dr. Richard D. Smith, Recipient of the 2013 Award for a Distinguished Contribution in Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Erin Shammel [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Muddiman, David C. [North Carolina State Univ., Raleigh, NC (United States); Loo, Joseph [Univ. of California, Los Angeles, CA (United States)

    2014-10-18

    This special focus issue of the Journal of the American Society for Mass Spectrometry celebrates the accomplishments of Dr. Richard D. Smith, the recipient of the 2013ASMS Award for a Distinguished Contribution in Mass Spectrometry, and who serves as a Battelle Fellow, Chief Scientist in the Biological Sciences Division, and Director of Proteomics Research at Pacific Northwest National Laboratory (PNNL) in Richland, WA. The award is for his development of the electrodynamic ion funnel.

  15. Identification of aerosol types over an urban site based on air-mass trajectory classification

    Science.gov (United States)

    Pawar, G. V.; Devara, P. C. S.; Aher, G. R.

    2015-10-01

    Columnar aerosol properties retrieved from MICROTOPS II Sun Photometer measurements during 2010-2013 over Pune (18°32‧N; 73°49‧E, 559 m amsl), a tropical urban station in India, are analyzed to identify aerosol types in the atmospheric column. Identification/classification is carried out on the basis of dominant airflow patterns, and the method of discrimination of aerosol types on the basis of relation between aerosol optical depth (AOD500 nm) and Ångström exponent (AE, α). Five potential advection pathways viz., NW/N, SW/S, N, SE/E and L have been identified over the observing site by employing the NOAA-HYSPLIT air mass back trajectory analysis. Based on AE against AOD500 nm scatter plot and advection pathways followed five major aerosol types viz., continental average (CA), marine continental average (MCA), urban/industrial and biomass burning (UB), desert dust (DD) and indeterminate or mixed type (MT) have been identified. In winter, sector SE/E, a representative of air masses traversed over Bay of Bengal and Eastern continental Indian region has relatively small AOD (τpλ = 0.43 ± 0.13) and high AE (α = 1.19 ± 0.15). These values imply the presence of accumulation/sub-micron size anthropogenic aerosols. During pre-monsoon, aerosols from the NW/N sector have high AOD (τpλ = 0.61 ± 0.21), and low AE (α = 0.54 ± 0.14) indicating an increase in the loading of coarse-mode particles over Pune. Dominance of UB type in winter season for all the years (i.e. 2010-2013) may be attributed to both local/transported aerosols. During pre-monsoon seasons, MT is the dominant aerosol type followed by UB and DD, while the background aerosols are insignificant.

  16. Systematization of the mass spectra for speciation of inorganic salts with static secondary ion mass spectrometry.

    Science.gov (United States)

    Van Ham, Rita; Van Vaeck, Luc; Adams, Freddy C; Adriaens, Annemie

    2004-05-01

    The analytical use of mass spectra from static secondary ion mass spectrometry for the molecular identification of inorganic analytes in real life surface layers and microobjects requires an empirical insight in the signals to be expected from a given compound. A comprehensive database comprising over 50 salts has been assembled to complement prior data on oxides. The present study allows the systematic trends in the relationship between the detected signals and molecular composition of the analyte to be delineated. The mass spectra provide diagnostic information by means of atomic ions, structural fragments, molecular ions, and adduct ions of the analyte neutrals. The prediction of mass spectra from a given analyte must account for the charge state of the ions in the salt, the formation of oxide-type neutrals from oxy salts, and the occurrence of oxidation-reduction processes.

  17. The 50th ASMS Conference on Mass Spectrometry and Allied Topics

    OpenAIRE

    Brancia, Francesco L.

    2002-01-01

    Development of new mass spectrometers and implementation of new analytical methods were the central themes of the conference. The majority of oral presentations and posters were concerned with the application of mass spectrometry to pharmaceutical and biotechnological research.

  18. Fast airborne aerosol size and chemistry measurements with the high resolution aerosol mass spectrometer during the MILAGRO Campaign

    Directory of Open Access Journals (Sweden)

    P. F. DeCarlo

    2007-12-01

    Full Text Available The concentration, size, and composition of non-refractory submicron aerosol (NR-PM1 was measured over Mexico City and central Mexico with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS onboard the NSF/NCAR C-130 aircraft as part of the MILAGRO field campaign. This was the first aircraft deployment of the HR-ToF-AMS, in which the instrument performed very well, and provided 12 s data. The aerosol mass from the AMS correlates strongly with other aerosol measurements on board the aircraft. Organic aerosol (OA species dominate the NR-PM1 mass. OA correlates strongly with CO and HCN indicating that pollution (mostly secondary OA, SOA and biomass burning (BB are the main OA sources. The OA to CO ratio indicates a typical value for aged air of around 80 μg m−3 (STP ppm−1. This is within the range observed in outflow from the Northeastern US, which could be due to a compensating effect between higher BB but lower biogenic VOC emissions during this study. The O/C atomic ratio for OA is calculated from the HR mass spectra and shows a clear increase with photochemical age, as SOA forms rapidly and quickly overwhelms primary urban OA, consistent with Volkamer et al. (2006 and Kleinman et al. (2007b. BB OA is marked by signals at m/z 60 and 73, and also by a signal enhancement at large m/z indicative of larger molecules or more resistance to fragmentation. The main inorganic components show different spatial patterns and size distributions. Sulfate is regional in nature with clear volcanic and petrochemical/power plant sources, while the urban area is not a major source for this species. Nitrate is enhanced significantly in the urban area and immediate outflow, and is strongly correlated with CO indicating a strong urban source. The importance of nitrate decreases with distance from the city likely due to evaporation. BB does not appear to be a strong source of nitrate

  19. Fast Airborne Aerosol Size and Chemistry Measurements with the High Resolution Aerosol Mass Spectrometer during the MILAGRO Campaign

    Science.gov (United States)

    DeCarlo, P. F.; Dunlea, E. J.; Kimmel, J. R.; Aiken, A. C.; Sueper, D.; Crounse, J.; Wennberg, P. O.; Emmons, L.; Shinozuka, Y.; Clarke, A.; Zhou, J.; Tomlinson, J.; Collins,D. R.; Knapp, D.; Weinheimer, A. J.; Montzka,D. D.; Campos,T.; Jimenez, J. L.

    2007-01-01

    The concentration, size, and composition of non-refractory submicron aerosol (NR-PM(sub l)) was measured over Mexico City and central Mexico with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) onboard the NSF/NCAR C-130 aircraft as part of the MILAGRO field campaign. This was the first aircraft deployment of the HR-ToF-AMS. During the campaign the instrument performed very well, and provided 12 s data. The aerosol mass from the AMS correlates strongly with other aerosol measurements on board the aircraft. Organic aerosol (OA) species dominate the NR-PM(sub l) mass. OA correlates strongly with CO and HCN indicating that pollution (mostly secondary OA, SOA) and biomass burning (BB) are the main OA sources. The OA to CO ratio indicates a typical value for aged air of around 80 microg/cubic m (STP) ppm(exp -1). This is within the range observed in outflow from the Northeastern US, which could be due to a compensating effect between higher BB but lower biogenic VOC emissions during this study. The O/C atomic ratio for OA is calculated from the HR mass spectra and shows a clear increase with photochemical age, as SOA forms rapidly and quickly overwhelms primary urban OA, consistent with Volkamer et al. (2006) and Kleinman et al. (2008). The stability of the OA/CO while O/C increases with photochemical age implies a net loss of carbon from the OA. BB OA is marked by signals at m/z 60 and 73, and also by a signal enhancement at large m/z indicative of larger molecules or more resistance to fragmentation. The main inorganic components show different spatial patterns and size distributions. Sulfate is regional in nature with clear volcanic and petrochemical/power plant sources, while the urban area is not a major regional source for this species. Nitrate is enhanced significantly in the urban area and immediate outflow, and is strongly correlated with CO indicating a strong urban source. The importance of nitrate decreases with distance from the city

  20. Aqueous phase oligomerization of α,β-unsaturated carbonyls and acids investigated using ion mobility spectrometry coupled to mass spectrometry (IMS-MS)

    Science.gov (United States)

    Renard, Pascal; Tlili, Sabrine; Ravier, Sylvain; Quivet, Etienne; Monod, Anne

    2016-04-01

    One of the current essential issues to unravel our ability to forecast future climate change and air quality, implies a better understanding of natural processes leading to secondary organic aerosol (SOA) formation, and in particular the formation and fate of oligomers. The difficulty in characterizing macromolecules is to discern between large oxygenated molecules from series of oligomers containing repeated small monomers of diverse structures. In the present study, taking advantage from previously established radical vinyl oligomerization of methyl vinylketone (MVK) in the aqueous phase, where relatively simple oligomers containing up to 14 monomers were observed, we have investigated the same reactivity on several other unsaturated water soluble organic compounds (UWSOCs) and on a few mixtures of these precursor compounds. The technique used to characterize the formed oligomers was a traveling wave ion mobility spectrometry coupled to a hybrid quadrupole - time of flight mass spectrometer (IMS-MS) fitted with an electrospray source and ultra-high performance liquid chromatography (UPLC). The technique allows for an additional separation, especially for large ions, containing long carbon chains. We have shown the efficiency of the IMS-mass spectrometry technique to detect oligomers derived from MVK photooxidation in the aqueous phase. The results were then compared to other oligomers, derived from ten other individual biogenic UWSOCs. The technique allowed distinguishing between different oligomers arising from different precursors. It also clearly showed that compounds bearing a non-conjugated unsaturation did not provide oligomerization. Finally, it was shown that the IMS-mass spectrometry technique, applied to mixtures of unsaturated conjugated precursors, exhibited the ability of these precursors to co-oligomerize, i.e. forming only one complex oligomer system bearing monomers of different structures. The results are discussed in terms of atmospheric