scholarly journals FATES: a flexible analysis toolkit for the exploration of single-particle mass spectrometer data

2017 ◽  
Vol 10 (4) ◽  
pp. 1323-1334 ◽  
Author(s):  
Camille M. Sultana ◽  
Gavin C. Cornwell ◽  
Paul Rodriguez ◽  
Kimberly A. Prather
Keyword(s):  
Mass Spectrometer ◽  
User Interfaces ◽  
Single Particle ◽  
Spectral Characteristics ◽  
Large Data ◽  
Particle Mass ◽  
Data Sets ◽  
Mass Spectral ◽  
Data Formats ◽  
Spectrometer Data

Abstract. Single-particle mass spectrometer (SPMS) analysis of aerosols has become increasingly popular since its invention in the 1990s. Today many iterations of commercial and lab-built SPMSs are in use worldwide. However, supporting analysis toolkits for these powerful instruments are outdated, have limited functionality, or are versions that are not available to the scientific community at large. In an effort to advance this field and allow better communication and collaboration between scientists, we have developed FATES (Flexible Analysis Toolkit for the Exploration of SPMS data), a MATLAB toolkit easily extensible to an array of SPMS designs and data formats. FATES was developed to minimize the computational demands of working with large data sets while still allowing easy maintenance, modification, and utilization by novice programmers. FATES permits scientists to explore, without constraint, complex SPMS data with simple scripts in a language popular for scientific numerical analysis. In addition FATES contains an array of data visualization graphic user interfaces (GUIs) which can aid both novice and expert users in calibration of raw data; exploration of the dependence of mass spectral characteristics on size, time, and peak intensity; and investigations of clustered data sets.

scholarly journals FATES: A Flexible Analysis Toolkit for the Exploration of Single Particle Mass Spectrometer Data

2016 ◽  
Author(s):  
Camille M. Sultana ◽  
Gavin Cornwell ◽  
Paul Rodriguez ◽  
Kimberly A. Prather
Keyword(s):  
Mass Spectrometer ◽  
Single Particle ◽  
Mass Spectra ◽  
Large Datasets ◽  
Particle Mass ◽  
Data Exploration ◽  
Data Sets ◽  
Data Formats ◽  
Peak Intensity ◽  
Spectrometer Data

Abstract. Single particle mass spectrometer (SPMS) analysis of aerosols has become increasingly popular since its invention in the 1990s. Today many iterations of commercial and lab-built SPMS are in use worldwide. However supporting analysis toolkits for these powerful instruments are either outdated, have limited functionality, or are versions that are not available to the scientific community at large. In an effort to advance this field and allow better communication and collaboration between scientists we have developed FATES (Flexible Analysis Toolkit for the Exploration of SPMS data), a MATLAB toolkit easily extensible to an array of SPMS designs and data formats. FATES was developed to minimize the computational demands of working with large datasets while still allowing easy maintenance, modification, and utilization by novice programmers. FATES permits scientists to explore, without constraint, complex SPMS data with simple scripts in a language popular for scientific numerical analysis. In addition FATES contains an array of data visualization GUIs which can aid both novice and expert users in calibration of raw data, exploration of the dependence of mass spectra characteristics on size, time, and peak intensity, as well investigations of clustered data sets.

scholarly journals Sources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris

2012 ◽  
Vol 12 (4) ◽  
pp. 1681-1700 ◽  
Author(s):  
R. M. Healy ◽  
J. Sciare ◽  
L. Poulain ◽  
K. Kamili ◽  
M. Merkel ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Biomass Burning ◽  
Single Particle ◽  
Mass Concentration ◽  
Elemental Carbon ◽  
Fossil Fuel ◽  
Time Of Flight ◽  
Particle Mass ◽  
Mass Size ◽  
Mass Concentrations

Abstract. An Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS) was deployed to investigate the size-resolved chemical composition of single particles at an urban background site in Paris, France, as part of the MEGAPOLI winter campaign in January/February 2010. ATOFMS particle counts were scaled to match coincident Twin Differential Mobility Particle Sizer (TDMPS) data in order to generate hourly size-resolved mass concentrations for the single particle classes observed. The total scaled ATOFMS particle mass concentration in the size range 150–1067 nm was found to agree very well with the sum of concurrent High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and Multi-Angle Absorption Photometer (MAAP) mass concentration measurements of organic carbon (OC), inorganic ions and black carbon (BC) (R2 = 0.91). Clustering analysis of the ATOFMS single particle mass spectra allowed the separation of elemental carbon (EC) particles into four classes: (i) EC attributed to biomass burning (ECbiomass), (ii) EC attributed to traffic (ECtraffic), (iii) EC internally mixed with OC and ammonium sulfate (ECOCSOx), and (iv) EC internally mixed with OC and ammonium nitrate (ECOCNOx). Average hourly mass concentrations for EC-containing particles detected by the ATOFMS were found to agree reasonably well with semi-continuous quantitative thermal/optical EC and optical BC measurements (r2 = 0.61 and 0.65–0.68 respectively, n = 552). The EC particle mass assigned to fossil fuel and biomass burning sources also agreed reasonably well with BC mass fractions assigned to the same sources using seven-wavelength aethalometer data (r2 = 0.60 and 0.48, respectively, n = 568). Agreement between the ATOFMS and other instrumentation improved noticeably when a period influenced by significantly aged, internally mixed EC particles was removed from the intercomparison. 88% and 12% of EC particle mass was apportioned to fossil fuel and biomass burning respectively using the ATOFMS data compared with 85% and 15% respectively for BC estimated from the aethalometer model. On average, the mass size distribution for EC particles is bimodal; the smaller mode is attributed to locally emitted, mostly externally mixed EC particles, while the larger mode is dominated by aged, internally mixed ECOCNOx particles associated with continental transport events. Periods of continental influence were identified using the Lagrangian Particle Dispersion Model (LPDM) "FLEXPART". A consistent minimum between the two EC mass size modes was observed at approximately 400 nm for the measurement period. EC particles below this size are attributed to local emissions using chemical mixing state information and contribute 79% of the scaled ATOFMS EC particle mass, while particles above this size are attributed to continental transport events and contribute 21% of the EC particle mass. These results clearly demonstrate the potential benefit of monitoring size-resolved mass concentrations for the separation of local and continental EC emissions. Knowledge of the relative input of these emissions is essential for assessing the effectiveness of local abatement strategies.

scholarly journals Single-particle measurements of bouncing particles and in situ collection efficiency from an airborne aerosol mass spectrometer (AMS) with light-scattering detection

2017 ◽  
Vol 10 (10) ◽  
pp. 3801-3820 ◽  
Author(s):  
Jin Liao ◽  
Charles A. Brock ◽  
Daniel M. Murphy ◽  
Donna T. Sueper ◽  
André Welti ◽  
...  
Keyword(s):  
Light Scattering ◽  
Mass Spectrometer ◽  
Single Particle ◽  
Total Mass ◽  
Mass Spectra ◽  
Collection Efficiency ◽  
Aerosol Mass Spectrometer ◽  
Mass Spectral ◽  
Aerosol Mass ◽  
Spectral Signal

Abstract. A light-scattering module was coupled to an airborne, compact time-of-flight aerosol mass spectrometer (LS-AMS) to investigate collection efficiency (CE) while obtaining nonrefractory aerosol chemical composition measurements during the Southeast Nexus (SENEX) campaign. In this instrument, particles scatter light from an internal laser beam and trigger saving individual particle mass spectra. Nearly all of the single-particle data with mass spectra that were triggered by scattered light signals were from particles larger than ∼ 280 nm in vacuum aerodynamic diameter. Over 33 000 particles are characterized as either prompt (27 %), delayed (15 %), or null (58 %), according to the time and intensity of their total mass spectral signals. The particle mass from single-particle spectra is proportional to that derived from the light-scattering diameter (dva-LS) but not to that from the particle time-of-flight (PToF) diameter (dva-MS) from the time of the maximum mass spectral signal. The total mass spectral signal from delayed particles was about 80 % of that from prompt ones for the same dva-LS. Both field and laboratory data indicate that the relative intensities of various ions in the prompt spectra show more fragmentation compared to the delayed spectra. The particles with a delayed mass spectral signal likely bounced off the vaporizer and vaporized later on another surface within the confines of the ionization source. Because delayed particles are detected by the mass spectrometer later than expected from their dva-LS size, they can affect the interpretation of particle size (PToF) mass distributions, especially at larger sizes. The CE, measured by the average number or mass fractions of particles optically detected that had measurable mass spectra, varied significantly (0.2–0.9) in different air masses. The measured CE agreed well with a previous parameterization when CE > 0.5 for acidic particles but was sometimes lower than the minimum parameterized CE of 0.5.

scholarly journals Quantitative single particle analysis with the Aerodyne aerosol mass spectrometer: development of a new classification algorithm and its application to field data

2013 ◽  
Vol 6 (3) ◽  
pp. 5653-5691 ◽  
Author(s):  
F. Freutel ◽  
F. Drewnick ◽  
J. Schneider ◽  
T. Klimach ◽  
S. Borrmann
Keyword(s):  
Mass Spectrometer ◽  
Single Particle ◽  
Field Data ◽  
Classification Algorithm ◽  
Particle Mass ◽  
Submicron Particles ◽  
Particle Analysis ◽  
Mixing State ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass

Abstract. Single particle mass spectrometry has proven a valuable tool for gaining information on the mixing state of aerosol particles. With the Aerodyne aerosol mass spectrometer (AMS) equipped with a light scattering probe, non-refractory components of submicron particles with diameters larger than about 300 nm can even be quantified on a single particle basis. Here, we present a new method for the analysis of AMS single particle mass spectra. The developed algorithm classifies the particles according to their components (e.g., sulphate, nitrate, different types of organics) and simultaneously provides quantitative information about the composition of the single particles. This classification algorithm was validated by applying it to data acquired in laboratory experiments with particles of known composition, and applied to field data acquired during the MEGAPOLI summer campaign (July 2009) in Paris. As shown, it is not only possible to directly measure the mixing state of atmospheric particles, but also to directly observe repartitioning of semi-volatile species between gas and particle phase during the course of the day.

scholarly journals Exploring femtosecond laser ablation in single particle aerosol mass spectrometry

2017 ◽  
Author(s):  
Ramakrishna Ramisetty ◽  
Ahmed Abdelmonem ◽  
Xiaoli Shen ◽  
Harald Saathoff ◽  
Thomas Leisner ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Laser Ablation ◽  
Power Density ◽  
Single Particle ◽  
Pulse Energy ◽  
Particle Mass ◽  
Fragmentation Pattern ◽  
Mass Spectral ◽  
Custom Made ◽  
Fs Laser

Abstract. Size, composition, and mixing state of individual aerosol particles can be analysed in real time using single particle mass spectrometry (SPMS). In SPMS, laser ablation is the most widely used method for desorption and ionization of particle components, often realizing both in one single step. Excimer lasers are well suited for this task due to their relatively high power density (107 W cm−2–1010 W cm−2) in nanosecond (ns) pulses at ultraviolet (UV) wavelengths, and short triggering times. However, varying particle optical properties and matrix effects make a quantitative interpretation of this analytical approach challenging. In atmospheric SPMS applications, this influences both the mass fraction of an individual particle that gets ablated, as well as the resulting mass spectral fragmentation pattern of the ablated material. The goal of the present study is to explore the use of shorter (femtosecond, fs) laser pulses for atmospheric SPMS, and to systematically investigate the influence of power density and pulse duration on airborne particle (polystyrene latex, SiO2, NH4NO3, NaCl, and custom-made core-shell particles) ablation and reproducibility of mass spectral signatures. We used a laser ablation aerosol time-of-flight single particle mass spectrometer (LAAPTOF, AeroMegt GmbH), originally equipped with an excimer laser (wavelength 193 nm, pulse width 8 ns, pulse energy 4 mJ), and coupled it to an fs-laser (Spectra Physics Solstice-100F ultrafast laser) with similar pulse energy, but longer wavelengths (266 nm with 100 fs and 0.2 mJ, 800 nm with 100 fs and 4 mJ, respectively). Generally, mass spectra exhibit an increase in ion intensities (factor 1 to 5) with increasing laser power density (~ 108 W cm−2 to ~ 1013 W cm−2) from ns- to fs-laser. At the same time, fs-laser ablation produces spectra with larger ion fragments and ion clusters, as well as clusters with oxygen, which does not render spectra interpretation more simple compared to ns-laser ablation. Quantification of ablated material remains difficult due to incomplete ionization of the particle. Furthermore, the fs-laser application still suffers from limitations in triggering it in a useful timeframe. Further tests are needed to test potential advantages of fs- over ns-laser ablation in atmospheric SPMS.

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