An intercomparison study of four different techniques for measuring the chemical composition of nanoparticles
- 1Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, Frankfurt am Main, 60438, Germany
- 2Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
- 3Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- 4Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- 5TOFWERK AG, Thun, 3600, Switzerland
- 6Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
- 7Atmospheric Chemistry Department, Max Planck Institute for Chemistry, 55128 Mainz, Germany
- 8CENTRA and Faculdade de Ciências da Universidade de Lisboa, Campo Grande 1749–016, Lisboa, Portugal
- 9Institute for Atmospheric and Earth System Research (INAR) / Physics, Faculty of Science, University of Helsinki, 00014 Helsinki, Finland
- 10Helsinki Institute of Physics, University of Helsinki, 00014 Helsinki, Finland
- 11Department of Chemistry & CIRES, University of Colorado Boulder, Boulder, CO, 80309-0215, USA
- 12Lebedev Physical Institute, Russian Academy of Sciences, 119991, Moscow, Russia
- 13Moscow Institute of Physics and Technology, Moscow, 117303, Russia
- 14CERN, 1211 Geneva, Switzerland
- 15Department of Atmospheric and Oceanic Sciences, University of Colorado Boulder, Boulder, CO 80309, USA
- 16Institute for Ion and Applied Physics, University of Innsbruck, 6020 Innsbruck, Austria
- 17Finnish Meteorological Institute, 00560 Helsinki, Finland
- 18Faculty of Physics, University of Vienna, 1090 Vienna, Austria
- 19Beijing Weather Modification Office, China
- 20IDL, Universidade da Beira Interior, R. Marquês de Ávila e Bolama, Covilhã, 6201-001, Portugal
- 21Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany
- 22Ionicon Analytik GmbH, 6020 Innsbruck, Austria
- 23Aerosol and Haze Laboratory, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, P.R. China
- 24Aerodyne Research, Billerica, MA 01821 USA
Abstract. Currently, the complete chemical characterization of nanoparticles (<100 nm) represents an analytical challenge, since these particles are abundant in number but have negligible mass. Several methods for particle-phase characterization have been recently developed to better detect and infer more accurately the sources and fates of ultra-fine particles, but a detailed comparison of different approaches is missing. Here we report on the chemical composition of secondary organic aerosol (SOA) nanoparticles from experimental studies of α-pinene ozonolysis at -50 ºC, -30 ºC, and -10 ºC, and inter-compare the results measured by different techniques. The experiments were performed at the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber at the European Organization for Nuclear Research (CERN). The chemical composition was measured simultaneously by four different techniques: 1) Thermal Desorption-Differential Mobility Analyzer (TD-DMA) coupled to a NO3- chemical ionization-atmospheric-pressure-interface-time-of-flight (CI-APi-TOF) mass spectrometer, 2) Filter Inlet for Gases and AEROsols (FIGAERO) coupled to an I- high-resolution time-of-flight chemical-ionization mass spectrometer (HRToF-CIMS), 3) Extractive Electrospray Na+ Ionization time-of-flight mass spectrometer (EESI-TOF), and 4) Offline analysis of filters (FILTER) using Ultra-high-performance liquid chromatography (UHPLC) and heated electrospray ionization (HESI) coupled to an Orbitrap high-resolution mass spectrometer (HRMS). Intercomparison was performed by contrasting the observed chemical composition as a function of oxidation state and carbon number, by calculating the volatility and comparing the fraction of volatility classes, and by comparing the thermal desorption behavior (for the thermal desorption techniques: TD-DMA and FIGAERO) and performing positive matrix factorization (PMF) analysis for the thermograms. We found that the methods generally agree on the most important compounds that are found in the nanoparticles. However, they do see different parts of the organic spectrum. We suggest potential explanations for these differences: thermal decomposition, aging, sampling artifacts, etc. We applied PMF analysis and found insights of thermal decomposition in the TD-DMA and the FIGAERO.
Lucía Caudillo et al.
Lucía Caudillo et al.
Lucía Caudillo et al.
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