title: Field-deployable, high-resolution, time-of-flight aerosol mass spectrometer.
abstract: The development of a new high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is reported. The high-resolution capabilities of this instrument allow the direct separation of most ions from inorganic and organic species at the same nominal m/z, the quantification of several types of organic fragments (CxHy, CxHyOz, CxHyNp, CxHyOzNp), and the direct identification of organic nitrogen and organosulfur content. This real-time instrument is field-deployable, and its high time resolution (0.5 Hz has been demonstrated) makes it well-suited for studies in which time resolution is critical, such as aircraft studies. The instrument has two ion optical modes: a single-reflection configuration offers higher sensitivity and lower resolving power (up to approximately 2100 at m/z 200), and a two-reflectron configuration yields higher resolving power (up to approximately 4300 at m/z 200) with lower sensitivity. The instrument also allows the determination of the size distributions of all ions. One-minute detection limits for submicrometer aerosol are <0.04 microg m(-3) for all species in the high-sensitivity mode and <0.4 microg m(-3) in the high-resolution mode. Examples of ambient aerosol data are presented from the SOAR-1 study in Riverside, CA, in which the spectra of ambient organic species are dominated by CxHy and CxHyOz fragments, and different organic and inorganic fragments at the same nominal m/z show different size distributions. Data are also presented from the MIRAGE C-130 aircraft study near Mexico City, showing high correlation with independent measurements of surrogate aerosol mass concentration.
authors.affiliation: Cooperative Institute for Research in the Environmental Sciences (CIRES), University of Colorado, Boulder, Colorado 80309-0216, USA.
authors.forename: Peter F
authors.initials: PF
authors.lastname: DeCarlo
authors.forename: Joel R
authors.initials: JR
authors.lastname: Kimmel
authors.forename: Achim
authors.initials: A
authors.lastname: Trimborn
authors.forename: Megan J
authors.initials: MJ
authors.lastname: Northway
authors.forename: John T
authors.initials: JT
authors.lastname: Jayne
authors.forename: Allison C
authors.initials: AC
authors.lastname: Aiken
authors.forename: Marc
authors.initials: M
authors.lastname: Gonin
authors.forename: Katrin
authors.initials: K
authors.lastname: Fuhrer
authors.forename: Thomas
authors.initials: T
authors.lastname: Horvath
authors.forename: Kenneth S
authors.initials: KS
authors.lastname: Docherty
authors.forename: Doug R
authors.initials: DR
authors.lastname: Worsnop
authors.forename: Jose L
authors.initials: JL
authors.lastname: Jimenez