AMS Spectra Intercomp

Shortcut to this page is: http://tinyurl.com/AMScomp

The purpose of this page is to serve as a repository of information for the AMS spectral intercomparison experiment. This follows up on discussions at the 10th AMS Users Meeting in Toronto, Canada. The objective is to evaluate the variability of the spectra from different AMSs (including Q-AMS, C-ToF-AMS, HR-ToF-AMS in V and W modes, and mini-AMS) for several standard species.

Tentative List of Molecules

• We plan to choose 5 from the following list (plus any other suggestions):
  • Ammonium nitrate
  • Ammonium sulfate
  • Squalene (liquid HOA surrogate) (generated by evaporation-condensation)
  • Pyrene (PAH, little fragmentation and tendency for multiple charging) (generated by evaporation-condensation)
  • DOS (generated by evaporation-condensation)
  • a perfluoroalkane (generated by evaporation-condensation)
  • Mannitol (bioaerosol marker) (atomized in water)
  • Levoglucosan, BBOA marker (atomized in water)
  • Azelaic acid (largest differences between instruments according to the Manchester group -- but harder to nebulize (PW))
  • Succinic acid (OOA surrogate) (atomized in water)
  • Fulvic Acid (OOA surrogate) (atomized in water)

• People's opinions on what to measure:
  • A K-S: no strong opinions, but would lean to use: Ammonium nitrate, Squalene, Pyrene, Levoglucosan, Succinic acid
  • Leaitch Group: can only use species generated by atomizing in water, would like to suggest ammonium sulfate and mannitol as well.

Confirmed Participants

• Claudia Mohr & Maarten Heringa (PSI): HR-ToF
• Person TBD, Galway: HR-ToF
• Jay Slowik (Univ. of Toronto): C-ToF
• Laurent Poulain (IfT, Leipzig, Germany): HR-ToF
• Ann Middlebrook, C-ToF
• John Shilling (PNNL): C-ToF or HR-ToF depending on timing
• Rami Alfarra & Paul Williams, Univ. of Manchester, UK: 1 HR-ToF, 1 C-ToF
• Taehyoung Lee (Colorado State Univ.): HR-ToF
• Yin-Nan Lee (Brookhaven National Laboratory):
• Gavin Phillips (Centre for Ecology and Hydrology): 1 HR-Tof_AMS, 1 Q-AMS
• Doug Day (Russell Group, Scripps Institution of Oceanography): 1 HR-ToF
• Puneet Chhabra (California Institute of Technology):
• Astrid Kiendler-Scharr, Juelich FZ: 1 Q-AMS, 1 HR-ToF
• Leah Williams (Aerodyne): Q-AMS, C-ToF-AMS, HR-ToF-AMS
• Johannes Schneider (Max Planck): C-ToF
• Frank Drewnick (Max Planck): HR-ToF
• Jimenez Group, Univ. of Colorado-Boulder: 2 HR-ToF, 1 C-ToF, 1 Q-AMS
• Qi Zhang, UC-Davis: 1 HR-ToF
• Akinori Takami, (NIES, Japan): HR-ToF-AMS, Q-AMS, and Mini-AMS.
• Steven Howell, (University of Hawaii): HR-ToF-AMS
• Samara Carbone and Hikka Timonen, (Finnish Meteorological Institute): HR-ToF-AMS
• Lea Hildebrandt, (Carnegie Mellon University): Q-AMS, HR-AMS
• Desiree Toom-Sauntry (Environment Canada): mini-AMS, C-ToF

Practical Details

• Michael Lechner (mlecnher2 at gmail.com) in the Jimenez group will coordinate sending the samples and receiving the spectra

• Importantly, we need a standard method of preparation. We have made suggestions above but welcome comments.

• Calibrate vaporizer temperature with Leah's procedure

• We will send small glass vials with small quantities of all the standards to all participating groups. It is important that the species come from the same sample, as impurities vary depending on the supplier and even between batches of the same supplier.

• We show how to order NERL water to all groups to make sure that we don't have different impurities in the atomization water

• Atomizers should be rinsed with DI water twice between compounds.

• Do we do something similar with solvents?

• People run all the standards on all of their AMSs, and upload spectra (ITX) and PXP to an SFTP site (along with vaporizer displayed T, V, A)

• Data should be recorded in MS and PToF modes, with a standard timing between modes (to be specified). We may also want to look at the closed spectra.

• Donna will implement a button in Squirrel and Pika to export the spectra in an standard format to reduce data analysis and intercomparison chores.

• We will discuss the comparison of the spectra in the next Clinic or Users Meeting, depending on how quickly we make progress.