1 / 6

Thermal decomposition

Thermal decomposition. Pump electronics. ionization and reaction. HV electronics. Calibration Box. detection. New PAN instrument:. Chemical Ionization Mass Spectrometer based on Reaction of radicals with I - Fast Sensitive Selective Autonomous Slusher et al., JGR 2004.

zach
Download Presentation

Thermal decomposition

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Thermal decomposition Pump electronics ionization and reaction HV electronics Calibration Box detection

  2. New PAN instrument: • Chemical Ionization Mass Spectrometer • based on Reaction of radicals with I- • Fast • Sensitive • Selective • Autonomous • Slusher et al., JGR 2004

  3. I- Chemistry • I- reacts with N2O5 and ClNO3 • k = 1 x 10-9 • product NO3- • I- unreactive with PAN, HNO3, HCl, SO2, O3, H2O, etc. • Forms weak clusters with H2O, etc.

  4. I- reactions with RO2 • I- + RO2 → RO- + IO • R = CF3, CH3C(O), CH3CH2C(O), etc. • i.e. RO- must be conjugated base of strong acid such as acetic acid • used by Howard, Villalta, Froyd, deGouw, etc. to study kinetics of RO2 + NO

  5. CIMS Method Heated Inlet R-C(O)O2NO2 → R-C(O)O2 + NO2 Detection I- + R-C(O)O2 → RC(O)O- + IO Zero R-C(O)O2 + NO → R-C(O)O + NO2 or destroy PAN thermally before entering instrument

  6. Then and Now Time resolution 1.25-2.5 min 0.25-2 sec Limit of detection 2-3 pptv < 2 pptv/sec Sensitivity 15-30 cps/pptv Background <200 cps # of PAN species 4 8+ Instrument weight ~425 lbs ~360 lbs (incl. Gases) (smaller Instr. coming) Operator Yes/No No!

More Related