Experiment: 2014 FIXCIT Study_20140106_Isoprene/Ozone/Water_Hydroxyl radical_No Seed_Isoprene + OH + O3, low NO, dry, no seeds


Name: 2014 FIXCIT Study_20140106_Isoprene/Ozone/Water_Hydroxyl radical_No Seed_Isoprene + OH + O3, low NO, dry, no seeds
Date: 2014-01-06

2014 FIXCIT Study

Seinfeld chambers

Experiment Set
FIXCIT experiments

Explore OH yield, product formation (carbonyls, peroxides, organic acids, and others), and Ozone-related GTHOS interference. Investigate any instrumental interferences of high ozone levels.

Experiment went well, lots of products were made, both by OH and O3 + isoprene chemistry. A significant amount of the isoprene mass was converted to hydroxymethylhydroperoxide (HMHP) at this RH, as expected based on previous CIT measurements. Experiment time was shorter than hoped, due to bag volume depleting too quickly. LIF OHR instrument was taken off bag at 1.5 h mark to conserve bag volume. The "end" of the experiment was when CF3O- CIMS saw that product formation stabilized and when PTRMS and GC-FID saw that isoprene was all gone - this happened at approximately 16:15. At reaction end (although it's technically still going in the bag), we did a test for some instruments to see if sampling directly from a port into the chamber gives the same answer as from a common sampling line. For I/A CIMS, CF3O- CIMS, and PTRMS, there does not appear to be significant differences. For O3/NOx, there appears to be a difference in the beginning of sampling, and these instruments now will be on their own line when O3 measurements are more critical. AMS reports losing ~ 30% of particle mass through a longer inlet. GC-FID tested out trapping methods, with limited success but will continue to work on it. The flow rate through LIF OHR was higher than expected, but this will be worked on tomorrow when this instrument will be off. At the end of the experiment, UV lights were also turned on at 100% for ~40 min. Photolysis of some species seen by CF3O- CIMS was observed. CRM OHR was not on the bag today, but at the end of the day reported success in measuring OHR of pyrrole and expects to be on tomorrow. Preparations for upcoming experiment, starting this evening, started approximately 19:00.

Additional Notes
Instrument Status: TD LIF - up PTRMS - up GTHOS - up LIF OHR - up, measuring partially, down tomorrow to tune sampling flow CRM OHR - down today, up tomorrow NO CL - up GLY LIP - down FOR LIF - down I/A CIMS - up NCIMS - up RHTO3 - up GC FID - up AMS - up TQC1 - up TQC2 - up TOFCIMS - up

Experiment Details


  • Gas phase chemical reaction
Temperature: 25
Relative Humidity: 5
Seeded Experiment: No
Fuchs Adjusted Surface Area:
Condensation sink rate coefficient: 5
Reaction type:
Oxidant Name: Hydroxyl radical
Initial Oxidant Concentration Value: 1e6 (molecules_per_cubic_centimeter)
RO2 Main Fate: HO2
RO2 Lifetime: (Seconds)
Pressure: 750 Torr

Data Set plots
Choose a file: Choose the X-Axis:

Experiment Set Details

Name: FIXCIT experiments
Time format and units: Seconds past midnight
The Focused Isoprene eXperiment at the California Institute of Technology (FIXCIT) was a collaborative study at the atmospheric chambers of Caltech during January 2014. FIXCIT is the laboratory component of SOAS, and is aimed toward (1) better understanding the chemical details behind ambient observations relevant to the southeastern United States, (2) advancing the knowledge of atmospheric oxidation mechanisms of important biogenic hydrocarbons, and (3) characterizing the behavior of field instrumentation using authentic standards. A series of chamber experiments was conducted to investigate the oxidation of isoprene, α-pinene, methacrolein, pinonaldehyde, acylperoxy nitrates, isoprene hydroxy nitrates (ISOPN), isoprene hydroxy hydroperoxides (ISOPOOH), and isoprene epoxydiols (IEPOX). Pinonaldehyde and isomer-specific standards of ISOPN, ISOPOOH, and IEPOX were synthesized, enabling study of the oxidation mechanisms and instrument responses for these compounds.


  • Allen H. Goldstein UC Berkeley
  • William H. Brune Penn State University
  • Ronald C. Cohen UC Berkeley
  • Delphine K. Farmer Colorado State University
  • Manjula R. Canagaratna Aerodyne
  • Douglas R. Worsnop Aerodyne
  • Jose L. Jimenez University of Colorado Boulder
  • Frank N. Keutsch Harvard
  • Saewung Kim UC Irvine
  • Alex B. Guenther UC Irvine
  • John E. Mak SUNY Stonybrook
  • Geoffrey S. Tyndall NCAR
  • Denise D. Montzka NCAR
  • Andrew J. Weinheimer NCAR
  • Alam Hasson Fresno State


Principal investigators:

Paul O. Wennberg
Phone: 626 395 2447
E-mail: wennberg@caltech.edu
OrcID: 0000-0002-6126-3854

John H. Seinfeld
Phone: 626-395-4635
E-mail: seinfeld@caltech.edu
OrcID: 0000-0003-1344-4068

John D. Crounse
Phone: 626-395-8655
E-mail: crounjd@caltech.edu
OrcID: 0000-0001-5443-729X

Tran B Nguyen
Phone: 5307525987
E-mail: tbn@ucdavis.edu
OrcID: 0000-0001-9206-4359

Data Manager:

Tran B. Nguyen
Phone: 5307525987
E-mail: tbn@ucdavis.edu


Reactant Compound type Concentration Concentration units
Isoprene (6557)
  • Alkene
91 Parts Per Billion
Ozone (24823) 615 Parts Per Billion
Water (962)
  • O-heterocycle

20140106_expTimeline.csv Timeline

Time (America/Los_Angeles) Action
8:25 Start NO/CO span 2|20|off|35.0
8:40 NO 84.96 Nox 87.4 CO 16.46
Start GPT span 2|20|0.7|35.0
8:55 NO 61.52 Nox 86.91 CO 16.46
Start O3 span 2|20|0.7|off
9:29 O3 35.89
Start E-W-Z sampling
9:30 Fill air off
9:54 Air Handler on Heater on
9:32 Inject 100uL PFH into both bags
9:46 Inject 380uL H2O2 to both bags at 50~70C
10:14 Inject 20uL DEGEE to both bags at 71~95C
11:00 Mix E-W bags for 10 mins
11:14 Close valve 14
11:15 Inject (2.532-0.025) torr x 0.253L NO to East bag
11:23 Mix East for 1 min
GC2 sampling until 11:10
11:53 Only see 4ppb on East
Inject (1.659-0.03) torr x 0.253L NO to East bag
12:03 Mix East for 1 min
12:15 BLs on, Heater off
15:05 AMS on East
Valve not open until 17:50
18:47 BLs off, Air Handler off

Light Flux Characterizations:
2013-12-16 (#17)
Particle Loss Characterizations:
2013-03-06 (#12)
Vapor Loss Characterizations:
2015-05-11 (#6)

Chamber Details

Name: Seinfeld chambers
Volume in cubic meters: 22
Shape: Rectangular Prism
Surface area in cubic meters: 48
Flow Mode: Batch
Flow through rate in liters per minute:
Body Material: Teflon
Body thickness: 2
Replacement date:
Replacement frequency: As needed
Cleaning method: Flushing with air Flushing with air with UV lights on Oxidation
o3 background: < 0.5 ppb
nox background: 40 ppt
Particle background in micrograms per cubic meter: < 0.01 ug/m3
Air filtration method: Custom filtration canisters to remove NOx, hydrocarbons, water, particles, ozone, SOx from pressurized ambient air.
Mixing method: 1
Mixing method material: Pulsed air jets, manually actuated
Temparature Control: Yes
Temparature measurements recorded: Yes
Temparature range (min degrees celcius): 10
Temparature range (max degrees celcius): 45
Humidity Control: Yes
Humidity Measurements Recorded: Yes
Relative humidity range (min percent): 4
Relative humidity range (max percent): 90
Particle experiment capability: 1
Lights: Yes
Light source type(s): UV black lamps (350 nm centered)
Supplemental information: https://www.worldscientific.com/doi/abs/10.1142/9789813147355_0001
Additional Notes: