Instrument - Triple quadrupole chemical ionization mass spectrometer using CF3O- reagent (Wennberg)
Triple quadrupole chemical ionization mass spectrometer using CF3O- reagent (Wennberg)
What is being measured:
Methylhydroperoxide (CH3OOH), glycolaldehyde, IEPOX (isoprene epoxydiol), ISOPOOH (isoprene hydroxyhydroperoxide)
Custom (Varian TQ)
Data recording software:
Data analysis software:
Raw data time resolution:
Analysis data averaging:
0.5 s averages of raw data. Time resolution of each ion (time spacing between scans) is roughly 40-50 sec.
Sensitivity to temperature (and correction method, if applicable):
Negligible for ions reported.
Sensitivity to relative humidity (and correction method, if applicable):
Each ion is corrected for RH dependent ionization by an RH-dependent calibration factor.
Sample preparation method:
Sample residence time (chamber to instrument) (seconds):
Length of tubing (cm):
Instrument flow rate:
Tubing inner diameter:
Chemical identification method:
By ion fragmentation in the triple quadrupole
Data analysis method:
Analysis by a custom Matlab script
Baseline correction (from subtracting background period before reaction), dilution correction, then application of RH-dependent calibration factor.
Acetic acid (permeation tube), Glycolaldehyde (commercial standard + FTIR analysis), ISOPOOH (synthesized standard), IEPOX (synthesized standard)
Calibration drift estimate:
Uncertainty estimation method:
Uncertainties are estimated from propagating uncertainties in the steps of the absolute calibrations
Link to supplemental information:
St. Clair et al: https://aip.scitation.org/doi/full/10.1063/1.3480552