ICARUS Chamber Experiment: 2014 FIXCIT Study_20140103_ISOPRENE/nitric oxide/hydrogen peroxide_Hydroxyl radical_No Seed_Isoprene + OH, high NO, dry, no seeds

Goals: High NO isoprene oxidation experiment. Interested mainly in working out chamber method for high-NOx condition with this many instruments.Summary: Isoprene injection was conducted as the first step in the consideration of OH reactivity measurement. H2O2 injection proceeded as normally. 4.5 minutes NO injection was conducted to obtain 500 ppb NO level in the chamber. After approximately 30-45 minutes of sampling, instruments reported stable backgrounds so the UV lights were turned on. We have 50% lights on for the high-NOx conditions to slow down the isoprene decay. The bag was not very puffy when instruments started to sample for the background before lights on. For future runs, it might be better to fill the bag before background sampling started. This means the initial concentrations of all the precursors should be ~15% higher than the final desired values. I/A CIMS detected a signal at m/z 90 and they confirmed that this signal is oxalic acid. This might be resulted from the last experiment we did with HCHO injection involved.Organization: 2014 FIXCIT Study Lab Affiliation: California Institute of Technology Chamber: Seinfeld chambersExperiment Category: Gas phase chemical reaction Oxidant: Hydroxyl radical Reactants: ISOPRENE, nitric oxide, hydrogen peroxide Reaction Type: Photooxidation Relative Humidity: 5 Temperature: 26 Pressure: 750 Torr