84th AMS Annual Meeting

Monday, 12 January 2004
Hydroperoxyl Radical Detection by MCLA Chemiluminescense
Hall 4AB
Judith B. Weinstein-Lloyd, SUNY, Old Westbury, NY; and J. Zheng and S. R. Springston
Poster PDF (171.0 kB)
Hydroperoxyl radical (HO2) is produced from the reaction of hydroxyl radicals with organic compounds in the atmosphere, and by photolysis of formaldehyde. Detection of HO2 is a challenge due to their low abundance and short lifetime. We have developed a flow injection method for HO2 analysis that is based on the chemiluminescence produced when an aqueous solution of HO2 and its conjugate base O2- react with MCLA, a synthetic analog of the luciferin from the crustacean Cypridina. The technique is linear at least up to 1-ÁM HO2(aq), and has a minimum detection limit of 0.1 nM. We calibrate the instrument with stable aqueous O2- standards produced in submicromolar concentration using 60Co gamma radiolysis. The method is simple, low-cost and has minimal size and power requirements, making it an attractive candidate for field deployment. We have demonstrated that the technique can be used to measure atmospheric HO2 radicals following collection into aqueous solution in a glass coil scrubber.

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