Carbonyls and NO2 in Diesel Emissions
Simultaneous Determination of Carbonyls and NO2 in Exhausts of Heavy Duty Diesel Trucks and Transit Buses by HPLC Following 2,4-Dinitrophenylhydrazine-Cartridge Collection
- Shida Tang, Thomas Lanni, Bureau of Mobile Sources and Technology Development, Division of Air Resources, New York State Department of Environmental Conservation, Albany, New York, USA
- Lisa Graham, Emissions Research and Measurement Division, Environment Canada, Ottawa, Ontario, Canada
- Xianliang Zhou, Wadsworth Center, New York State Department of Health, Albany, New York, USA
A method combining 2,4-dinitrophenylhydrazine (DNPH) cartridge sampling and high performance liquid chromatography (HPLC) analysis has been used for the measurement of carbonyl and NO2 emissions from heavy-duty diesel trucks and transit buses. The reaction of NO2 with DNPH allows for the simultaneous and unambiguous determination of NO2 and carbonyl concentrations in exhaust samples. The potential co-elution of the NO2-DNPH derivative with the formaldehyde-DNPH derivative under certain chromatographic conditions was investigated. Successful separation of these two species was achieved allowing for simultaneous determination of carbonyls and NO2 in the exhaust samples collected from heavy-duty diesel (HDD) trucks and diesel, diesel-electric hybrid, diesel equipped with the continuously regenerating technology (CRT™) particle traps and compressed natural gas (CNG) transit buses tested over various drive cycles. Elevated NO2 emissions from CRT™-equipped buses were observed. The NO2/NOx volume ratios for HDD trucks and transit buses are discussed. A comparison of the DNPH derivatization with HPLC/UV-Visible detection method with a chemiluminescence analyzer method for NO2 measurement is presented for a limited number of diesel/CRT™ and CNG buses.