TOGA-HR-TOF

The TOGA-HR-TOF (Trace Organic Gas Analyzer High Resolution Time-of-Flight mass spectrometer) was completed this year. The most recent ACOM instrument, supported by NSF and developed by the ACOM VOC Measurements Group (Eric Apel, Alan Hills, and Rebecca Hornbrook) performed extremely well while deployed on the NSA DC8 aircraft during the NOAA/NASA FIREX-AQ program. Western wildfire smoke was sampled and analyzed during August and prescribed burns in the Southeast U.S. were sampled and analyzed in August and early September. The TOGA-HR-TOF high data acquisition rates is a great match for the TOGA platform that quickly measures a wide range of volatile organic compounds (VOCs), from species containing only one carbon atom to those containing 10 or more. For FIREX-AQ, the TOGA-TOF measured more than 100 VOC species (including oxygenates, biogenics, organic nitrates, nitriles, and halogenates) over an integrated sampling time of 33 seconds or less, with measurements repeated every one minute and 45 seconds. The TOGA-HR-TOF also has the capability to target narrow plumes on demand. The system is highly selective, in part because of the high resolution mass spectra capability, which is critical in analyzing complex VOC mixtures emanating from fires. Additionally, since the TOGA-HR-TOF does not require that compounds being analyzed have to be pre-selected, discovery and identification of new species that have not been specifically targeted for analysis is possible. These features are well suited to the study of fire emissions, which have a highly complex chemical make-up, and the chemical evolution of fire emissions as they age. These same features make the TOGA-TOF a critical component of ACOM’s suite of instruments that will serve ACOM- and University-led science airborne science for years to come.