Barkley Sive (R), Yong Zhou (L) and the MMR-GC during the AIRMAP 2004 intensive campaign at Appledore Island.

An AIRMAP team led by Dr. Barkley Sive of the Climate Change Research Center has been developing a revolutionary new system for measuring volatile organic compounds (VOC’s). The instrument, referred to as the MMR-GC, combines an innovative cooling unit, which concentrates samples by reaching temperatures as low as liquid nitrogen, coupled to a gas chromatograph. Prior to this development, the measurement of VOC’s required the use of liquid nitrogen or solid adsorbents, both of which posed limitations. Using nitrogen is labor intensive, and can limit sampling locations due to the large volumes of the gas needed. Solid adsorbents, while applicable in remote automated operations, have been shown to be unreliable for many trace gases. The newly developed MMR-GC system will allow researchers to measure up to 98 gases with remarkable precision, in areas that were previously impractical. Remote field measurements will also be possible for longer periods of time, and with less intervention, than previous instruments required.

AIRMAP measuring station at Appledore Island. Photo Kevan Carpenter

The instrument’s performance was tested during the summer of 2004, at the AIRMAP site located on Appledore Island, off the coast of New Hampshire. The MMR-GC produced quantitative results similar to those of a Proton Transfer Reaction-Mass Spectrometer (PTR-MS), and to canister samples that were analyzed manually, using gas chromatography at a University of New Hampshire laboratory. The MMR-GC has since proven its reliability by running continuously from November 2005 through the present (July 2006). The development team is currently working on the next incarnation, which will be able to reach even lower temperatures, more rapidly, thus reducing measurement response times.