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Online Volatile Organic Compound Measurements Using a Newly Developed Proton-Transfer Ion-Trap Mass Spectrometry Instrument during New England Air Quality StudyIntercontinental Transport and Chemical Transformation 2004: Performance, Intercomparison, and Compound Identification

Carsten Warneke,*^†^‡ Shuji Kato,^§ Joost A. de Gouw,^†^‡ Paul D. Goldan,^† William C. Kuster,^† Min Shao, Edward R. Lovejoy,^† Ray Fall,^‡^§ and Fred C. Fehsenfeld^†^‡

National Oceanic and Atmospheric Administration, Aeronomy Laboratory, 325 Broadway, Boulder, Colorado 80305, Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, and Department of Environmental Sciences, Peking University, Beijing, China

Environ. Sci. Technol., 2005, 39 (14), pp 5390–5397

DOI: 10.1021/es050602o

Publication Date (Web): June 17, 2005

Corresponding author phone: 001-303-497-3601; e-mail: Carsten.Warneke@noaa.gov.

†

National Oceanic and Atmospheric Administration.

‡

Cooperative Institute for Research in Environmental Studies, University of Colorado.

Department of Chemistry and Biochemistry, University of Colorado.

Peking University.

Abstract

We have used a newly developed proton-transfer ion-trap mass spectrometry (PIT-MS) instrument for online trace gas analysis of volatile organic compounds (VOCs) during the 2004 New England Air Quality StudyIntercontinental Transport and Chemical Transformation study. The PIT-MS instrument uses proton-transfer reactions with H₃O⁺ ions to ionize VOCs, similar to a PTR-MS (proton-transfer reaction mass spectrometry) instrument but uses an ion trap mass spectrometer to analyze the product ions. The advantages of an ion trap are the improved identification of VOCs and a near 100% duty cycle. During the experiment, the PIT-MS instrument had a detection limit between 0.05 and 0.3 pbbv (S/N = 3 (signal-to-noise ratio)) for 2-min integration time for most tested VOCs. PIT-MS was used for ambient air measurements onboard a research ship and agreed well with a gas chromatography mass spectrometer). The comparison included oxygenated VOCs, aromatic compounds, and others such as isoprene, monoterpenes, acetonitrile, and dimethyl sulfide. Automated collision-induced dissociation measurements were used to determine the contributions of acetone and propanal to the measured signal at 59 amu; both species are detected at this mass and are thus indistinguishable in conventional PTR-MS.

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