Development of instrumentation for simultaneous analysis of total non-methane organic carbon and volatile organic compounds in ambient air

Maris, Christophe; Chung, Myeong Y.; Lueb, R.; Krischke, Udo; Meller, Richard; Fox, Matthew J.; Paulson, Suzanne E.

doi:10.1016/s1352-2310(03)00387-x

Cited by 22 publications

(22 citation statements)

References 19 publications

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“…The carbon balance in smog-chamber oxidation studies can provide insight into the potential completeness of current measurements of atmospherically relevant organic composition. For well-studied molecules such as isoprene and m-xylene, the carbon balance is reasonably complete when total VOC measurements are used, but only about half of the isoprene oxidation products and essentially none of the m-xylene oxidation products are detected by traditional, air-sampling GC methods (23). Experiments quantifying the oxidation products of a wide variety of terpenoid compounds show that often much less than 100% of the oxidized carbon is accounted for in the gas and aerosol phases combined (24)(25)(26), as illustrated in Figure 2.…”

Section: Evidence For Additional Organic Compoundsmentioning

confidence: 99%

Known and Unexplored Organic Constituents in the Earth's Atmosphere

Goldstein¹,

Galbally²

2007

Environ. Sci. Technol.

1,441

1,157

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Section: Evidence For Additional Organic Compoundsmentioning

confidence: 99%

Known and Unexplored Organic Constituents in the Earth's Atmosphere

Goldstein¹,

Galbally²

2007

Environ. Sci. Technol.

1,441

1,157

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“…Roberts et al (1998) and Maris et al (2003) determined the total carbon budget of ambient VOCs, but while this information is useful for understanding what fraction of the carbon budget remains unidentified by VOC measurements, it lacks the critical information about how reactive the missing carbon might be for chemical reactions in the atmosphere (e.g. 10 ppbC of isoprene is not equivalent to 10 ppbC of methane for OH reactivity).…”

Section: Introductionmentioning

confidence: 99%

The Comparative Reactivity Method – a new tool to measure total OH Reactivity in ambient air

et al. 2008

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Abstract. Hydroxyl (OH) radicals play a vital role in maintaining the oxidizing capacity of the atmosphere. To understand variations in OH radicals both source and sink terms must be understood. Currently the overall sink term, or the total atmospheric reactivity to OH, is poorly constrained.Here, we present a new on-line method to directly measure the total OH reactivity (i.e. total loss rate of OH radicals) in a sampled air mass. In this method, a reactive molecule (X), not normally present in air, is passed through a glass reactor and its concentration is monitored with a suitable detector. OH radicals are then introduced in the glass reactor at a constant rate to react with X, first in the presence of zero air and then in the presence of ambient air containing VOCs and other OH reactive species. Comparing the amount of X exiting the reactor with and without the ambient air allows the air reactivity to be determined. In our existing set up, X is pyrrole and the detector used is a proton transfer reaction mass spectrometer. The present dynamic range for ambient air reactivity is about 6 to 300 s −1 , with an overall maximum uncertainty of 25% above 8 s −1 and up to 50% between 6-8 s −1 . The system has been tested and calibrated with different single and mixed hydrocarbon standards showing excellent linearity and accountability with the reactivity of the standards. Potential interferences such as high NO in ambient air, varying relative humidity and photolysis of pyrrole within the setup have also been investigated. While interferences due changing humidity and photolysis of pyrrole are easily overcome by ensuring that humidity in the set up does not change drastically and the photolytic loss of pyrrole is measured and taken into account, respectively, NO>10 ppb in ambient air remains a significant interference for the current configuration of the instrument. Field tests in the tropical rainforest of Suriname (∼53 s −1 ) and the urban atmosphere Correspondence to: J. Williams (williams@mpch-mainz.mpg.de) of Mainz (∼10 s −1 ) Germany, show the promise of the new method and indicate that a significant fraction of OH reactive species in the tropical forests is likely missed by current measurements. Suggestions for improvements to the technique and future applications are discussed.

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“…Static methods rely on mixtures of gases in closed containers of known volume, while dynamic processes involve mixing a continuous flow of analyte into a dilution or carrier stream. A comprehensive review of standard generation processes for VOC can be found elsewhere (Barratt, 1981;Namiesnik, 1984;Naganowska-Nowak et al, 2005) Modern static techniques most commonly utilize mixtures of gases in treated high-pressure cylinders (Apel et al, 1998;Rappengluck et al, 2006;Apel et al, 1994). Static techniques are the preferred calibration method for many field and laboratory investigations due to the portability and robust nature of high-pressure gas cylinders.…”

Section: Introductionmentioning

confidence: 99%

“…Total organic carbon (TOC) measurements of gas phase nonmethane hydrocarbons using oxidative catalysts, followed by reduction to methane, have been used in previous work (Maris et al, 2003;Roberts et al, 1998). Ambient VOC levels are frequently below the detection limits of these gas phase TOC measurement techniques, which need to account for the large concentrations of ambient CO 2 , methane, and carbon monoxide and make them unsuitable for ambient analyses.…”

Section: Introductionmentioning

confidence: 99%

Development and validation of a portable gas phase standard generation and calibration system for volatile organic compounds

et al. 2010

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Abstract. We report on the development of an accurate, portable, dynamic calibration system for volatile organic compounds (VOCs). The Mobile Organic Carbon Calibration System (MOCCS) combines the production of gas-phase VOC standards using permeation or diffusion sources with quantitative total organic carbon (TOC) conversion on a palladium surface to CO 2 in the presence of oxygen, and the subsequent CO 2 measurement. MOCCS was validated using three different comparisons: (1) TOC of high accuracy methane standards compared well to expected concentrations (3% relative error), (2) a gas-phase benzene standard was generated using a permeation source and measured by TOC and gas chromatography mass spectrometry (GC-MS) with excellent agreement (<4% relative difference), and (3) total carbon measurement of 4 known gas phase mixtures were performed and compared to a calculated carbon content to agreement within the stated uncertainties of the standards. Measurements from laboratory biomass burning experiments of formic acid by negative-ion proton-transfer chemical-ionization mass spectrometry (NI-PT-CIMS) and formaldehyde by proton transfer reaction-mass spectrometry (PTR-MS), both calibrated using MOCCS, were compared to open path Fourier transform infrared spectroscopy (OP-FTIR) to validate the MOCCS calibration and were found to compare well (R 2 of 0.91 and 0.99, respectively).

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Development of instrumentation for simultaneous analysis of total non-methane organic carbon and volatile organic compounds in ambient air

Cited by 22 publications

References 19 publications

Known and Unexplored Organic Constituents in the Earth's Atmosphere

Known and Unexplored Organic Constituents in the Earth's Atmosphere

The Comparative Reactivity Method – a new tool to measure total OH Reactivity in ambient air

Development and validation of a portable gas phase standard generation and calibration system for volatile organic compounds

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