Proton transfer reaction mass spectrometry at high drift tube pressure

Hanson, David R.; Greenberg, J.; Henry, Bruce; Kosciuch, E.

doi:10.1016/s1387-3806(02)00924-7

Cited by 44 publications

(46 citation statements)

References 21 publications

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“…26), 40) Indeed, the drift velocity of an ion in the drift tube is proportional to the E/N value. 41) The detection sensitivity at the E/N value of 40 Td was increased only for polar molecules such as acetaldehyde and acetone, while it decreased for nonpolar molecules, probably due to di#erences in reactions with the water-clustered hydronium ions. 42) Characteristics of the mass spectra of C 1 ῎C 5 alkyl nitrates have been examined systematically by our group.…”

Section: Resultsmentioning

confidence: 94%

Proton Transfer Reaction Time-of-Flight Mass Spectrometry at Low Drift-Tube Field-Strengths Using an H<sub>2</sub>O-Rare Gas Discharge-Based Ion Source

Inomata

Tanimoto

Aoki

2008

J. Mass Spectrom. Soc. Jpn.

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A discharge-based proton transfer reaction (PTR) ion source was operated using a mixture of H2O and rare gases such as He, Ne, Ar, and Kr in combination with a custom-built time-of-flight (TOF) mass spectrometer. In contrast to an "H2O-only" discharge, which usually functions above a field strength (E/N) of 100 Td for a drift tube, an "H2O῎rare gas"-based discharge was operated successfully at E/N values between 30 and 50 Td. (E is the electric field strength (V cm ῎1 ), N is the bu#er gas number density (molecule cm ῎3 ), and 1 Td῏10 ῎17 cm 2 V molecule ῎1 .) The intensity of primary ions (H3O ῍ ῌ(H2O)n) generated in the "H2O῎rare gas" discharge was comparable to that in the "H2O-only" discharge. Although detection sensitivities decreased for nonpolar molecules such as isoprene, benzene, toluene, and p-xylene, they increased for polar molecules such as acetone and acetaldehyde. This suggests that the operation of the PTR-TOF mass spectrometer at low drift-tube field-strengths improves both the detection sensitivity and selectivity for the polar molecules. In addition, fragmentation in the drift tube was suppressed significantly for fragile species such as methyl nitrate, in the low E/N operation.

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Section: Resultsmentioning

confidence: 94%

Proton Transfer Reaction Time-of-Flight Mass Spectrometry at Low Drift-Tube Field-Strengths Using an H<sub>2</sub>O-Rare Gas Discharge-Based Ion Source

Inomata

Tanimoto

Aoki

2008

J. Mass Spectrom. Soc. Jpn.

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“…This required monitoring reactant concentrations entering and exiting the aerosol growth chamber and the aerosol size distribution leaving the chamber. Ozone concentrations were measured using a 2B Technologies Model 202 ozone monitor, which had a time resolution of 5 s. Biogenic VOC concentrations were monitored with a proton-transfer-reaction mass spectrometer (PTR-MS) constructed in house at NCAR (Hanson et al, 2002), based on a technique first developed by Lindinger et al (1998). The proton transfer reaction is a very soft ionization technique, so that the fragmentation of large organic molecules is minimized.…”

Section: Sampling Instrumentationmentioning

confidence: 99%

Direct measurement of particle formation and growth from the oxidation of biogenic emissions

et al. 2006

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Abstract.A new facility has been developed to investigate the formation of new particles from the oxidation of volatile organic compounds emitted from vegetation. The facility consists of a biogenic emissions enclosure, an aerosol growth chamber, and the associated instrumentation. Using the facility, new particle formation events have been induced through the reaction of ozone with three different precursor gas mixtures: an α-pinene test mixture and the emissions of a Holm oak (Quercus ilex) specimen and a loblolly pine (Pinus taeda) specimen. The results demonstrate the variability between species in their potential to form new aerosol products. The emissions of Q. ilex specimen resulted in fewer particles than did α-pinene, although the concentration of monoterpenes was roughly equal in both experiments before the addition of ozone. Conversely, the oxidation of P. taeda specimen emissions led to the formation of more particles than either of the other two gas mixtures, despite a lower initial terpenoid concentration. These variations can be attributed to differences in the speciation of the vegetative emissions with respect to the α-pinene mixture and to each other. Specifically, the presence of β-pinene and other slower-reacting monoterpenes probably inhibited particle formation in the Q. ilex experiment, while the presence of sesquiterpenes, including β-caryophyllene, in the emissions of the P. taeda specimen were the likely cause of the more intense particle formation events observed during that experiment.

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“…The lab-built instrument has been described in detail previously (Hanson et al, 2002). In the technique, a proton (from H 3 O + ) was transferred to the VOC reactant by soft collision in a drift tube and the resulting ion passed through an orifice into a quadrupole mass spectrometer.…”

Section: Proton Transfer Reaction Mass Spectrometry (Ptrms)mentioning

confidence: 99%

Volatile organic emissions from the distillation and pyrolysis of vegetation

et al. 2006

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Abstract. Leaf and woody plant tissue (Pinus ponderosa, Eucalyptus saligna, Quercus gambelli, Saccharum officinarum and Oriza sativa) were heated from 30 to 300 • C and volatile organic compound (VOC) emissions were identified and quantified. Major VOC emissions were mostly oxygenated and included acetic acid, furylaldehyde, acetol, pyrazine, terpenes, 2,3-butadione, phenol and methanol, as well as smaller emissions of furan, acetone, acetaldehyde, acetonitrile and benzaldehyde. Total VOC emissions from distillation and pyrolysis were on the order of 10 gC/kgC dry weight of vegetation, as much as 33% and 44% of CO 2 emissions (gC(VOC)/gC(CO 2 )) measured during the same experiments, in air and nitrogen atmospheres, respectively.The emissions are similar in identity and quantity to those from smoldering combustion of woody tissue and of different character than those evolved during flaming combustion. VOC emissions from the distillation of pools and endothermic pyrolysis under low turbulence conditions may produce flammable concentrations near leaves and may facilitate the propagation of wildfires. VOC emissions from charcoal production are also related to distillation and pyrolysis; the emissions of the highly reactive VOCs from production are as large as the carbon monoxide emissions.

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Proton transfer reaction mass spectrometry at high drift tube pressure

Cited by 44 publications

References 21 publications

Proton Transfer Reaction Time-of-Flight Mass Spectrometry at Low Drift-Tube Field-Strengths Using an H<sub>2</sub>O-Rare Gas Discharge-Based Ion Source

Proton Transfer Reaction Time-of-Flight Mass Spectrometry at Low Drift-Tube Field-Strengths Using an H<sub>2</sub>O-Rare Gas Discharge-Based Ion Source

Direct measurement of particle formation and growth from the oxidation of biogenic emissions

Volatile organic emissions from the distillation and pyrolysis of vegetation

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