Measurement of Gaseous HAP Emissions from Idling Aircraft as a Function of Engine and Ambient Conditions (2012) / Chapter Skim
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Appendix E - Quality Assurance Documentation for Analytical Methods
Appendix E - Quality Assurance Documentation for Analytical Methods
Pages 88-102
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From page 88... ...
Quality Assurance Description for Carbon Dioxide This section includes a technical description of the different carbon dioxide measurement instruments deployed in ACRP 02-03a measurement campaigns at MDW 2009, DAL2010, and MDW 2010. Three different measurements of carbon dioxide were made with two employed on the sample line used for gas phase species characterization and one on the sample line used to characterize particulate characteristics.
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Although TILDAS methods using tunable diode lasers have been widely used for a variety of trace gas measurements (Sachse et al. 1987, Zahniser et al.
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The pulsed quantum cascade lasers in this instrument have a broader linewidth compared to the cw lasers, and the laser lineshape is not always symmetric. Any multi-mode character in the laser would also contribute to the QCL measurement being low.
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Proton Transfer Reaction and NO+ Mass Spectrometry Method Overview Proton transfer reaction mass spectrometry (PTR-MS) is a chemical ionization mass spectrometry technique that utilizes H3O+ as the principal reagent ion.
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It is important to note that the primary components of air: N2, O2, Ar, CO2, and the alkanes all have proton affinities less than water and thus do not react with H3O+. Most other organic substances except for acetylene and ethene react with H3O+ via a proton transfer reaction, reaction 1.
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From page 93... ...
Quantification Quantification of the PTR-MS ion signals is possible directly from first principles, but is most reliably done via calibration with certified gas standards. In this test the concentrations reported were evaluated from calibrated response factors, except for naphthalene for which a calibration standard was not available.
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The outflow from the mass flow controllers was mixed together and delivered to the sample inlets of the two PTR-MS instruments and GC/FID. In all cases, the PTR-MS instruments and the GC/FID were all calibrated using the same gas mixtures.
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, because the quadrupole mass spectrometer lacks the resolution to separate these compounds. This result is illustrated in the accompanying Figure E-8, which shows the GC/PTR-MS trace of m/z 107 taken from a jet aircraft engine burning JP8 fuel.
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As a semivolatile it will be the first to condense onto the sample lines or existing particles and thus serves as a valuable marker for evaluating the integrity of the extraction probes and the associated sample lines. The precision of the sensitivity factors derived from the individual calibration experiments generally falls within the +/-10% level.
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The chromatographic column, Restex MXT-1, utilizes a temperature program where the temperature is held at 50°C for 4 minutes, ramped at 10°C per minute to 200°C and then held for 4 minutes. Calibration of the detector response, adsorbent trapping characteristic and column retention characteristics of the GC/FID were evaluated by analyzing a diluted mixture of the certified gas standard used to calibrate the PTR-MS.
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Quantification of exhaust samples assumes that the peak area/ppbC response factor of 0.73 expressed by benzene and toluene is correct. Two engine exhaust gas samples were analyzed by the GC/FID.
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The PTR-MS measurements reflect the average of the concentrations recorded while the GC sample was being taken. The C2-benzenes represent the sum of ethyl benzene and the three xylene isomers.
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The FID instrument was operated during the first day in its rack using manual calibration protocols recommended in the manual. This instrument operated at its highest gain setting and experienced frequent drifts in the zero signal level, sometimes beyond the scale of the digitization range.
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2007. Quantification of Aircraft Engine Hydrocarbon Emissions Using Proton Transfer Reaction Mass Spectrometry.
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TRB Transportation Research Board TSA Transportation Security Administration U.S.DOT United States Department of Transportation
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