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| Titel |
A range of newly developed mobile generators to dynamically produce
SI-traceable reference gas mixtures for reactive compounds at atmospheric
concentrations |
| VerfasserIn |
Daiana Leuenberger, Céline Pascale, Myriam Guillevic, Andreas Ackermann, Bernhard Niederhauser |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250147603
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| Publikation (Nr.) |
 EGU/EGU2017-11791.pdf |
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| Zusammenfassung |
| Three new mobile facilities have been developed at METAS to dynamically generate
SI-traceable reference gas mixtures for a variety of reactive compounds at atmospheric
amount of substance fractions and at very low levels of uncertainty (Ux < 3%). We present
three new portable “Reactive Gas Standard ReGaS” reference gas generators for the
realisation of the following substances:
ReGaS1: Ammonia and nitrogen dioxide in the nmol/mol (ppb) range
ReGaS2: Volatile organic compounds (VOCs), e.g. limonene, alpha-pinene,
MVK, MEK in the nmol/mol (ppb) range
ReGaS-3: Fluorinated gases (F-gases, i.e. containing fluorine atoms) in the
pmol/mol (ppt) range
These three mobile generators have been designed and manufactured at METAS in the
framework of the three EMRP projects MetNH3, KEY-VOCs and HIGHGAS.
The method is based on permeation and subsequent dynamic dilution: A permeation tube
containing the pure substance (e.g. NH3) is stored in the permeation chamber at constant
temperature, pressure and matrix gas flow (N2, purified air, synthetic air). Under such
conditions the pure substance permeates at constant rate into the matrix gas and
can be diluted thereafter to the desired amount fractions in one or two subsequent
steps.
The permeation rate (mass loss over time) of the permeation tube is precisely calibrated in
a fully traceable magnetic suspension balance. The carrier gas is previously purified from the
compounds of interest using commercially available purification cartridges. The permeation
chambers of ReGaS2 and ReGaS3 have multiple individual cells allowing for the generation
of mixtures containing up to 5 different components if required. ReGaS1 allows for the
generation of one-component mixtures only.
These primary mixtures are then diluted to the required amount of substance fractions using
thermal mass flow controllers for full flexibility and adaptability of the generation process
over the entire range of possible concentrations.
In order to considerably reduce adsorption/desorption processes and thus stabilisation
time, all electro-polished stainless steel parts of ReGaS1 and ReGaS2 in contact with the
reference gas mixtures are passivated with SilcoNert2000® surface coating.
These three state-of-the-art mobile reference gas generators are applicable under both,
laboratory and field conditions. Moreover the dynamic generation method can be adapted and
applied to a large variety of molecules (e.g. BTEX, CFCs, HCFCs, HFCs and other
refrigerants) and is particularly suitable for reactive gas species and/or at concentration
ranges which are unstable when stored in pressurised cylinders.
Acknowledgement: This work was supported by the European Metrology Research
Programme (EMRP). The EMRP is jointly funded by the EMRP participating countries
within EURAMET and the European Union |
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