Preparation of known concentrations of gases and vapors with permeation devices calibrated gravimetrically

Scaringelli, Frank P.; O'Keeffe, Andrew E.; Rosenberg, Ethan; Bell, J.P.

doi:10.1021/ac60290a012

Cited by 127 publications

(49 citation statements)

References 12 publications

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“…Alternatively, known amounts of SO2 in air may be prepared by use of permeation tubes at constant temperature and an appropriate gas dilution system. 29 The above reference method represents a highly specific and accurate method for the determination of SO 2 in the ambient air, within the specified standard deviation and confidence limits.…”

Section: Sulfur Dioxidementioning

confidence: 90%

A Critical Review

Katz

1980

Journal of the Air Pollution Control Association

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Section: Sulfur Dioxidementioning

confidence: 90%

A Critical Review

Katz

1980

Journal of the Air Pollution Control Association

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“…O'Keeffe and Ortman, 1966;Scaringelli et al, 1970;Brewer et al, 2011;Flores et al, 2012;Haerri et al, 2017). It is routinely used at METAS following a procedure in compliance with international standards (ISO 6145-10, 2002;ISO 6145-7, 2009).…”

Section: Permeationmentioning

confidence: 99%

Dynamic–gravimetric preparation of metrologically traceable primary calibration standards for halogenated greenhouse gases

et al. 2018

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Abstract. For many years, the comparability of measurements obtained with various instruments within a global-scale air quality monitoring network has been ensured by anchoring all results to a unique suite of reference gas mixtures, also called a “primary calibration scale”. Such suites of reference gas mixtures are usually prepared and then stored over decades in pressurised cylinders by a designated laboratory. For the halogenated gases which have been measured over the last 40 years, this anchoring method is highly relevant as measurement reproducibility is currently much better (< 1 %, k = 2 or 95 % confidence interval) than the expanded uncertainty of a reference gas mixture (usually > 2 %). Meanwhile, newly emitted halogenated gases are already measured in the atmosphere at pmol mol−1 levels, while still lacking an established reference standard. For compounds prone to adsorption on material surfaces, it is difficult to evaluate mixture stability and thus variations in the molar fractions over time in cylinders at pmol mol−1 levels. To support atmospheric monitoring of halogenated gases, we create new primary calibration scales for SF6 (sulfur hexafluoride), HFC-125 (pentafluoroethane), HFO-1234yf (or HFC-1234yf, 2,3,3,3-tetrafluoroprop-1-ene), HCFC-132b (1,2-dichloro-1,1-difluoroethane) and CFC-13 (chlorotrifluoromethane). The preparation method, newly applied to halocarbons, is dynamic and gravimetric: it is based on the permeation principle followed by dynamic dilution and cryo-filling of the mixture in cylinders. The obtained METAS-2017 primary calibration scales are made of 11 cylinders containing these five substances at near-ambient and slightly varying molar fractions. Each prepared molar fraction is traceable to the realisation of SI units (International System of Units) and is assigned an uncertainty estimate following international guidelines (JCGM, 2008), ranging from 0.6 % for SF6 to 1.3 % (k = 2) for all other substances. The smallest uncertainty obtained for SF6 is mostly explained by the high substance purity level in the permeator and the low SF6 contamination of the matrix gas. The measured internal consistency of the suite ranges from 0.23 % for SF6 to 1.1 % for HFO-1234yf (k=1). The expanded uncertainty after verification (i.e. measurement of the cylinders vs. each others) ranges from 1 to 2 % (k = 2). This work combines the advantages of SI-traceable reference gas mixture preparation with a calibration scale system for its use as anchor by a monitoring network. Such a combined system supports maximising compatibility within the network while linking all reference values to the SI and assigning carefully estimated uncertainties. For SF6, comparison of the METAS-2017 calibration scale with the scale prepared by SIO (Scripps Institution of Oceanography, SIO-05) shows excellent concordance, the ratio METAS-2017 / SIO-05 being 1.002. For HFC-125, the METAS-2017 calibration scale is measured as 7 % lower than SIO-14; for HFO-1234yf, it is 9 % lower than Empa-2013. No other scale for HCFC-132b was available for comparison. Finally, for CFC-13 the METAS-2017 primary calibration scale is 5 % higher than the interim calibration scale (Interim-98) that was in use within the Advanced Global Atmospheric Gases Experiment (AGAGE) network before adopting the scale established in the present work.

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“…The required partial pressures of sulfur dioxide were achieved using the permeation-tube technique described by Scaringelli et al 3 The FEP Teflon tubes were prepared in lengths from 20 to 250 mm and were filled with liquid sulfur dioxide. The tubes were stored over silica gel and anhydrous sodium hydroxide in a desiccator at 5°C until required.…”

Section: Experimental Apparatusmentioning

confidence: 99%