Evaluation of the permeability of formaldehyde and water through a permeation tube for the preparation of an accurate formaldehyde reference gas mixture

The Analyst ◽  
2013 ◽  
Vol 138 (22) ◽  
pp. 6930 ◽  
Author(s):  
Nobuyuki Aoki ◽  
Kenji Kato ◽  
Reiji Aoyagi ◽  
Masahiko Wakayama
Keyword(s):  
Gas Mixture ◽  
Permeation Tube ◽  
Reference Gas Mixture

A robot for weighing syringes used in reference gas mixture preparation

Metrologia ◽  
2012 ◽  
Vol 49 (4) ◽  
pp. 446-454 ◽  
Author(s):  
I van Andel ◽  
A M H van der Veen ◽  
E T Zalewska
Keyword(s):  
Gas Mixture ◽  
Mixture Preparation ◽  
Reference Gas Mixture

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

2018 ◽  
Vol 11 (6) ◽  
pp. 3351-3372 ◽  
Author(s):  
Myriam Guillevic ◽  
Martin K. Vollmer ◽  
Simon A. Wyss ◽  
Daiana Leuenberger ◽  
Andreas Ackermann ◽  
...  
Keyword(s):  
Sulfur Hexafluoride ◽  
International System ◽  
Molar Fraction ◽  
Monitoring Network ◽  
Gas Mixtures ◽  
Gas Mixture ◽  
Expanded Uncertainty ◽  
Combined System ◽  
System Of Units ◽  
Reference Gas Mixture

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.

scholarly journals Development of Primary Reference Gas Mixture of CF4 and SF6 in N2 as CRM for Measurements of Their Emission from Semiconductor Process Tool

2009 ◽  
Vol 58 (5) ◽  
pp. 407-416 ◽  
Author(s):  
Nobuhiro Matsumoto ◽  
Fumiko Noguchi ◽  
Nobuyuki Aoki ◽  
Kenji Kato ◽  
Ryuichiro Isaki ◽  
...  
Keyword(s):  
Gas Mixture ◽  
Primary Reference ◽  
Reference Gas Mixture ◽  
Semiconductor Process

QUICK-RESPONSE METHOD FOR PREVENTING GAS MIXTURE PHOTOTHERMAL IGNITION

2016 ◽  
pp. 57-61
Author(s):  
Y. Polyakov ◽  
◽  
I. Begishev ◽  
A. Belikov ◽  
◽  
...  
Keyword(s):  
Gas Mixture ◽  
Quick Response ◽  
Response Method
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