Comparison
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Results

MEASURAND : Amount-of-substance fraction of Methane in air

NOMINAL VALUES : 1800 nmol/mol and 2200 nmol/mol

Degrees of equivalence Di and expanded uncertainty Ui (k = 2)

Red diamonds : measurement of standards prepared with the amount-of-substance fraction of ~ 1800 nmol/mol
Blue triangles : measurement of standards prepared with the amount-of-substance fraction of ~ 2200 nmol/mol

Comparison
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Results

MEASURAND : Amount-of-substance fraction of Methane in air

NOMINAL VALUES : 1800 nmol/mol and 2200 nmol/mol

Results are presented under A4 printable format in Summary Results (PDF file).

Comparison
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CC comparison
Linked comparison
CCQM-K82
Metrology area, Sub-field Chemistry and Biology, Gases
Description Methane in air : preparative comparison
Time of measurements 2012
Status Approved for equivalence
Final Reports of the comparisons
Measurand Amount-of-substance fraction of methane in air at ambient levels: 1800 nmol/mol to 2200 nmol/mol
Transfer device Gas cylinders
Comparison type Key Comparison
Consultative Committee CCQM (Consultative Committee for Amount of Substance)
Conducted by CCQM (Consultative Committee for Amount of Substance)
Comments

Results published on 10 November 2014

Methane in air

Pilot institute BIPM
Bureau International des Poids et Mesures
BIPM - International Organization
Contact person E. Flores
edgar.flores@bipm.org
+33 1 45 07 70 92
First Name Last Name
wwww@ww.www +356719836 Institute 1 Institute 1 Khmelnitskiy
Pilot laboratory
BIPM

Bureau International des Poids et Mesures, BIPM - International Organization, N/A

KRISS

Korea Research Institute of Standards and Science, Korea, Republic of, APMP

NIM

National Institute of Metrology, China, APMP

NIST

National Institute of Standards and Technology, United States, SIM

NMIJ AIST

National Metrology Institute of Japan, Japan, APMP

NOAA/ESRL

NOAA Earth System Research Laboratory (NOAA/ESRL), WMO - International Organization, SIM

NPL

National Physical Laboratory, United Kingdom, EURAMET

VNIIM

D.I. Mendeleyev Institute for Metrology, Rosstandart, Russian Federation, COOMET

VSL

VSL, Netherlands, EURAMET

Comparison
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Results

MEASURAND : Amount-of-substance fraction of Methane in air

NOMINAL VALUES : 1800 nmol/mol and 2200 nmol/mol

For each cylinder gravimetrically prepared by each laboratory, the key comparison reference value is the value xRi predicted by the linear analysis function for the corresponding analyzer response (ratio to the control cylinder with the cavity ring down spectroscopy method 2, see Section 8 of the Final report), and uRi its associated standard uncertainty.
 

The degree of equivalence of laboratory i with respect to the key comparison reference value is given by a pair of terms:
Di = xi - xRi and its expanded uncertainty (k = 2), Ui
both expressed in nmol/mol.

Comparison
Comparison close
Results

MEASURAND : Amount-of-substance fraction of Methane in air

NOMINAL VALUES : 1800 nmol/mol and 2200 nmol/mol

xRi : amount-of-substance fraction in the cylinder as predicted by the linear analysis function for the corresponding analyzer response (ratio to the control cylinder with the cavity ring down spectroscopy method 2, see Final report)
uRi : standard uncertainty of xRi
xi : value assigned by the participating laboratory i based on gravimetric preparation
ui : standard uncertainty including contributions from verification associated with the assigned value xi