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
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).
| 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 +33 1 45 07 70 92 |
| 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 |
This page proposes print-out on A4 paper (portrait) of the comparison details (best printed out using a black and white printer).
Please, select items to be printed out, then click on "OK" :
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: |
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
