MEASURAND : pH value of tetroxalate buffer
Measurements at 15 °C
NOMINAL VALUE : pH ~ 1.7
Degrees of equivalence Di and expanded uncertainty Ui (k = 2)
Open symbols show values from laboratories in Associate States and Economies of the CGPM
MEASURAND : pH value of tetroxalate buffer
Measurements at 25 °C
NOMINAL VALUE : pH ~ 1.7
Degrees of equivalence Di and expanded uncertainty Ui (k = 2)
Open symbols show values from laboratories in Associate States and Economies of the CGPM
MEASURAND : pH value of tetroxalate buffer
Measurements at 37 °C
NOMINAL VALUE : pH ~ 1.7
Degrees of equivalence Di and expanded uncertainty Ui (k = 2)
Open symbols show values for laboratories in Associate States and Economies of the CGPM
MEASURAND : pH value of tetroxalate buffer
Measurements at 15 °C
NOMINAL VALUE : pH ~ 1.7
Degrees of equivalence Di and expanded uncertainty Ui (k = 2)
Results are presented under A4 printable format in Summary Results (.PDF file).
MEASURAND : pH value of tetroxalate buffer
Measurements at 25 °C
NOMINAL VALUE : pH ~ 1.7
Degrees of equivalence Di and expanded uncertainty Ui (k = 2)
BIM: degree of equivalence computed with revised values
Results are presented under A4 printable format in Summary Results (.PDF file).
MEASURAND : pH value of tetroxalate buffer
Measurements at 37 °C
NOMINAL VALUE : pH ~ 1.7
Degrees of equivalence Di and expanded uncertainty Ui (k = 2)
BIM: degree of equivalence computed with revised values
Results are presented under A4 printable format in Summary Results (.PDF file).
| Metrology area, Sub-field | Chemistry and Biology, Electrochemistry |
| Description | pH measurement of tetroxalate buffer solutions |
| Time of measurements | 2007 |
| Status | Approved for equivalence |
| Final Reports of the comparisons | |
| Measurand | pH ~ 1.7 |
| Parameters | Temperature: 15 °C, 25 °C and 37 °C |
| Transfer device | Tetroxalate buffer solutions |
| 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 28 July 2009 pH measurement of tetroxalate buffer solutions |
| Pilot institute |
NIST
National Institute of Standards and Technology United States |
| Contact person | Kenneth W. PRATT +1 301 975 4131 |
| Pilot laboratory | |
|---|---|
| NIST |
National Institute of Standards and Technology, United States, SIM |
| BIM |
Bulgarian Institute of Metrology, Bulgaria, EURAMET |
| CENAM |
Centro Nacional de Metrologia, Mexico, SIM |
| CMI |
Czech Metrology Institute, Czechia, EURAMET |
| DFM |
Danish Fundamental Metrology A/S, Denmark, EURAMET |
| GUM |
Glowny Urzad Miar, Central Office of Measures, Poland, EURAMET |
| INMETRO |
Instituto Nacional de Metrologia, Qualidade e Tecnologia, Brazil, SIM |
| INPL |
National Physical Laboratory of Israel, Israel, N/A |
| NMIJ AIST |
National Metrology Institute of Japan, Japan, APMP |
| SMU |
Slovensky Metrologicky Ustav, Slovakia, EURAMET |
| UkrCSM |
Ukrmetrteststandard, Ukraine, EURAMET |
| VNIIFTRI |
Institute of Physical Technical and Radiotechnical Measurements, Rosstandart, Russian Federation, COOMET |
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 : pH value of tetroxalate buffer
Measurements at 15 °C
NOMINAL VALUE : pH ~ 1.7
|
The key comparison reference value, pa0R, is obtained as the weighted mean of the results from the participants excluding INPL and VNIIFTRI measurement results. The standard uncertainty, uR, of pa0R is calculated according to the external consistency method (see page 11 of CCQM-K20 Final Report). pa0R = 1.7833 and uR = 0.0010 |
| The degree of equivalence of each laboratory with respect to the key comparison reference value is given by a pair of terms: Di = (pa0i - pa0R) and Ui, its expanded uncertainty (k = 2), Ui = 2(ui2 + uR2)1/2. |
| No pair-wise degrees of equivalence are calculated for this comparison. |
MEASURAND : pH value of tetroxalate buffer
Measurements at 25 °C
NOMINAL VALUE : pH ~ 1.7
|
The key comparison reference value, pa0R, is obtained as the weighted mean of the results from the participants excluding INPL and VNIIFTRI measurement results. The standard uncertainty, uR, of pa0R is calculated according to the external consistency method (see page 11 of CCQM-K20 Final Report). pa0R = 1.79223 and uR = 0.00078 |
| The degree of equivalence of each laboratory with respect to the key comparison reference value is given by a pair of terms: Di = (pa0i - pa0R) and Ui, its expanded uncertainty (k = 2), Ui = 2(ui2 + uR2)1/2. |
| No pair-wise degrees of equivalence are calculated for this comparison. |
MEASURAND : pH value of tetroxalate buffer
Measurements at 37 °C
NOMINAL VALUE : pH ~ 1.7
|
The key comparison reference value, pa0R, is obtained as the weighted mean of the results from the participants excluding INPL and VNIIFTRI measurement results. The standard uncertainty, uR, of pa0R is calculated according to the external consistency method (see page 11 of CCQM-K20 Final Report). pa0R = 1.80634 and uR = 0.00067 |
| The degree of equivalence of each laboratory with respect to the key comparison reference value is given by a pair of terms: Di = (pa0i - pa0R) and Ui, its expanded uncertainty (k = 2), Ui = 2(ui2 + uR2)1/2. |
| No pair-wise degrees of equivalence are calculated for this comparison. |
MEASURAND : pH value of tetroxalate buffer
Measurements at 15 °C
NOMINAL VALUE : pH ~ 1.7
pa0i : result of measurement carried out by laboratory i reported as the extrapolation of the acidity function at zero chloride molality of an unknown tetroxalate buffer
ui : combined standard uncertainty (k = 1) of pa0i
ULab i : expanded uncertainty (k = 2) of pa0i, ULab i = 2ui
|
Lab i |
pa0i | ULab i | Date of measurement |
| CENAM | 1.7808 | 0.0058 | Oct - Nov 07 |
| CMI | 1.7827 | 0.0041 | Nov - Dec 07 |
| DFM | 1.7816 | 0.0029 | Oct - Nov 07 |
| GUM | 1.7889 | 0.0038 | Oct - Nov 07 |
| INMETRO | 1.7718 | 0.0029 | Dec 07 |
| INPL | 1.8141 | 0.0082 | Dec 07 |
| BIM |
- |
- |
- |
| BIM revised* | - | - | - |
| NIST | 1.78423 | 0.00077 | Dec 07 |
| NMIJ | 1.7844 | 0.0022 | Nov 07 |
| SMU | 1.7818 | 0.0020 | Sep 07 |
| UkrCSM | 1.7828 | 0.0038 | Oct 07 |
| VNIIFTRI |
1.7838 |
- |
Dec 07 |
* See on page 6 of the CCQM-K20 Final Report
MEASURAND : pH value of tetroxalate buffer
Measurements at 25 °C
NOMINAL VALUE : pH ~ 1.7
pa0i : result of measurement carried out by laboratory i reported as the extrapolation of the acidity function at zero chloride molality of an unknown tetroxalate buffer
ui : combined standard uncertainty (k = 1) of pa0i
ULab i : expanded uncertainty (k = 2) of pa0i, ULab i = 2ui
|
Lab i |
pa0i | ULab i | Date of measurement |
| CENAM | 1.7918 | 0.0051 | Oct - Nov 07 |
| CMI | 1.7933 | 0.0045 | Nov - Dec 07 |
| DFM | 1.7911 | 0.0028 | Oct - Nov 07 |
| GUM | 1.7990 | 0.0038 | Oct - Nov 07 |
| INMETRO | 1.7867 | 0.0056 | Dec 07 |
| INPL | 1.8222 | 0.0078 | Dec 07 |
| BIM |
1.7788 |
0.0044 |
Nov 07 |
| BIM revised* | 1.7825 | 0.0044 | Nov 07 |
| NIST | 1.7928 | 0.0010 | Dec 07 |
| NMIJ | 1.7934 | 0.0022 | Nov 07 |
| SMU | 1.7917 | 0.0020 | Sep 07 |
| UkrCSM | 1.7897 | 0.0028 | Oct 07 |
| VNIIFTRI |
1.7915 |
- |
Dec 07 |
* See on page 6 of the CCQM-K20 Final Report
MEASURAND : pH value of tetroxalate buffer
Measurements at 37 °C
NOMINAL VALUE : pH ~ 1.7
pa0i : result of measurement carried out by laboratory i reported as the extrapolation of the acidity function at zero chloride molality of an unknown tetroxalate buffer
ui : combined standard uncertainty (k = 1) of pa0i
ULab i : expanded uncertainty (k = 2) of pa0i, ULab i = 2ui
|
Lab i |
pa0i | ULab i | Date of measurement |
| CENAM | 1.8050 | 0.0024 | Oct - Nov 07 |
| CMI | 1.8074 | 0.0039 | Nov - Dec 07 |
| DFM | 1.8078 | 0.0043 | Oct - Nov 07 |
| GUM | 1.8133 | 0.0044 | Oct - Nov 07 |
| INMETRO | 1.7995 | 0.0061 | Dec 07 |
| INPL | 1.8345 | 0.0079 | Dec 07 |
| BIM |
1.8001 |
0.0046 |
Nov 07 |
| BIM revised* | 1.8035 | 0.0046 | Nov 07 |
| NIST | 1.8061 | 0.0014 | Dec 07 |
| NMIJ | 1.8077 | 0.0022 | Nov 07 |
| SMU | 1.8068 | 0.0020 | Sep 07 |
| UkrCSM | 1.8035 | 0.0032 | Oct 07 |
| VNIIFTRI |
1.8057 |
- |
Dec 07 |
* See on page 6 of the CCQM-K20 Final Report
