CCQM-K91, SIM.QM-K91 and APMP.QM-K91
MEASURAND : Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer
Sample: Potassium hydrogen phthalate, KHC8H4O4
Measurements at 15 °C
NOMINAL VALUE : pH ~ 4.01 at 25 °C
Degrees of equivalence, Di and expanded uncertainty Ui (k = 2)
CCQM-K91, SIM.QM-K91 and APMP.QM-K91
MEASURAND : Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer
Sample: Potassium hydrogen phthalate, KHC8H4O4
Measurements at 25 °C
NOMINAL VALUE : pH ~ 4.01 at 25 °C
Degrees of equivalence, Di and expanded uncertainty Ui (k = 2)
CCQM-K91, SIM.QM-K91 and APMP.QM-K91
MEASURAND : Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer
Sample: Potassium hydrogen phthalate, KHC8H4O4
Measurements at 37 °C
NOMINAL VALUE : pH ~ 4.01 at 25 °C
Degrees of equivalence, Di and expanded uncertainty Ui (k = 2)
CCQM-K91, SIM.QM-K91 and APMP.QM-K91
MEASURAND : Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer
Sample: Potassium hydrogen phthalate, KHC8H4O4
Measurements at 15 °C
NOMINAL VALUE : pH ~ 4.01 at 25 °C
Degrees of equivalence, Di and expanded uncertainty Ui (k = 2)
| LABi | Di | Uneg,i | Upos,i | |
|---|---|---|---|---|
dimensionless |
dimensionless |
dimensionless |
||
| BIM (revised) | -0.0036 | 0.0081 | ||
| BIM (original) | -0.0102 | 0.0081 | ||
| INMETRO | -0.0022 | 0.0032 | ||
| DFM | 0.0004 | 0.0016 | ||
| PTB | 0.0010 | 0.0026 | ||
| LNE | -0.0018 | 0.0045 | ||
| NMIJ | 0.0001 | 0.0026 | ||
| MKEH | -0.0006 | 0.0030 | ||
| CENAM | -0.0045 | 0.0023 | ||
| GUM | -0.0001 | 0.0030 | ||
| VNIIFTRI | 0.0003 | 0.0061 | ||
| SMU | 0.0009 | 0.0023 | ||
| NIMT | -0.0038 | 0.0051 | ||
| NIST | 0.0014 | 0.0016 | ||
| INDECOPI | 0.0024 | 0.0041 | ||
| BIM | -0.0019 | 0.0079 | ||
| INDECOPI | 0.0004 | 0.0076 | ||
| NIMT | -0.0111 | 0.0096 | ||
| SE "Ukrmetrteststandard" | -0.0320 | 0.0088 | ||
| LATU | 0.0000 | 0.0122 | ||
| RCChem-LIPI | -0.0003 | 0.0032 | ||
| VMI-STAMEQ | 0.0127 | 0.0106 | ||
| CMI | -0.0013 | 0.0042 | ||
| VNIIFTRI | -0.0025 | 0.0046 | ||
| UME | 0.0218 | 0.0060 | ||
| CENAM | -0.0045 | 0.0142 | ||
| INACAL | -0.0005 | 0.0040 | ||
| NMIM | -0.0020 | 0.0064 | ||
| BelGIM | -0.0103 | 0.0068 | ||
| GL | -0.0003 | 0.0144 |
CCQM-K91, SIM.QM-K91 and APMP.QM-K91
MEASURAND : Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer
Sample: Potassium hydrogen phthalate, KHC8H4O4
Measurements at 25 °C
NOMINAL VALUE : pH ~ 4.01 at 25 °C
Degrees of equivalence, Di and expanded uncertainty Ui (k = 2)
| LABi | Di | Uneg,i | Upos,i | |
|---|---|---|---|---|
dimensionless |
dimensionless |
dimensionless |
||
| BIM (revised) | -0.0028 | 0.0080 | ||
| BIM (original) | -0.0104 | 0.0080 | ||
| INMETRO | -0.0017 | 0.0024 | ||
| DFM | 0.0005 | 0.0013 | ||
| PTB | 0.0006 | 0.0025 | ||
| LNE | -0.0014 | 0.0037 | ||
| NMIJ | -0.0004 | 0.0025 | ||
| MKEH | 0.0012 | 0.0029 | ||
| CENAM | -0.0031 | 0.0024 | ||
| GUM | -0.0009 | 0.0033 | ||
| VNIIFTRI | 0.0007 | 0.0074 | ||
| SMU | 0.0011 | 0.0022 | ||
| NIMT | -0.0052 | 0.0051 | ||
| NIST | 0.0011 | 0.0018 | ||
| INDECOPI | -0.0012 | 0.0041 | ||
| BIM | -0.0019 | 0.0055 | ||
| IBMETRO | -0.0045 | 0.0054 | ||
| INM (CO) | 0.0008 | 0.0063 | ||
| INDECOPI | -0.0020 | 0.0047 | ||
| NIMT | -0.0119 | 0.0051 | ||
| SE "Ukrmetrteststandard" | -0.0347 | 0.0052 | ||
| LATU | -0.0004 | 0.0106 | ||
| RCChem-LIPI | -0.0015 | 0.0030 | ||
| VMI-STAMEQ | 0.0204 | 0.0104 | ||
| CMI | 0.0021 | 0.0076 | ||
| VNIIFTRI | 0.0001 | 0.0046 | ||
| UME | 0.0217 | 0.0038 | ||
| CENAM | -0.0094 | 0.0098 | ||
| INACAL | -0.0019 | 0.0038 | ||
| NMIM* | 0.0009 | 0.0068 | ||
| BelGIM | -0.0073 | 0.0048 | ||
| GL | -0.0015 | 0.0132 |
CCQM-K91, SIM.QM-K91 and APMP.QM-K91
MEASURAND : Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer
Sample: Potassium hydrogen phthalate, KHC8H4O4
Measurements at 37 °C
NOMINAL VALUE : pH ~ 4.01 at 25 °C
Degrees of equivalence, Di and expanded uncertainty Ui (k = 2)
| LABi | Di | Uneg,i | Upos,i | |
|---|---|---|---|---|
dimensionless |
dimensionless |
dimensionless |
||
| BIM (revised) | -0.0014 | 0.0081 | ||
| BIM (original) | -0.0089 | 0.0081 | ||
| INMETRO | -0.0016 | 0.0025 | ||
| DFM | 0.0010 | 0.0014 | ||
| PTB | -0.0004 | 0.0026 | ||
| LNE | -0.0035 | 0.0041 | ||
| NMIJ | 0.0004 | 0.0031 | ||
| MKEH | -0.0045 | 0.0061 | ||
| CENAM | -0.0014 | 0.0026 | ||
| GUM | -0.0031 | 0.0029 | ||
| VNIIFTRI | -0.0010 | 0.0081 | ||
| SMU | 0.0015 | 0.0022 | ||
| NIMT | -0.0033 | 0.0081 | ||
| NIST | 0.0006 | 0.0039 | ||
| INDECOPI | -0.0012 | 0.0041 | ||
| BIM | -0.0039 | 0.0040 | ||
| INDECOPI | -0.0038 | 0.0032 | ||
| NIMT | 0.0235 | 0.0077 | ||
| SE "Ukrmetrteststandard" | -0.0461 | 0.0040 | ||
| LATU | -0.0015 | 0.0101 | ||
| RCChem-LIPI | -0.0002 | 0.0032 | ||
| VMI-STAMEQ | 0.0858 | 0.0104 | ||
| CMI | -0.0025 | 0.0046 | ||
| VNIIFTRI | 0.0013 | 0.0044 | ||
| UME | 0.0198 | 0.0062 | ||
| CENAM | 0.0048 | 0.0170 | ||
| INACAL | 0.0000 | 0.0048 | ||
| NMIM* | -0.0154 | 0.0062 | ||
| BelGIM | -0.0109 | 0.0070 | ||
| GL | -0.0022 | 0.0118 |
| Metrology area, Sub-field | Chemistry and Biology, Electrochemistry |
| Description | pH measurement of an unknown phthalate buffer |
| Time of measurements | 2015 |
| Status | Approved for equivalence |
| Final Reports of the comparisons | |
| Measurand | pH ~ 4 |
| Comparison type | Key Comparison |
| Consultative Committee | CCQM (Consultative Committee for Amount of Substance) |
| Conducted by | APMP (Asia Pacific Metrology Programme) |
| Comments | Results published on 13 december 2016 SIM.QM-K91 and APMP.QM-K91 results are linked to those of CCQM-K91 pH determination of a phthalate buffer
|
| Pilot institute |
NMIJ AIST
National Metrology Institute of Japan Japan |
| Contact person | A. Hioki +81 29 861 9341 |
| Pilot laboratory | |
|---|---|
| NMIJ AIST |
National Metrology Institute of Japan, Japan, APMP |
| BelGIM |
Belarussian State Institute for Metrology, Belarus, COOMET |
| CENAM |
Centro Nacional de Metrologia, Mexico, SIM |
| CMI |
Czech Metrology Institute, Czechia, EURAMET |
| GL |
Government Laboratory, Hong Kong, China, APMP |
| INACAL |
National Institute for Quality, Peru, SIM |
| NMIM |
National Metrology Institute of Malaysia, Malaysia, APMP |
| PTB |
Physikalisch-Technische Bundesanstalt, Germany, EURAMET |
| UME |
TÜBITAK Ulusal Metroloji Enstitüsü, Türkiye, EURAMET |
| VMI-STAMEQ |
Viet Nam Metrology Institute, Directorate for Standards and Quality, Viet Nam, APMP |
| VNIIFTRI |
Institute of Physical Technical and Radiotechnical Measurements, Rosstandart, Russian Federation, COOMET |
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CCQM-K91, SIM.QM-K91 and APMP.QM-K91
MEASURAND : Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer
Sample: Potassium hydrogen phthalate, KHC8H4O4
Measurements at 15 °C
NOMINAL VALUE : pH ~ 4.01 at 25 °C
| The key comparison reference value, xR, is calculated as the weighted mean of the participants' results excluding those from BIM, INDECOPI, UME, and, SE "Ukrmetrteststandard". The standard uncertainty, uR, of xR is calculated according to the external consistency method (see page 15 of the Final Report). |
pa0R = 4.0853 and UR = 2uR = 0.0011
|
The degree of equivalence of laboratory i with respect to the key comparison reference value is given by a pair of terms: Di = (xi - xR) and Ui, its expanded uncertainty (k = 2), |
| There are no pair-wise degrees of equivalence computed for this key comparison. |
The common participation of INMETRO and NIST in two key comparisons makes it possible to compute the linkage of the results, as explained on pages 10 and 11 of the SIM.QM-K91 Final Report.
The common participation of NMIJ and PTB in two key comparisons makes it possible to compute the linkage of the results.
CCQM-K91, SIM.QM-K91 and APMP.QM-K91
MEASURAND : Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer
Sample: Potassium hydrogen phthalate, KHC8H4O4
Measurements at 25 °C
NOMINAL VALUE : pH ~ 4.01 at 25 °C
| The key comparison reference value, xR, is calculated as the weighted mean of the participants' results excluding those from BIM, Indecopi, UME, and, SE "Ukrmetrteststandard". The standard uncertainty, uR, of xR is calculated according to the external consistency method (see page 15 of the Final Report). |
pa0R = 4.0935 and UR = 2uR = 0.00083
|
The degree of equivalence of laboratory i with respect to the key comparison reference value is given by a pair of terms: Di = (xi - xR) and Ui, its expanded uncertainty (k = 2), |
| There are no pair-wise degrees of equivalence computed for this key comparison. |
The common participation of INMETRO and NIST in two key comparisons makes it possible to compute the linkage of the results, as explained on pages 10 and 11 of the SIM.QM-K91 Final Report.
The common participation of NMIJ and PTB in two key comparisons makes it possible to compute the linkage of the results.
CCQM-K91, SIM.QM-K91 and APMP.QM-K91
MEASURAND : Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer
Sample: Potassium hydrogen phthalate, KHC8H4O4
Measurements at 37 °C
NOMINAL VALUE : pH ~ 4.01 at 25 °C
| The key comparison reference value, xR, is calculated as the weighted mean of the participants' results excluding those from BIM, Indecopi, UME, and, SE "Ukrmetrteststandard". The standard uncertainty, uR, of xR is calculated according to the external consistency method (see page 15 of the Final Report). |
pa0R = 4.1147 and UR = 2uR = 0.00092
|
The degree of equivalence of laboratory i with respect to the key comparison reference value is given by a pair of terms: Di = (xi - xR) and Ui, its expanded uncertainty (k = 2), |
| There are no pair-wise degrees of equivalence computed for this key comparison. |
The common participation of INMETRO and NIST in two key comparisons makes it possible to compute the linkage of the results, as explained on pages 10 and 11 of the SIM.QM-K91 Final Report.
The common participation of NMIJ and PTB in two key comparisons makes it possible to compute the linkage of the results.
CCQM-K91, SIM.QM-K91 and APMP.QM-K91
MEASURAND : Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer
Sample: Potassium hydrogen phthalate, KHC8H4O4
Measurements at 15 °C
NOMINAL VALUE : pH ~ 4.01 at 25 °C
xi : result of measurement carried out by laboratory i
ULabi : expanded uncertainty (k = 2) of xi; ULabi = 2ui
* BIM observed a calculation error in the standard potential E0 and sent revised pa0 values one month after the comparison deadline.
**INDECOPI used a secondary measurement method.
***UME and SE "Ukrmetrteststandard" reported problems with their measurements (see page 9 of the Final Report).
xi : result of measurement carried out by laboratory i
ui : combined standard uncertainty of xi
xi : result of measurement carried out by laboratory i
ui : combined standard uncertainty of xi
NMIM, formerly known as NRL-SIRIM
CCQM-K91, SIM.QM-K91 and APMP.QM-K91
MEASURAND : Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer
Sample: Potassium hydrogen phthalate, KHC8H4O4
Measurements at 25 °C
NOMINAL VALUE : pH ~ 4.01 at 25 °C
xi : result of measurement carried out by laboratory i
ULabi : expanded uncertainty (k = 2) of xi; ULabi = 2ui
* BIM observed a calculation error in the standard potential E0 and sent revised pa0 values one month after the comparison deadline.
**INDECOPI used a secondary measurement method.
***UME and SE "Ukrmetrteststandard" reported problems with their measurements (see page 9 of the Final Report).
xi : result of measurement carried out by laboratory i
ui : combined standard uncertainty of xi
ul>
xi : result of measurement carried out by laboratory i
ui : combined standard uncertainty of xi
NMIM, formerly known as NRL-SIRIM
CCQM-K91, SIM.QM-K91 and APMP.QM-K91
MEASURAND : Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer
Sample: Potassium hydrogen phthalate, KHC8H4O4
Measurements at 37 °C
NOMINAL VALUE : pH ~ 4.01 at 25 °C
xi : result of measurement carried out by laboratory i
ULabi : expanded uncertainty (k = 2) of xi; ULabi = 2ui
* BIM observed a calculation error in the standard potential E0 and sent revised pa0 values one month after the comparison deadline.
**Indecopi used a secondary measurement method.
***UME and SE "Ukrmetrteststandard" reported problems with their measurements (see page 9 of the Final Report).
xi : result of measurement carried out by laboratory i
ui : combined standard uncertainty of xi
xi : result of measurement carried out by laboratory i
ui : combined standard uncertainty of xi
NMIM, formerly known as NRL-SIRIM
