CCQM-K99
MEASURAND : pH value of an unknown phosphate buffer
Measurements at 15 °C, 25 °C, 37 °C. Optional: 5 °C and 50 °C.
NOMINAL VALUE : pH = 7.5
Degrees of equivalence Di and expanded uncertainty Ui (k = 2)
CCQM-K99
MEASURAND : pH value of an unknown phosphate buffer
Measurements at 15 °C, 25 °C, 37 °C. Optional: 5 °C and 50 °C.
NOMINAL VALUE : pH = 7.5
Degrees of equivalence Di and expanded uncertainty Ui (k = 2)
A printable Summary of Resuts is available in A4 format.
| Metrology area, Sub-field | Chemistry and Biology, Electrochemistry |
| Description | pH of phosphate buffer |
| Time of measurements | 2014 |
| Status | Approved for equivalence |
| Final Reports of the comparisons | |
| Measurand | pH ~ 7.5 |
| Transfer device | Dedicated samples |
| 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 4 January 2016 pH of an unknown phosphate buffer
|
| Pilot institute |
PTB
Physikalisch-Technische Bundesanstalt Germany |
| Contact person | Frank Bastkowski |
| Pilot laboratory | |
|---|---|
| PTB |
Physikalisch-Technische Bundesanstalt, Germany, EURAMET |
| 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 |
| IBMETRO |
Instituto Boliviano de Metrología, Bolivia, SIM |
| INDECOPI |
Instituto Nacional de Defensa de la Competencia y de la Protección de la Propiedad Intelectual, Peru, SIM |
| INMETRO |
Instituto Nacional de Metrologia, Qualidade e Tecnologia, Brazil, SIM |
| LATU |
Laboratorio Tecnologico del Uruguay, Uruguay, SIM |
| MKEH |
Hungarian Trade Licensing Office; now BFKH, Hungary, EURAMET |
| NIMT |
National Institute of Metrology (Thailand), Thailand, APMP |
| NIST |
National Institute of Standards and Technology, United States, SIM |
| NMIJ AIST |
National Metrology Institute of Japan, Japan, APMP |
| SE "Ukrmetrteststandard" |
State Enterprise "Ukrmetrteststandard", Ukraine, EURAMET |
| SMU |
Slovensky Metrologicky Ustav, Slovakia, EURAMET |
| UME |
TÜBITAK Ulusal Metroloji Enstitüsü, Türkiye, 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" :
CCQM-K99
MEASURAND : pH value of an unknown phosphate buffer
Measurements at 15 °C, 25 °C, 37 °C. Optional: 5 °C and 50 °C.
NOMINAL VALUE : pH = 7.5
|
The key comparison reference value, pHR, is obtained by calculating the weighted mean including the institutes using primary standards for which the results passed a previously defined consistancy filter. t = 15 °C : pHR = 7.5561 and uR = 0.0009 t = 25 °C : pHR = 7.5246 and uR = 0.0008 t = 37 °C : pHR = 7.5013 and uR = 0.0009 t = 5 °C : pHR = 7.6043 and uR = 0.0015 t = 50 °C : pHR = 7.4960 and uR = 0.0029 |
| The degree of equivalence of each laboratory with respect to the key comparison reference value is given by a pair of terms: Di = (pHi - pHR) and Ui, its expanded uncertainty (k = 2), Ui = 2((1 - 2wi) ui2 + uR2)1/2, where wi represents the weight of laboratory i. |
CCQM-K99
MEASURAND : pH value of an unknown phosphate buffer
Measurements at 15 °C, 25 °C, 37 °C. Optional: 5 °C and 50 °C.
NOMINAL VALUE : pH = 7.5
pHi : result of measurement carried out by laboratory i
ui : combined standard uncertainty (k = 1) of pHi
