Comparison
Comparison close
Results

CCQM-K18 and CCQM-K18.1

MEASURAND : Acidity function at zero chloride molality of a carbonate buffer
pH ~ 10

TEMPERATURE : 25 °C

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

Red diamonds : participants in CCQM-K18
Green triangles : participants in CCQM-K18.1

In CCQM-K18: DINPL = 0.0663 and UINPL = 0.0105

Open symbols represent values for laboratories in Associate States and Economies of the CGPM

Comparison
Comparison close
Results

CCQM-K18 and CCQM-K18.1

MEASURAND : Acidity function at zero chloride molality of a carbonate buffer
pH ~ 10

TEMPERATURE : 25 °C

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

* participation in CCQM-K18.1

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

Comparison
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CC comparison
Linked comparison
CCQM-K18.1
Metrology area, Sub-field Chemistry and Biology, Electrochemistry
Description pH measurement of carbonate buffer solutions
Time of measurements 2007
Status Approved for equivalence
Final Reports of the comparisons
Measurand pH 10
Parameters Temperature: 25 °C
Transfer device Carbonate 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

This is a follow-up to key comparison CCQM-K18.

Results published on 29 September 2008

CCQM-K18.1 results are linked to those of CCQM-K18

pH of a carbonate buffer

Pilot institute SMU
Slovensky Metrologicky Ustav
Slovakia
Contact person L. Vyskocil

+421 2 602 94 225
First Name Last Name
wwww@ww.www +356719836 Institute 1 Institute 1 Khmelnitskiy
Pilot laboratory
SMU

Slovensky Metrologicky Ustav, Slovakia, EURAMET

CENAM

Centro Nacional de Metrologia, Mexico, SIM

DFM

Danish Fundamental Metrology A/S, Denmark, EURAMET

INMETRO

Instituto Nacional de Metrologia, Qualidade e Tecnologia, Brazil, SIM

INPL

National Physical Laboratory of Israel, Israel, N/A

LNE

Laboratoire national de métrologie et d'essais, France, EURAMET

NIM

National Institute of Metrology, China, APMP

PTB

Physikalisch-Technische Bundesanstalt, Germany, EURAMET

Comparison
Comparison close
Results

CCQM-K18 and CCQM-K18.1

MEASURAND : Acidity function at zero chloride molality of a carbonate buffer
pH ~ 10

TEMPERATURE : 25 °C

  • Key comparison CCQM-K18

The key comparison reference value, xR, is computed as the median of results of all participants except INPL. Its standard uncertainty, uR, is the standard uncertainty of the median.

xR = 10.1985 and uR = 0.0019

The degree of equivalence of each 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), Ui = 2(ui2 + uR2)1/2.

The degree of equivalence between two laboratories i and j is given by a pair of terms: Dij = Di - Dj = xi - xj and Uij, its expanded uncertainty (k = 2),
Uij = 2(ui2 + uj2)1/2.
No pair-wise degrees of equivalence are explicitely computed.
  • Linking CCQM-K18.1 to CCQM-K18

SMU provides the linkage between both key comparisons, as explained on page 9 of the CCQM-K18.1 Final Report.

The degree of equivalence of each laboratory i participant in CCQM-K18.1 with respect to the CCQM-K18 key comparison reference value is given by a pair of terms:
Di = DSMU (K18) + xi (K18.1) - xSMU (K18.1) and Ui, its expanded uncertainty (k = 2), Ui = [USMU (K18)2 + [2ui (K18.1)]2 + [2uSMU (K18.1)]2]1/2.

No pair-wise degrees of equivalence are explicitely computed.
Comparison
Comparison close
Results

CCQM-K18 and CCQM-K18.1

  • Key comparison CCQM-K18

MEASURAND : Acidity function at zero chloride molality of a carbonate buffer
pH ~ 10

TEMPERATURE : 25 °C

xi : result of measurement carried out by laboratory i
ui : combined standard uncertainty (k = 1) of xi

 Lab i

xi ui Date of
measurement
 NIM 10.1815 0.0018 Aug - Sep 06
 LNE 10.1852 0.0036 Aug 06
 NCM 10.1945 0.0037 Sep 06
 NIST 10.1969 0.0008 Sep 06
 GUM 10.1975 0.0017 Sep 06
 UkrCSM 10.1975 0.0030 Sep 06
 SMU 10.1995 0.0015 Aug 06
 CMI 10.2003 0.0012 Sep - Oct 06
 NMIJ 10.2014 0.0013 Aug 06
 INMETRO 10.2051 0.0032 Oct 06
 CENAM 10.2102 0.0011 Sep 06
 PTB

10.2107

0.0015

Aug - Sep 06

 INPL

10.2648

0.0049

Sep 06

  • Key comparison CCQM-K18.1

MEASURAND : Acidity function at zero chloride molality of a carbonate buffer
pH ~ 10

TEMPERATURE : 25 °C

xi (K18.1) : result of measurement carried out by laboratory i
ui (K18.1) : combined standard uncertainty (k = 1) of xi

 Lab i

xi (K18.1) ui (K18.1) Date of
measurement
 LNE 10.0857 0.0034 Jul 07
 NIM 10.0861 0.0018 Jul 07
 INMETRO 10.1032 0.0016 Jul 07
 SMU 10.1033 0.0015 Jul 07
 PTB 10.1048 0.0015 Jul 07
 DFM 10.1076 0.0006 Jul 07
 CENAM 10.1092 0.0018 Jul 07
 INPL 10.1409 0.0033 Jul 07