CCQM-K91.2022

MEASURAND:   Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer

SAMPLE:                   Potassium hydrogen phthalate in deionized water

Measurements at 15 °C

NOMINAL VALUE: pH ~ 4.0

 

Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui at a 95 % level of confidence.

Acidity Function at zero chloride molality measured at 15 °C
Di / dimensionless
Participating institutes

Enlarged graph

Graph@15Deg

CCQM-K91.2022

MEASURAND:   Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer

SAMPLE:                   Potassium hydrogen phthalate in deionized water

Measurements at 25 °C

NOMINAL VALUE: pH ~ 4.0

 

Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui at a 95 % level of confidence.

Acidity Function at zero chloride molality measured at 25 °C
Di / dimensionless
Participating institutes

Enlarged graph

Graph@25Deg

CCQM-K91.2022

MEASURAND:   Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer

SAMPLE:                   Potassium hydrogen phthalate in deionized water

Measurements at 37 °C

NOMINAL VALUE: pH ~ 4.0

 

Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui at a 95 % level of confidence.

Acidity Function at zero chloride molality measured at 37 °C
Di / dimensionless
Participating institutes

Enlarged graph

Graph@37Deg

CCQM-K91.2022

MEASURAND:   Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer

SAMPLE:                   Potassium hydrogen phthalate in deionized water

Measurements at 15 °C

NOMINAL VALUE: pH ~ 4.0

 

Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui at a 95 % level of confidence.

LABi Di Uneg,i Upos,i
dimensionless
dimensionless
dimensionless
BFKH -0.0020 0.0055
BIM -0.0039 0.0042
CENAM -0.0043 0.0346
CMI 0.0003 0.0019
INMETRO 0.0034 0.0023
NIM -0.0028 0.0034
NMIJ -0.0006 0.0025
VNIIFTRI -0.0004 0.0034
Participating institutes
CCQM-K91.2022

CCQM-K91.2022

MEASURAND:   Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer

SAMPLE:                   Potassium hydrogen phthalate in deionized water

Measurements at 25 °C

NOMINAL VALUE: pH ~ 4.0

 

Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui at a 95 % level of confidence.

LABi Di Uneg,i Upos,i
dimensionless
dimensionless
dimensionless
BFKH 0.0001 0.0047
BIM -0.0005 0.0043
SNSU-BSN -0.0041 0.0047
CENAM 0.0076 0.0266
CMI -0.0002 0.0017
IBMETRO -0.0049 0.0103
INMETRO 0.0033 0.0024
INTI 0.0190 0.0360
LATU 0.0010 0.0034
NIM -0.0025 0.0034
NMIJ -0.0008 0.0024
UME -0.0032 0.0057
VNIIFTRI -0.0004 0.0032
Participating institutes
CCQM-K91.2022

 

 

CCQM-K91.2022

MEASURAND:   Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer

SAMPLE:                   Potassium hydrogen phthalate in deionized water

Measurements at 37 °C

NOMINAL VALUE: pH ~ 4.0

 

Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui at a 95 % level of confidence.

LABi Di Uneg,i Upos,i
dimensionless
dimensionless
dimensionless
BFKH -0.0003 0.0053
BIM 0.0023 0.0043
CENAM 0.0418 0.0342
CMI -0.0001 0.0014
INMETRO 0.0017 0.0028
NIM -0.0027 0.0034
NMIJ -0.0004 0.0023
VNIIFTRI -0.0001 0.0034
Participating institutes
CCQM-K91.2022
Comparison
Comparison close
CC comparison
Linked comparison
EURAMET.QM-K91.2022
Metrology area, Sub-field Chemistry and Biology, Electrochemistry
Description Acidity function of an unknown phthalate buffer at zero chloride molality
Time of measurements 2025 - 2026
Status Planned
Measurand Acidity function at zero chloride molality, pa0
Nominal value of pH ~4.01 at temperature 25 °C
Parameters Temperature: 15 °C, 25 °C and 37 °C, and optional at 5 °C and 50 °C
Measurement by Harned cell and differential potentiometric
Transfer device Aqueous phthalate buffer
Comparison type Key Comparison
Consultative Committee CCQM (Consultative Committee for Amount of Substance)
Conducted by EURAMET (European Association of National Metrology Institutes)
Pilot institute CMI
Czech Metrology Institute
Czechia
Contact person Matilda Rozikova

+420 545 555 321
First Name Last Name
wwww@ww.www +356719836 Institute 1 Institute 1 Khmelnitskiy
Pilot laboratory
CMI

Czech Metrology Institute, Czechia, EURAMET

CCQM-K91.2022

MEASURAND:   Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer

SAMPLE:                   Potassium hydrogen phthalate in deionized water

Measurements at 15 °C

NOMINAL VALUE: pH ~ 4.0

 

The key comparison reference value xR and its associated standard uncertainty uR are computed from the weighted mean uncorrected for observed dispersion according to equation 7 to 9 of the CCQM-K91.2022 Final report, from results obtained using primary method CENAM excluded.

 

        xR = 4.0873     uR = 0.0006

 

The degree of equivalence of laboratory i relative to the key comparison reference value xR is given by a pair of terms:

Di = (xi - xR) and its expanded uncertainty Ui at a 95 % level of confidence where Ui = 2 (u2 - uR2)1/2 for resuts used in calculation of xR and

Ui = 2(u2 + uR2)1/2 for results not used in the calculation of xR.

CCQM-K91.2022

MEASURAND:   Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer

SAMPLE:                   Potassium hydrogen phthalate in deionized water

Measurements at 25 °C

NOMINAL VALUE: pH ~ 4.0

 

The key comparison reference value xR and its associated standard uncertainty uR are computed from the weighted mean uncorrected for observed dispersion according to equation 7 to 9 of the CCQM-K91.2022 Final report, from results obtained using primary method CENAM excluded.

 

        xR = 4.0956     uR = 0.0005

 

The degree of equivalence of laboratory i relative to the key comparison reference value xR is given by a pair of terms:

Di = (xi - xR) and its expanded uncertainty Ui at a 95 % level of confidence where Ui = 2 (u2 - uR2)1/2 for resuts used in calculation of xR and

Ui = 2(u2 + uR2)1/2 for results not used in the calculation of xR.

CCQM-K91.2022

MEASURAND:   Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer

SAMPLE:                   Potassium hydrogen phthalate in deionized water

Measurements at 37 °C

NOMINAL VALUE: pH ~ 4.0

 

The key comparison reference value xR and its associated standard uncertainty uR are computed from the weighted mean uncorrected for observed dispersion according to equation 7 to 9 of the CCQM-K91.2022 Final report, from results obtained using primary method CENAM excluded.

 

        xR = 4.1159     uR = 0.0006

 

The degree of equivalence of laboratory i relative to the key comparison reference value xR is given by a pair of terms:

Di = (xi - xR) and its expanded uncertainty Ui at a 95 % level of confidence where Ui = 2 (u2 - uR2)1/2 for resuts used in calculation of xR and

Ui = 2(u2 + uR2)1/2 for results not used in the calculation of xR.

CCQM-K91.2022

MEASURAND:   Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer

SAMPLE:                   Potassium hydrogen phthalate in deionized water

Measurements at 15 °C

NOMINAL VALUE: pH ~ 4.0

 

xi   measured mass fraction reported by laboratory iLabi

ui   combined standard uncertainty of xi

  Labi xi ui
  dimensionless dimensionless
  BFKH 4.0853 0.0028
  BIM 4.0834 0.0022
  CENAM 4.0830 0.0173
  CMI 4.0876 0.0011
  INMETRO 4.0907 0.0013
  NIM 4.0845 0.0018
  NMIJ 4.0867 0.0014
  VNIIFTRI 4.0869 0.0018

CCQM-K91.2022

MEASURAND:   Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer

SAMPLE:                   Potassium hydrogen phthalate in deionized water

Measurements at 25 °C

NOMINAL VALUE: pH ~ 4.0

 

xi   measured mass fraction reported by laboratory iLabi

ui   combined standard uncertainty of xi

  Labi xi ui
  dimensionless dimensionless
  BFKH 4.0957 0.0024
  BIM 4.0951 0.0022
  SNSU-BSN 4.0915 0.0023
  CENAM 4.1032 0.0133
  CMI 4.0954 0.0010
  IBMETRO 4.0907 0.0051
  INMETRO 4.0989 0.0013
  INTI 4.1146 0.0180
  LATU 4.0966 0.0016
  NIM 4.0931 0.0018
  NMIJ 4.0948 0.0013
  UME 4.0924 0.0029
  VNIIFTRI 4.0952 0.0017

CCQM-K91.2022

MEASURAND:   Acidity function at zero chloride molality, pa0, of an unknown phthalate buffer

SAMPLE:                   Potassium hydrogen phthalate in deionized water

Measurements at 37 °C

NOMINAL VALUE: pH ~ 4.0

 

xi   measured mass fraction reported by laboratory iLabi

ui   combined standard uncertainty of xi

  Labi xi ui
  dimensionless dimensionless
  BFKH 4.1156 0.0027
  BIM 4.1182 0.0022
  CENAM 4.1577 0.0171
  CMI 4.1158 0.0009
  INMETRO 4.1176 0.0015
  NIM 4.1132 0.0018
  NMIJ 4.1155 0.0013
  VNIIFTRI 4.1158 0.0018