Comparison
Comparison close
Results

CCQM-K156

MEASURAND         L-PFOA in ground water

NOMINAL VALUE       5 ng/kg

 

Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui at a 95 % level of confidence, both expressed in ng/kg.

mass fraction
Di  (ng/kg)
Participating institutes

Results given in absolute values.

 

 

 

CCQM-K156

MEASURAND         L-PFOA in ground water

NOMINAL VALUE       5 ng/kg

 

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

relative mass fraction
Di  / %
Participating institutes

Results given in relative values.

CCQM-K156

MEASURAND         L-PFOS in ground water

NOMINAL VALUE       4 ng/kg

 

Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui at a 95 % level of confidence, both expressed in ng/kg.

mass fraction
Di  (ng/kg)
Participating institutes

Results given in absolute values.

 

 

CCQM-K156

MEASURAND         L-PFOS in ground water

NOMINAL VALUE       4 ng/kg

 

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

relative mass fraction
Di  / %
Participating institutes

Results given in relative values.

Comparison
Comparison close
Results

CCQM-K156

MEASURAND         L-PFOA in ground water

NOMINAL VALUE       5 ng/kg

 

Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui at a 95 % level of confidence, both expressed in ng/kg.

LABi Di Uneg,i Upos,i
ng/kg
ng/kg
ng/kg
BAM -2.2 1.1
NMIA -0.28 0.91
GL -0.22 1.7
UME -0.21 0.95
SYKE -0.12 1.2
NIM 0.48 1.6
VNIIM 0.57 0.93
Participating institutes
CCQM-K156

Results given in absolute values.

 

 

 

CCQM-K156

MEASURAND         L-PFOA in ground water

NOMINAL VALUE       5 ng/kg

 

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

LABi Di Uneg,i Upos,i
%
%
%
BAM -45 22
NMIA -5.7 19
GL -4.5 35
UME -4.3 19
SYKE -2.5 25
NIM 10 33
VNIIM 12 19
Participating institutes
CCQM-K156

Results given in relative values.

CCQM-K156

MEASURAND         L-PFOS in ground water

NOMINAL VALUE       4 ng/kg

 

Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui at a 95 % level of confidence, both expressed in ng/kg.

LABi Di Uneg,i Upos,i
ng/kg
ng/kg
ng/kg
VNIIM -1.8 0.78
BAM -0.43 0.84
UME -0.11 0.89
GL 0.12 1.3
NMIA 0.15 0.81
NIM 0.17 1.4
SYKE 0.66 1.1
Participating institutes
CCQM-K156

Results given in absolute values.

 

 

CCQM-K156

MEASURAND         L-PFOS in ground water

NOMINAL VALUE       4 ng/kg

 

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

LABi Di Uneg,i Upos,i
%
%
%
VNIIM -47 21
BAM -11 22
UME -2.9 23
GL 3.2 34
NMIA 4.0 21
NIM 4.5 37
SYKE 17 29
Participating institutes
CCQM-K156

Results given in relative values.

Comparison
Comparison close
CC comparison
Linked comparison
CCQM-K156
Metrology area, Sub-field Chemistry and Biology, Organics
Description Perfluorinated contaminants in water
Time of measurements 2018 - 2019
Status Approved for equivalence
Final Reports of the comparisons
Measurand Mass fraction of L-PFOA and L-PFOS in ng/kg
Transfer device Samples
Comparison type Key Comparison
Consultative Committee CCQM (Consultative Committee for Amount of Substance)
Conducted by CCQM (Consultative Committee for Amount of Substance)
Pilot institute UME
TÜBITAK Ulusal Metroloji Enstitüsü
Türkiye
Contact person Mine Bilsel

First Name Last Name
wwww@ww.www +356719836 Institute 1 Institute 1 Khmelnitskiy
Pilot laboratory
UME

TÜBITAK Ulusal Metroloji Enstitüsü, Türkiye, EURAMET

BAM

Bundesanstalt für Materialforschung und -prüfung, Germany, EURAMET

GL

Government Laboratory, Hong Kong, China, APMP

MIKES-SYKE

Finnish Environment Institute, Finland, EURAMET

NIM

National Institute of Metrology, China, APMP

NMIA

National Measurement Institute, Australia, Australia, APMP

VNIIM

D.I. Mendeleyev Institute for Metrology, Rosstandart, Russian Federation, COOMET

Comparison
Comparison close
Results

CCQM-K156

MEASURAND         L-PFOA in ground water

NOMINAL VALUE       5 ng/kg

 

The key comparison reference value xR and its associated standard uncertainty uR are computed using a hierarchical Bayesian random effects model of the reported results.

 

        xR = 4.9 ng/kg     uR = 0.4 ng/kg

 

The degree of equivalence of laboratory i relative to the key comparison reference value xR is given by a pair of terms, both expressed in ng/kg, where

Di = (xi - xR) and its expanded uncertainty Ui at a 95 % level of confidence where Uik ui , k representing the coverage factor to obtain 95 % level of confidence.

The degree of equivalence is also given in relative terms by Di = (xI - xR) /xand its relative expanded uncertainty Ui at a 95 % level of confidence, both expressed in %.

CCQM-K156

MEASURAND         L-PFOS in ground water

NOMINAL VALUE       4 ng/kg

 

The key comparison reference value xR and its associated standard uncertainty uR are computed using a hierarchical Bayesian random effects model of the reported results.

 

        xR = 3.8 ng/kg     uR = 0.4 ng/kg

 

The degree of equivalence of laboratory i relative to the key comparison reference value xR is given by a pair of terms, both expressed in ng/kg, where

Di = (xi - xR) and its expanded uncertainty Ui at a 95 % level of confidence where Uik ui , k representing the coverage factor to obtain 95 % level of confidence.

The degree of equivalence is also given in relative terms by Di = (xI - xR) /xand its relative expanded uncertainty Ui at a 95 % level of confidence, both expressed in %.

Comparison
Comparison close
Results

CCQM-K156

MEASURAND         L-PFOA in ground water

NOMINAL VALUE       5 ng/kg

 

xi   measured mass fraction reported by laboratory iLabi

ui  combined standard uncertainty of xi

ki        coverage factor reported by laboratory i

Ui   expanded uncertainty of xi at 95 % level of confidence where Ui = kiui

               
  Labi xi u (xi) u (xi) ki U (xi) U (xi)
  ng/kg ng/kg % ng/kg %
  BAM 2.749 0.359 13 2 0.717 26
  NMIA 4.65 0.08 1.8 2.36 0.19 4
  GL 4.71 0.72 15 2 1.43 30
  UME 4.72 0.19 4.0 2 0.38 8
  SYKE 4.81 0.41 8.5 2 0.82 17
  NIM 5.41 0.72 13 2 1.44 27
  VNIIM 5.50 0.17 3.2 2 0.35 6
               

 

CCQM-K156

MEASURAND         L-PFOS in ground water

NOMINAL VALUE       4 ng/kg

 

xi   measured mass fraction reported by laboratory iLabi

ui  combined standard uncertainty of xi

ki        coverage factor reported by laboratory i

Ui   expanded uncertainty of xi at 95 % level of confidence where Ui = kiui

 

               
  Labi xi u (xi) u (xi) ki U (xi) U (xi)
  ng/kg ng/kg % ng/kg %
  VNIIM 2.04 0.07 3.4 2 0.14 7
  BAM 3.36 0.12 3.6 2 0.24 7
  UME 3.68 0.20 5.0 2 0.39 11
  GL 3.91 0.50 14.0 2 1.0 26
  NMIA 3.94 0.08 1.9 2.31 0.17 4
  NIM 3.96 0.58 15 2 1.2 29
  SYKE 4.45 0.38 8.5 2 0.76 17