Comparison Display

CIPM MRA PARTICIPANTS

The KCDB - the BIPM key comparison database – supports the CIPM MRA. The KCDB contains information on the internationally recognized Calibration and Measurement Capabilities (CMCs) for services available from the participating institutes, and the key and supplementary comparisons supporting these CMCs.

All data listed in the KCDB have been reviewed and approved within the CIPM Mutual Recognition Arrangement

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CIPM MRA PARTICIPANTS

CMC statistics

CMC statistics

Comparison statistics

CCQM-K161

MEASURAND Mass fraction of chloride in seawater

NOMINAL VALUE 16 mg/g to 25 mg/g

Degrees of equivalence represented by D_i = (x_I - x_R) and its expanded uncertainty U_i at a 95 % level of confidence, both expressed in mg/g.

Mass fraction of chloride

D_i / mg/g

Participating institutes

*U_i for participants (marked with *) was estimated after summing in quadrature the participant's reported uncertainty value and the dark uncertainty (tau) associated with the key comparison reference value (KCRV) because estimation using the reported uncertainty value alone results in non equivalence with the KCRV.

CCQM-K161

MEASURAND Mass fraction of sulfate in seawater

NOMINAL VALUE 1 mg/g to 4 mg/g

Degrees of equivalence represented by D_i = (x_I - x_R) and its expanded uncertainty U_i at a 95 % level of confidence, both expressed in mg/g.

Mass fraction of sulfate

D_i / mg/g

Participating institutes

*U_i for participants (marked with *) was estimated after summing in quadrature the participant's reported uncertainty value and the dark uncertainty (tau) associated with the key comparison reference value (KCRV) because estimation using the reported uncertainty value alone results in non equivalence with the KCRV.

CCQM-K161

MEASURAND Mass fraction of bromide in seawater

NOMINAL VALUE 30 mg/kg to 100 mg/kg

Degrees of equivalence represented by D_i = (x_I - x_R) and its expanded uncertainty U_i at a 95 % level of confidence, both expressed in mg/kg.

Mass fraction of bromide

D_i / mg/kg

Participating institutes

*U_i for participants (marked with *) was estimated after summing in quadrature the participant's reported uncertainty value and the dark uncertainty (tau) associated with the key comparison reference value (KCRV) because estimation using the reported uncertainty value alone results in non equivalence with the KCRV.

CCQM-K161

MEASURAND Mass fraction of nitrate in seawater

NOMINAL VALUE 1 mg/kg to 5 mg/kg

Degrees of equivalence represented by D_i = (x_I - x_R) and its expanded uncertainty U_i at a 95 % level of confidence, both expressed in mg/kg.

Mass fraction of nitrate

D_i / mg/kg

Participating institutes

*U_i for participants (marked with *) was estimated after summing in quadrature the participant's reported uncertainty value and the dark uncertainty (tau) associated with the key comparison reference value (KCRV) because estimation using the reported uncertainty value alone results in non equivalence with the KCRV.

CCQM-K161

MEASURAND Mass fraction of phosphate (as P) in seawater

NOMINAL VALUE 20 µg/kg to 100 µg/kg

Degrees of equivalence represented by D_i = (x_I - x_R) and its expanded uncertainty U_i at a 95 % level of confidence, both expressed in µg/kg.

Mass fraction of phosphate as phosphorus

D_i / µg/kg

Participating institutes

*U_i for participants (marked with *) was estimated after summing in quadrature the participant's reported uncertainty value and the dark uncertainty (tau) associated with the key comparison reference value (KCRV) because estimation using the reported uncertainty value alone results in non equivalence with the KCRV.

CCQM-K161

MEASURAND Mass fraction of chloride in seawater

NOMINAL VALUE 16 mg/g to 25 mg/g

Degrees of equivalence represented by D_i = (x_I - x_R) and its expanded uncertainty U_i at a 95 % level of confidence, both expressed in mg/g.

	LAB_i	D_i	U_neg,i	U_pos,i
		mg/g	mg/g	mg/g
	INM (CO)	-0.623	0.678
	VNIIFTRI*	-0.457	0.556
	NIS	-0.124	0.572
	NIM	-0.018	0.154
	NIMT	0.009	0.141
	HSA	0.027	0.531
	UME	0.147	0.201
	VNIIM	0.161	0.863
	GL	0.177	0.442
	NMIJ	0.447	0.520

Participating institutes

CCQM-K161

*U_i for participants (marked with *) was estimated after summing in quadrature the participant's reported uncertainty value and the dark uncertainty (tau) associated with the key comparison reference value (KCRV) because estimation using the reported uncertainty value alone results in non equivalence with the KCRV.

CCQM-K161

MEASURAND Mass fraction of sulfate in seawater

NOMINAL VALUE 1 mg/g to 4 mg/g

Degrees of equivalence represented by D_i = (x_I - x_R) and its expanded uncertainty U_i at a 95 % level of confidence, both expressed in mg/g.

	LAB_i	D_i	U_neg,i	U_pos,i
		mg/g	mg/g	mg/g
	PTB*	-0.131	0.264
	UME*	-0.121	0.265
	NIS	-0.032	0.090
	NIMT	-0.010	0.053
	GL	-0.004	0.073
	NIM	0.007	0.054
	HSA	0.010	0.090
	VNIIM	0.064	0.376
	NMIJ*	0.140	0.284
	VNIIFTRI*	0.263	0.263

Participating institutes

CCQM-K161

*U_i for participants (marked with *) was estimated after summing in quadrature the participant's reported uncertainty value and the dark uncertainty (tau) associated with the key comparison reference value (KCRV) because estimation using the reported uncertainty value alone results in non equivalence with the KCRV.

CCQM-K161

MEASURAND Mass fraction of bromide in seawater

NOMINAL VALUE 30 mg/kg to 100 mg/kg

Degrees of equivalence represented by D_i = (x_I - x_R) and its expanded uncertainty U_i at a 95 % level of confidence, both expressed in mg/kg.

	LAB_i	D_i	U_neg,i	U_pos,i
		mg/kg	mg/kg	mg/kg
	NIMT*	-47.91	20.8
	VNIIM*	-18.34	23.7
	NIS*	-11.53	21.0
	VNIIFTRI	-1.584	4.95
	NIM	1.516	4.95
	UME	2.106	4.98
	NMIJ	3.616	5.13
	PTB*	8.726	20.6

Participating institutes

CCQM-K161

*U_i for participants (marked with *) was estimated after summing in quadrature the participant's reported uncertainty value and the dark uncertainty (tau) associated with the key comparison reference value (KCRV) because estimation using the reported uncertainty value alone results in non equivalence with the KCRV.

CCQM-K161

MEASURAND Mass fraction of nitrate in seawater

NOMINAL VALUE 1 mg/kg to 5 mg/kg

Degrees of equivalence represented by D_i = (x_I - x_R) and its expanded uncertainty U_i at a 95 % level of confidence, both expressed in mg/kg.

	LAB_i	D_i	U_neg,i	U_pos,i
		mg/kg	mg/kg	mg/kg
	NIMT*	-1.165	0.336
	NIS	-0.091	0.304
	UME	-0.081	0.094
	NMIJ	-0.013	0.077
	NIM	-0.004	0.074
	NRC	-0.002	0.074
	GL	0.009	0.136
	VNIIFTRI*	0.463	0.332

Participating institutes

CCQM-K161

*U_i for participants (marked with *) was estimated after summing in quadrature the participant's reported uncertainty value and the dark uncertainty (tau) associated with the key comparison reference value (KCRV) because estimation using the reported uncertainty value alone results in non equivalence with the KCRV.

CCQM-K161

MEASURAND Mass fraction of phosphate (as P) in seawater

NOMINAL VALUE 20 µg/kg to 100 µg/kg

Degrees of equivalence represented by D_i = (x_I - x_R) and its expanded uncertainty U_i at a 95 % level of confidence, both expressed in µg/kg.

	LAB_i	D_i	U_neg,i	U_pos,i
		µg/kg	µg/kg	µg/kg
	VNIIFTRI*	-26.00	23.18
	NRC	0.938	5.638
	NMIJ	0.948	5.661
	NIM	0.988	5.684
	UME	3.148	5.720

Participating institutes

CCQM-K161

*U_i for participants (marked with *) was estimated after summing in quadrature the participant's reported uncertainty value and the dark uncertainty (tau) associated with the key comparison reference value (KCRV) because estimation using the reported uncertainty value alone results in non equivalence with the KCRV.

Comparison

Comparison close

CCQM-K161

Information & contact
Participants

Metrology area, Sub-field	Chemistry and Biology, Inorganics
Description	Anions in seawater
Time of measurements	2021 - 2022
Status	Approved for equivalence

Final Reports of the comparisons	CCQM-K161 Final report 2024 23pp
References	CCQM-K161 Technical protocol
Measurand	Mass fraction of chloride, sulfate, bromide, nitrate and phosphate (as P) in sea water Mass fraction ranges: Chloride : from 16 mg/g to 25 mg/g; Sulfate : from 1 mg/g to 4 mg/g; Bromide : from 30 mg/kg to 100 mg/kg; Nitrate : from 1 mg/kg to 5 mg/kg; Phosphate (as P) : from 20 µg/kg to 100 µg/kg
Transfer device	The sample is a mixture of seawater sampling from East China Sea and North Pacific with the PO₄^3-spiking.

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 06 August 2024
Pilot institute	NIM National Institute of Metrology China
Contact person	Jingbo Chao +86 10 64225471

Pilot laboratory
NIM	National Institute of Metrology, China, APMP

GL	Government Laboratory, Hong Kong, China, APMP

HSA	Health Science Authority, Singapore, APMP

INM (CO)

Instituto Nacional de Metrología de Colombia, Colombia, SIM

NIMT	National Institute of Metrology (Thailand), Thailand, APMP

NIS	National Institute for Standards, Egypt, AFRIMETS

NIST	National Institute of Standards and Technology, United States, SIM

NMIJ AIST

National Metrology Institute of Japan, Japan, APMP

NRC	National Research Council, Canada, SIM

PTB	Physikalisch-Technische Bundesanstalt, Germany, EURAMET

UME	TÜBITAK Ulusal Metroloji Enstitüsü, Türkiye, EURAMET

VNIIFTRI

Institute of Physical Technical and Radiotechnical Measurements, Rosstandart, Russian Federation, COOMET

VNIIM

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

CCQM-K161

MEASURAND Mass fraction of chloride in seawater

NOMINAL VALUE 16 mg/g to 25 mg/g

The key comparison reference value x_R and its associated standard uncertainty u_R were calculated using the Hierarchical Laplace-Gauss statistical model following the NIST Decision Tree, as explained on pages 18 and 19 of the CCQM-K161 Final report.

x_R = 19.04 mg/g u_R = 0.06761 mg/g

The degree of equivalence of laboratory i relative to the key comparison reference value x_R is given by a pair of terms, both expressed in mg/g:

D_i = (x_i - x_R) and its expanded uncertainty U_i at a 95 % level of confidence is calculated as explained on page 24 of the CCQM-K161 Final report.

CCQM-K161

MEASURAND Mass fraction of sulfate in seawater

NOMINAL VALUE 1 mg/g to 4 mg/g

The key comparison reference value x_R and its associated standard uncertainty u_R were calculated using the Hierarchical Laplace-Gauss statistical model following the NIST Decision Tree, as explained on pages 18 and 19 of the CCQM-K161 Final report.

x_R = 2.63 mg/g u_R = 0.02578 mg/g

The degree of equivalence of laboratory i relative to the key comparison reference value x_R is given by a pair of terms, both expressed in mg/g:

D_i = (x_i - x_R) and its expanded uncertainty U_i at a 95 % level of confidence is calculated as explained on page 24 of the CCQM-K161 Final report.

CCQM-K161

MEASURAND Mass fraction of bromide in seawater

NOMINAL VALUE 30 mg/kg to 100 mg/kg

The key comparison reference value x_R and its associated standard uncertainty u_R were calculated using the Hierarchical Laplace-Gauss statistical model following the NIST Decision Tree, as explained on pages 18 and 19 of the CCQM-K161 Final report. NIMT result for bromide was excluded from the calculation of the KCRV (see page 18 of the CCQM-K161 Final report).

x_R = 64.25 mg/kg u_R = 2.497 mg/kg

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

D_i = (x_i - x_R) and its expanded uncertainty U_i at a 95 % level of confidence is calculated as explained on page 24 of the CCQM-K161 Final report.

CCQM-K161

MEASURAND Mass fraction of nitrate in seawater

NOMINAL VALUE 1 mg/kg to 5 mg/kg

The key comparison reference value x_R and its associated standard uncertainty u_R were calculated using the Hierarchical Laplace-Gauss statistical model following the NIST Decision Tree, as explained on pages 18 and 19 of the CCQM-K161 Final report. NIMT result for nitrate was excluded from the calculation of the KCRV (see page 18 of the CCQM-K161 Final report).

x_R = 1.511 mg/kg u_R = 0.03507 mg/kg

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

D_i = (x_i - x_R) and its expanded uncertainty U_i at a 95 % level of confidence is calculated as explained on page 24 of the CCQM-K161 Final report.

CCQM-K161

MEASURAND Mass fraction of phosphate (as P) in seawater

NOMINAL VALUE 20 µg/kg to 100 µg/kg

The key comparison reference value x_R and its associated standard uncertainty u_R were calculated using the Hierarchical Laplace-Gauss statistical model following the NIST Decision Tree, as explained on pages 18 and 19 of the CCQM-K161 Final report.

x_R = 59.18 µg/kg u_R = 2.723 µg/kg

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

D_i = (x_i - x_R) and its expanded uncertainty U_i at a 95 % level of confidence is calculated as explained on page 24 of the CCQM-K161 Final report.

CCQM-K161

MEASURAND Mass fraction of chloride in seawater

NOMINAL VALUE 16 mg/g to 25 mg/g

x_i measured mass fraction reported by laboratory i, Lab_i

u_i combined standard uncertainty of x_i

Reported results of chloride

	Lab_i	x_i	u_i
	Lab_i	mg/g	mg/g
	INM (CO)	18.42	0.339
	VNIIFTRI	18.5857	0.007094
	NIS	18.919	0.280
	NIM	19.025	0.036
	NIMT	19.052	0.01252
	HSA	19.07	0.26
	UME	19.19	0.074
	VNIIM	19.204	0.4326
	GL	19.22	0.21
	NMIJ	19.49	0.25

CCQM-K161

MEASURAND Mass fraction of sulfate in seawater

NOMINAL VALUE 1 mg/g to 4 mg/g

x_i measured mass fraction reported by laboratory i, Lab_i

u_i combined standard uncertainty of x_i

Reported results of sulfate

	Lab_i	x_i	u_i
	Lab_i	mg/g	mg/g
	PTB	2.4987	0.025
	UME	2.509	0.022
	NIS	2.598	0.038
	NIMT	2.620	0.00234
	GL	2.626	0.026
	NIM	2.637	0.006
	HSA	2.640	0.031
	VNIIM	2.6938	0.1887
	NMIJ	2.77	0.06
	VNIIFTRI	2.8931	0.007108

CCQM-K161

MEASURAND Mass fraction of bromide in seawater

NOMINAL VALUE 30 mg/kg to 100 mg/kg

x_i measured mass fraction reported by laboratory i, Lab_i

u_i combined standard uncertainty of x_i

Reported results of bromide

	Lab_i	x_i	u_i
	Lab_i	mg/kg	mg/kg
	NIMT	16.345 (47.21)	0.10455
	VNIIM	45.91	6.005
	NIS	52.72	2.03
	VNIIFTRI	62.6697	0.01086
	NIM	65.77	0.207
	UME	66.36	0.25
	NMIJ	67.87	0.66
	PTB	72.98	0.53

Values in brackets () represent recalculated results by the participant (see page 13 of the CCQM-K161 Final report)

CCQM-K161

MEASURAND Mass fraction of nitrate in seawater

NOMINAL VALUE 1 mg/kg to 5 mg/kg

x_i measured mass fraction reported by laboratory i, Lab_i

u_i combined standard uncertainty of x_i

Reported results of nitrate

	Lab_i	x_i	u_i
	Lab_i	mg/kg	mg/kg
	NIMT	0.346 (1.432)	0.007661 (0.03085)
	NIS	1.42	0.15
	UME	1.430	0.031
	NMIJ	1.498	0.014
	NIM	1.507	0.009
	NRC	1.5087	0.0073
	GL	1.520	0.059
	VNIIFTRI	1.9740	0.01062
	NIM*	1.509	0.013

Values in brackets () represent recalculated results by the participant (see page 13 of the CCQM-K161 Final report)

*Information values.

CCQM-K161

MEASURAND Mass fraction of phosphate (as P) in seawater

NOMINAL VALUE 20 µg/kg to 100 µg/kg

x_i measured mass fraction reported by laboratory i, Lab_i

u_i combined standard uncertainty of x_i

Reported results of phosphate

	Lab_i	x_i	u_i
	Lab_i	µg/kg	µg/kg
	VNIIFTRI	33.1810	0.7542
	NRC	60.12	0.20
	NMIJ	60.13	0.31
	NIM	60.17	0.358
	UME	62.33	0.59