CCQM-K106: Pb, As and Hg measurements in cosmetic (cream ... · PDF fileCCQM-K106 Final report CCQM-K106: Pb, As and Hg measurements in cosmetic (cream) Final report Authors and colleagues

CCQM-K106 Final report

CCQM-K106: Pb, As and Hg measurements in cosmetic (cream)

Final report

Authors and colleagues contributed to the measurements and/or reports:

Jun Wang1, Qian Wang1, Randa Nasr Ahmed Yamani2, Adel B. Shehata2,

Radojko Jacimovic3, Majda Pavlin3, Milena Horvat3, Y.P.Tsoi4, C K TSANG4,

Richard Shin5, Benjamat Chailap6, Charun Yafa6, Rodrigo Caciano de Sena7,

Marcelo de Almeida7, Yong-Hyeon Yim8, Kyoung-Seok Lee8, Sook Heun Kim8,

Leonid Konopelko9, Betül ARI10, Nilgün TOKMAN10, Olaf Rienitz11,

Reinhard Jaehrling11, Carola Pape11

1 NIM 2NIS 3JSI 4GLHK 5HSA 6NIMT 7INMETRO 8KRISS 9VNIIM 10 TÜBITAK UME 11PTB

National Institute of Metrology P. R. China October, 2014

CCQM-K106 Final report

CONTENTS

1. INTRODUCTION ............................................................................................................. 1

2. LIST OF PARTICIPANTS ............................................................................................... 2

3. TIME SCHEDULE ............................................................................................................ 3

4. SAMPLE ............................................................................................................................. 3

5. INSTRUCTIONS TO PARTICIPANTS ......................................................................... 5

6. METHODS OF MEASUREMENT ................................................................................. 5

7. RESULTS AND DISCUSSION ...................................................................................... 10

7.1 General ......................................................................................................................... 10

7.2 Screening the data for consistency and anomalous values .......................................... 13

7.3 Calculation of the reference mass fraction values and associated uncertainties ......... 13

7.4 KCRV and KCRU ...................................................................................................... 14

7.5 Equivalence statements ................................................................................................ 16

8. DISCUSSION ................................................................................................................... 20

9. CONCLUSION ................................................................................................................ 21

10. ACKNOWLEDGEMENTS ............................................................................................ 21

11. REFERENCES ............................................................................................................... 21

APPENDIX A: DEMONSTRATED INORGANIC CORE CAPABILITIES .................. 22

APPENDIX B: INVITATION, TECHNICAL PROTOCOL AND REPORTING FORMS ...........................................................................................................................................34

CCQM-K106 Final report Page 1/44

1. INTRODUCTION Cosmetics are used in practically all walks of life as a means of improving skin and beautifying complexion. In recent years, more and more attention has been paid to the cosmetic safety. In response to cosmetic safety issue, the accurate measurement of the heavy metals in cosmetic is, therefore, particularly important. NMIs from different countries should establish their chemical metrology traceability system in this area, which include both measurement methods research and certain CRMs development. It should be noted that because the matrix of many cosmetics are complex and the contents of the heavy metals are relatively low, it still is a challenging task to measure the analytes with high accuracy and precision. CCQM-K106 & P128.1 followed up CCQM pilot study “CCQM-P128: Pb, As measurements in cosmetic (cream)” coordinated by the National Institute of Metrology, China (NIM) in 2009. The cream was selected as the testing material, which is widely used as a daily skin care worldwide. This is the first CCQM key comparison regarding the measurement of toxic metal elements with the cosmetic matrix, which includes pure water, liquid paraffin, silicone oil, synthetic squalane, hyaluronic acid, glycerin, propylene glycol, allantoin, preservative and so on. The aim of CCQM-K106 is to demonstrate the capability of participating NMIs and designated institutes in measuring the contents of poisonous elements, including lead, arsenic and mercury in a cosmetic sample (cream), and support CMC claims relating to inorganic elements in cosmetic materials and similar chemical industry products.


2. LIST OF PARTICIPANTS

12 institutes registered in CCQM-K106. The list of all the participating institutes is shown in Table 1 according to a sequence of the time of registration.

Table 1. List of participants Lab No. Institute Full Name Country Contact Person Pb As Hg

01 NIS National Institute for Standards Egypt

Randa Nasr Ahmed Yamani, Prof. Dr. Adel B. Shehata

√ √ √

02 BIM Bulgarian Institute of Metrology Bulgaria Dr. Boriana Kotzeva √ √

03 JSI Jozef Stefan Institute Slovenia Prof. Dr. Milena

Horvat

√ √

04

GLHK Government Laboratory of Hong Kong Special Administrative Region

China Mr C K TSANG √ √ √

05 HSA Health Sciences Authority Singapore Dr. Richard Shin √ √ √

06 NIMT National Institute of Metrology Thailand Benjamat Chailap

and Charun Yafa √ √ √

07

INMETRO Instituto Nacional de Metrologia, Qualidade e Tecnologia

Brasil Rodrigo Caciano de Sena/ Marcelo de

Almeida √ √ √

08 KRISS Korea Research Institute of Standards and Science

Republic of Korea Yong-Hyeon Yim √ √ √

09 VNIIM D.I. Mendeleyev Institute for Metrology

Russia Prof. Leonid Konopelko √ √ √

10 TÜBİTAK UME TÜBİTAK Ulusal Metroloji Enstitüsü

Turkey Nilgün TOKMAN √ √ √

11 PTB Physikalisch-Technische Bundesanstalt

Germany Dr.Olaf Rienitz √ √

12 NIM National Institute of Metrology, China

China Wang Qian √ √ √

Remark: BIM did not submit the results. GLHK and INMETRO did not submit the result of Hg. Two NMIs and one designed institute registered CCQM P128.1. However, CENA/USP did not received samples due to the local customs, NIS and NIM did not submit any different information between CCQM-K106 and P128.1 in terms of measurement method and result. In this case, this pilot study is not necessary, and IAWG chairman Dr. Sargent suggested removing CCQM P128.1 at the IAWG meeting held in Paris on 7-8 April 2014.


3. TIME SCHEDULE Call for Participation: April 2013 Deadline for registration: May 31, 2013 Dispatch of the samples: June 2013 Deadline for receipt of the result report: December 15, 2013 Discussing of the result: CCQM/ IAWG 1nd meeting of 2014 4. SAMPLE Sample Preparation The cream matrix sample was prepared under the guidance of professional technicians. The formula of the cream was carefully chosen to quite match with a real cosmetic. During the cream material preparation, the appropriate amount of chemical compounds of Pb(NO3)2 , Na3AsO4 and HgCl2 solution were added into the aqueous phase respectively. And then the mixture was emulsified and homogenized with violently stirring. After pre-homogeneity investigated, the cream sample was packaged into clean brown glass bottles covered with a PE/butyl rubber stopper sealed with aluminium crimp tops. Each unit was vacuum packed in aluminium-nylon pouch. The approximate levels of concentrations are: Pb (5~10) mg/kg; As (1~10) mg/kg; Hg (0.1~2) mg/kg. Homogeneity test 15 bottles were chosen randomly from 200 bottles to test b-bottle homogeneity, and two samples were tested independently from one bottle for in-bottle homogeneity. For Pb and As, 0.1g sample were measured by ICP-MS after microwave digestion of sample. Direct Mercury Analyzer (DMA-80) was adopted to determine Hg and the sampling weight was 0.03~0.06g. ANOVA technique was applied to assess the between bottle heterogeneity and the standard uncertainty originated from the between bottle heterogeneity was calculated using the formula given below in accordance with ISO Guide 35:2006 [1]. The results are summarized in Table 2.

MSwithin

withinbb n

MSuν

2⋅= (1)

Where: ubb standard uncertainty due to between bottles heterogeneity MSwithin mean square of within bottles variance νMSwithin degree of freedom of MSwithin n number of subsample

Table 2. Summary of homogeneity study results

Measurand ANOVA test on heterogeneity Relative standard uncertainty due to

between bottle heterogeneity, ubb (%) F-statistics Critical value

Pb 1.56 2.42 0.43

As 0.44 2.42 0.55

Hg 1.89 2.42 0.42

The results indicated that no significant heterogeneity was observed in the testing material and hence its quality was fit for the purpose of this comparison programme.

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5. INSTRUCTIONS TO PARTICIPANTS

The instruction relating to CCQM-K106 & P128.1 was sent to each participant by e-mail, which consisted of technical protocol, results report form and inorganic core capabilities tables.

The participants were free to use any appropriate method(s) of their choice. To avoid any decomposition and losing of water content, the samples should be kept sealed until they were used. They should be stored at room temperature (18～25℃) in its original bottle, capped tightly and not exposed to intense direct light and ultraviolet radiation. Sample should be carefully opened for analysis in a short period of time to avoid contamination. An injector was recommended to use for sampling.

A Results Report was sent to the participants by email while the samples were dispatched. At least 6 independent determinations were requested to perform for each element. The results were reported as mass faction (mg/kg). Calculation of the uncertainty expressed as a combined standard uncertainty and an expanded uncertainty at 95% confidence. In order to allow a sufficient evaluation of the comparison, the report was required to include a detail description of the applied method of measurement, information about sample digestion and preparation, information about the reference material used for calibration.

All participants were requested to fill and submit the inorganic core capability tables to the coordinator. The relevant information were compiled and summarized in the Annex A.

6. METHODS OF MEASUREMENT

The methods of measurement were free to be selected by the participants. For this comparison, microwave assisted digestion, ICP-MS and IDMS analytical techniques were adopted by the majority of participants. According to the Results Report submitted by each participant, the summary of measurement methods and detailed information are shown in Table 3 and Table 4 respectively.

Table 3. Summary of the measurement methods

Institute Digest Solution Digest Method Analysis method Sample mass(g)

NIS HNO3+HClO4+H2O2 Microwave digestion AAS(Pb, As, Hg) 0.5

JSI / Non-destructive technique(As)

Combustion(Hg) AAS(DMA) (Hg), INAA(As)

0.029-0.060(Hg),

0.24-0.27(As)

GLHK HNO3+H2O2+HF Microwave digestion

ICP-MS(Pb, As, Gravimetric Standard Addition & Internal

Standard) 0.3

HSA HNO3+H2O2+HF Microwave digestion

IDMS(Pb,Hg), ICP-MS(As, Gravimetric Standard Addition &

Internal Standard) 0.3

NIMT HNO3+HF Microwave digestion

ID-ICP-MS(Pb,Hg), ICP-MS(As, Gravimetric Standard

Addition&Internal Standard) 0.2

INMETRO HNO3+H2O2+HF Microwave digestion ICP-MS(Pb,As) 0.35


KRISS HNO3+H2O2+HF Microwave digestion

ID-ICP-MS(Pb,Hg), ICP-MS(As, Standard Addition & Internal

Standard) 0.3

KRISS* / / INAA(As) 0.1

VNIIM HNO3+H2O2 Microwave digestion ICP-MS(Pb, As), AAS(Hg) 0.2

TÜBITAK UME HNO3+H2O2 +HF Microwave

digestion

Double IDMS(Pb), IDMS(Hg), ICP-MS(As, matrix matched external calibration method &

Internal Standard)

0.3

PTB HNO3+H2O Microwave digestion ID-ICP-MS (Pb, Hg) 0.3

NIM HNO3+H2O2+HF Microwave digestion

IDMS (Pb,Hg), ICP-MS(As, Standard Addition & Internal

Standard) 0.3

NIM* / / AAS(DMA)(Hg) 0.01-0.03


Table 4. Details of measurement methods

Institute Instrument Type of calibration Calibration standard(s) Use of CRM, Control sample

Procedure for Digestion

NIS AAS: (ZEEnit 700, Analytik jena, Germany)

External calibration(Pb, As,Hg)

Mercury, NIS CRM 1000 ± 12 mg/L, Lead, NIS CRM 1000 ± 10 mg/L, Arsenic, NIS CRM 1000 ± 10 mg/L

/ Temp. (ºC)

Pressure(bar)

Ramp (min)

Time (min)

Power (%)

75 14 5 1 82 100 21 3 3 82 150 28 7 4 82 180 35 5 12 82 50 0 1 30 0

The weighed sample was digested in 5 mL mixture (3:1) of concentrated nitric acid and perchloric acid for 2 hours on a hotplate at 150 ºC.（Pb, As）

JSI DMA: (direct mercury analyser, Milestone); 250 kW TRIGA Mark II reactor of the JSI, Ljubljana, Slovenia

External calibration Preparation of working standard solution from primary (stock) standard solution (9.954 ± 0.053 mg/g for k=2.18) or intermediate standard solution (5 μg/mL) Al-0.1%Au IRMM-530R alloy

NIST SRM-1547 Peach Leaves, DORM-4 (Fish protein certified reference material for trace metals) and DOLT-4 (Dogfish liver certified reference material for trace metals)

/

GLHK ICP-MS Gravimetric standard addition calibration (Pb, As, multi-element internal standard solution containing 72Ge and 165Ho were used as internal standards)

NIST SRM 3128 lead standard solution, NIST SRM 3103a arsenic standard solution

Pb, As in cosmetic cream, Source: GBW09305

Stage Max power(W)

Power(%)

Ramp(min)

Pressure(psi)

Temp (°C)

Hold (min)

1 1200 100 05:00 200 75 01:00 2 1200 100 03:00 300 100 03:00 3 1200 100 07:00 400 150 04:00 4 1200 100 05:00 500 180 12:00

HSA ICP-HR-MS(Thermo Scientific ELEMENT 2),

Exact matching IDMS(Pb, used 206Pb spike; Hg, used 201Hg spike), Standard addition calibration(As, used internal standard Ga)

201Hg and 206Pb isotope spikes from Oak Ridge National Laboratory, NIST SRM3133, NIST SRM3128 and BAM-Y004, NIST SRM 981, NIST SRM 3103a, NIST SRM 3119a.

Cosmetic cream from CCQM-P128.

Power/W 1000 Temperature/℃ 190 Ramp time/min 15 Hold time/min 25 Cool down time/min 30


NIMT ICP-MS: PerkinElmer SCIEX ELAN DRC II ICP-MS

ID-ICP-MS(Pb, used 206Pb spike; Hg, used 201Hg spike), Standard addition calibration(As, Rh (Rhodium) was used as an internal standard and carried on step of digestion)

NIST SRM 3103a, NIST SRM 3128, NIST SRM 3133

Pb and As in Cosmetic (Cream) from National Institute of Metrology (China), GBW09305 vial No.42. For Hg, matrix QC sample prepared from spiking appropriate concentration of Hg standard into sample blank.

The Multiwave 3000 microwave digestion machine was used for matrix decomposition with microwave power: ramp to 1200 W for 15 min and hold for 25 min and then cool down over 20 min. For Hg preservation, the vessels containing digests were immersed into an ice bath for 15 min. For As standard addition, Rh (Rhodium) was accurately weighed into microwave vessels as an internal standard and carried on step of digestion.

INMETRO ICP-MS: ELAN DRC II Perkin Elmer

External calibration(Pb, As)

Pb – SRM 3128 from NIST, As – SRM 3103a from NIST

As it was not available in the laboratory a similar CRM, we choose to perform recovery testing.

120 ºC (ramp 10 min) , 120ºC (hold -5 min), 180 ºC (ramp - 10 min) - 220 ºC (hold 15 min) The sample handling is not easy and aiming to avoid contamination and absorption of water, the sample was carefully transferred for a syringe. After this procedure, the subsamples were weighed directly in PFA tubes.

KRISS Magnetic sector ICP-MS (Element 2 from Thermo Scientific Inc., Germany)(Pb,As); Elan DRC ICP/MS (PerkinElmer, USA), ICP/MS hyphenated with cold vapor generation technique(Hg)

IDMS(Pb, used 206Pb spike), Standard addition calibration(As, used internal standard 73Ge),IDMS(Hg, used 200Hg spike)

KRISS Arsenic standard solution, KRISS Lead standard solution, KRISS Germanium standard solution, NIST SRM 981 and 982 KRISS mercury (Hg) standard solution

/ RT (at 0 min) - 200 (at 20 min) - 200 (at 40 min) - cooling

KRISS* High-purity germanium γ-ray detector, Spectroscopic amplifere (672, ORTEC, Oak Ridge, USA), Multichannel analyser (ASPEC-927, ORTEC, Oak Ridge, USA)

Direct comparator instrumental neutron activation analysis (INAA)

KRISS arsenic (As) standard solution

Cosmetic cream (CCQM-P128 sample)

/


VNIIM As，Pb: Agilent 8800 External calibration Pure standards for preparation of aqua standards are commercial standards which undergo in-house purity assessment by ICP-MS, AAS, OES, etc

CRM GBW(E) 090028 (NMI P.R. China)

StageMax Power

% Power

Ramp time

Pressure (psi)

Temp. 0С

Hold Time (min)

1 800 100 15:00 800 200 2 800 100 10:00 800 200 10:00

TÜBITAK UME

HR-ICPMS: Thermo Finnigan ELEMENT 2

Double IDMS(Pb ), IDMS(Hg), ICP-MS(As, matrix matched external calibration method & Internal Standard Y)

Pb: NIST SRM 3128, NIST SRM 982, NIST SRM 981, NIST 991 Hg: ERM 640, NIST SRM 3133 As: NIST SRM 3103a

HRM 2004a certified reference material is used for arsenic and lead measurements.

Mode Temperature Time, min

Ramp 150 0C 10

Hold 150 0C 15

Ramp 200 0C 7

Hold 200 0C 10

PTB HR-ICP-MS: Finnigan ElementXR, Thermo Fisher Scientific

ID-ICP-MS (Pb, used 207Pb spike; Hg, used 201Hg spike)

Pb: NIST SRM 981, Hg: in-house prepared reference, Alfa Aesar Spike materials: Pb-207, 153-c, Chemotrade, Hg-201, BAM, Germany

/ 2.5 mL 65 % HNO3 (subboiled, Merck p.a.) and 6.5 mL H2O was used to digest the samples in an MLS ETHOS-1600 microwave system within 1 h at 190 °C. After cooling down the solutions were evaporated to near dryness microwave-assisted within 3 h at 80 °C and 500 mbar.（Pb） 2.5 mL 65 % HNO3 (subboiled, Merck p.a.) and 4 mL H2O was used to digest the samples in an MLS Ultraclave microwave system within 2 h at 250 °C.（Hg）

NIM ICP-MS: Agilent 7500ce

IDMS(Pb, used 207Pb spike, Hg, used 202Hg spike), Standard addition calibration(As, used internal standard 74Ge)

NIM CRM As: GBW08611; Hg: GBW08617; Enriched Isotope 207Pb Spike Solution: GBW04442; Enriched Isotope 202Hg Spike Solution: GBW04443; NIST SRM 981

CRM GBW(E) 090028 Power Temperature Hold 1600W 200℃ 20min

NIM* Direct Mercury Analyzer: DMA-80, Milestone

External calibration NIM CRM: GBW08617 / /


7. RESULTS AND DISCUSSION

7.1 General

The measurement results of Pb, As and Hg in CCQM-K106 cream sample reported by each participant are summarised in Table 5~Table 7 respectively.

Table 5. Reported results of Pb

Institute Result (mg/kg) n u

(mg/kg) U

(mg/kg) k Analysis method

Sample No.- Original No.

NIS 7.73 6 0.40 0.80 2 AAS 3#-117,4#-108

GLHK 7.56 6 0.19 0.37 2 ICP-MS 9#-196,10#-74

HSA 7.46 8 0.09 0.19 2.0 IDMS 11#-127,12#-219

NIMT 7.62 9 0.10 0.19 2 IDMS 13#-107,14#-157

INMETRO 7.51 6 0.15 0.30 2 ICP-MS 15#-078

KRISS 7.479 6 0.034 0.075 2.2 IDMS 17#-200

VNIIM 7.1 6 0.255 0.5 2 ICP-MS 20#-104

TÜBITAK UME 7.55 14 0.10 0.19 2 IDMS 21#-205,22#-140

PTB 7.492 7 0.072 0.15 2.06 IDMS 23#-191,24#-199

NIM 7.468 7 0.107 0.213 2 IDMS 25#-139, 26#-232

Table 6. Reported results of As


(mg/kg) U



NIS 4.40 6 0.21 0.42 2 AAS 3#-117,4#-108

JSI 4.93 6 0.15 0.30 2 INAA 7#-125

GLHK 4.94 6 0.14 0.27 2 ICP-MS 9#-196,10#-74

HSA 4.94 8 0.11 0.21 2.0 ICP-MS 11#-127,12#-219

NIMT 4.89 9 0.11 0.21 2 ICP-MS 13#-107,14#-157

INMETRO 4.53 6 0.13 0.26 2 ICP-MS 15#-078

KRISS* 4.79 4 0.15 0.48 3.18 INAA 18#-223

KRISS 4.91 1 0.21 0.48 2.26 ICP-MS 18#-223


VNIIM 4.8 6 0.15 0.3 2 ICP-MS 20#-104

TÜBITAK UME 4.90 10 0.09 0.17 2 ICP-MS 21#-205,22#-140

NIM 4.989 6 0.107 0.215 2 ICP-MS 25#-139,26#-232

Note: KRISS submitted two results using different methods. Only the result obtained by ICP-MS was considered to calculate the KCRV.

Table 7. Reported results of Hg


(mg/kg) U



NIS 0.520 6 0.024 0.048 2 AAS 3#-117,4#-108

JSI 0.975 13 0.039 0.078 2 AAS(DMA) 7#-125

HSA 0.960 8 0.021 0.041 2.0 IDMS 11#-127,12#-219

NIMT 0.986 9 0.019 0.037 2 IDMS 13#-107,14#-157

KRISS 1.003 6 0.040 0.082 2.05 IDMS 17#-200,18#-223

VNIIM 1.01 6 0.035 0.07 2 AAS 20#-104

TÜBITAK UME 1.010 15 0.015 0.031 2 IDMS 21#-205,22#-140

PTB 0.9793 7 0.0065 0.013 2.00 IDMS 23#-191,24#-199

NIM 0.976 7 0.021 0.042 2 IDMS 25#-139,26#-232

NIM* 0.982 6 0.035 0.071 2 AAS(DMA) 27#-238,28#-183

Note: NIM submitted two results using different methods. Only the result obtained by IDMS was considered to calculate the KCRV. Fig.2~ Fig.4 shows the distribution for the results of CCQM-K106 for each measurand respectively. Error bar represents the standard uncertainty (u), as reported.

CCQM-K

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Table 8.

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Table 9. Results of calculation of consensus values and respective standard deviation (all data included) Measurand Pb As Hg

n 10 10 9

Arithmetic mean (mg/kg) 7.497 4.823 0.935

SD (mg/kg) 0.162 0.197 0.157

Median (mg/kg) 7.501 4.905 0.979

MADe (mg/kg) 0.067 0.052 0.029

Robust mean (mg/kg) 7.512 4.897 0.983

Robust SD (mg/kg) 0.074 0.063 0.026

Table 10. Results of calculation of consensus values and respective standard deviation (after removal of suspected extreme values)

Measurand Pb As Hg

n 8 8 8

Arithmetic mean (mg/kg) 7.517 4.912 0.987

SD (mg/kg) 0.055 0.055 0.019

Median (mg/kg) 7.501 4.920 0.983

MADe (mg/kg) 0.055 0.030 0.021

Robust mean (mg/kg) 7.513 4.923 0.983

Robust SD (mg/kg) 0.052 0.039 0.021

7.4 KCRV and KCRU

Based on the calculation results showed in Table 9, Table 10 and mentioned above discussion as well, the median and associated uncertainty are proposed as the KCRV and KCRU for CCQM-K106. The associated uncertainty is calculated using formulas (2) and (3) according to the CCQM Guidance Note [2]. The calculated KCRV and KCRU of the three measurands are listed in Table 11.

( )n

u MADe1.25KCRV ×= (2)

uU ×= 2 (3)

Table 11. Calculated KCRV and KCRU (after removal of suspected extreme values) Measurand Pb As Hg

n 8 8 8

KCRV (mg/kg) 7.501 4.920 0.983

u (mg/kg) 0.025 0.014 0.010

KCRU (k = 2) (mg/kg) 0.049 0.027 0.019

Urel (%) 0.7 0.6 1.9

The resustraight uncertainuncertain

ults for Pb, Aline representy (u (KCRnty.

As and Hg ints the KCR

RV)). The bar

Fig.5

Fig.6

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/44

g.7. The redsed standardand standard

d d d

7.5 Equ

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Where:

xi di U(

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ng to CCQMssed quantitanty of this deulated using

:

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d value xi fonties u(xi), tr each particivalence stat

Fig.7

statements

M Guidance Natively by tweviation (at aformulas (4)

value submimponent xi –ainty componsed at 95 % c

or measurandogether withipant in Tabl

tements for C

CCQM-K

CCQM-K10

Note [2], the dwo terms: itsa 95 % level ) and (5).

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CCQM-K106

K106 Final repo

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Page 16

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6/44

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Fig.8 Eqthe

Ta

In

N

G

H

N

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K

V

T

P

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nstitute

NIS

GLHK

HSA

NIMT

NMETRO

KRISS

VNIIM

TÜBITAK UM

TB

NIM te: * reported

tatement of L

CCQM-K

valence statexi

(mg/k

7.73

7.56

7.46

7.62

7.51

7.479

7.1*

ME 7.55

7.492

7.468d value is no

Lead for CCQ

K106 Final repo

ement of Lea

kg) u(x

(mg/k

* 0.4

6 0.1

6 0.0

2 0.1

1 0.1

9 0.03

* 0.25

5 0.1

2 0.07

8 0.10ot included in

QM-K106. P

ort

ad for CCQMi) kg)

d (mg/

0 0.22

9 0.0

9 -0.0

0 0.1

5 0.0

34 -0.0

55 -0.4

0 0.04

72 -0.0

07 -0.0n the calculat

Points show t

M-K106 di /kg)

U((mg

29 0.8

59 0.3

041 0.1

19 0.2

09 0.3

022 0.0

401 0.5

49 0.2

009 0.1

033 0.2tion of KCRV

the di, while

Page 17

(di) g/kg)

802

383

187

206

304

084

512

206

152

220 V.

the error bar

/44

rs denote

Fig.9 Eqthe

Ta

In

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V

T

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quivalence se U(di).

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nstitute

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SI

GLHK

HSA

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NMETRO

KRISS

KRISS

VNIIM

TÜBITAK UM

NIM Note: * repor

tatement of A

CCQM-K

ivalence statxi

(mg/k

4.40*

4.93

4.94

4.94

4.89

4.53*

4.79*

4.91

4.8

ME 4.90

4.989rted value is

Arsenic for C

K106 Final repo

tement of Ars

kg) u(x

(mg/k

* 0.2

3 0.1

4 0.14

4 0.1

9 0.1

* 0.1

* 0.1

1 0.2

0.1

0 0.0

9 0.10not included

CCQM-K10

ort

senic for CCi) kg)

d(mg/

1 -0.5

5 0.0

4 0.02

1 0.02

1 -0.0

3 -0.3

5 -0.1

1 -0.0

5 -0.1

9 -0.0

07 0.0d in the calcu

6. Points sho

CQM-K106 di /kg)

U((mg

520 0.4

10 0.3

20 0.2

20 0.2

030 0.2

390 0.2

30 0.3

010 0.4

20 0.3

020 0.1

69 0.2ulation of KC

ow the di, wh

Page 18

(di) g/kg)

421

301

281

222

222

262

301

421

301

182

216 CRV.

hile the error

/44

r bars denotee

Fig.10

Ta

In

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V

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P

N

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able 14. Equ

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SI

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KRISS

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TÜBITAK UM

TB

NIM

NIM Note: * repor

e statement oU(di).

CCQM-K

ivalence statxi

(mg/k

0.520

0.975

0.960

0.986

1.003

1.01

ME 1.010

0.979

0.976

0.982rted value is

of Mercury

K106 Final repo

tement of Me

kg) u(x

(mg/k

0* 0.02

5 0.03

0 0.02

6 0.01

3 0.04

1 0.03

0 0.01

93 0.00

6 0.02

2* 0.03 not included

for CCQM-

ort

ercury for CCi) kg)

d(mg/

24 -0.4

39 -0.0

21 -0.0

19 0.0

40 0.02

35 0.02

15 0.02

65 -0.00

21 -0.0

35 -0.0d in the calcu

-K106. Point

CQM-K106 di /kg)

U((mg

463 0.0

008 0.0

023 0.0

03 0.0

20 0.0

27 0.0

27 0.0

037 0.0

007 0.0

001 0.0ulation of KC

ts show the

Page 19

(di) g/kg)

052

081

047

043

082

073

036

024

047

073 CRV

di, while th

/44

he error barss


8. DISCUSSION

Isotope Dilution Mass Spectrometry (IDMS) has been regarded as having the potential to be a primary method by CCQM since 1995. IDMS is the most accurate analytical method for measurement of trace amount of elements and elemental speciations, and is widely applied to development of CRMs and CCQM comparisons. For CCQM-K106, 6 participants determined Pb and 5 participants determined Hg in the cream sample by means of IDMS. In order to strengthen technological communication and improve measurement level, in this report, we summarized the detailed information relating to determination of Pb by IDMS provided by the participants and shown in Table 15.

Table 15. The details of measurement of Pb in the cream by IDMS

Institute HSA KRISS TÜBITAK UME PTB NIM NIMT

Enriched Isotope spike

206Pb, (Oak Ridge

National Laboratory)

206Pb 206Pb 207Pb, 153-c

(Chemotrade )

207Pb (GBW04442,

NIM) 206Pb

Isotope standard

NIST SRM 981

NIST SRM 981 & 982

NIST SRM 981& 982&991

NIST SRM 981

NIST SRM 981 /

Calibration standard

NIST SRM3128, BAM-Y004

KRISS lead standard solution

NIST SRM 3128

NIST SRM 981 / NIST

SRM 3128

Isotope pair in blend

208Pb/206Pb 208Pb/206Pb 208Pb/206Pb 207Pb/208Pb 207Pb/208Pb 208Pb/206Pb

204Pb/206Pb in cream 0.05461 0.05305 0.0543 0.05425 0.054361 /

207Pb/206Pb in cream 0.85698 0.8452 0.8532 0.851347 0.852901 /

208Pb/206Pb in cream 2.11633 2.075 2.1089 2.103392 2.106851 /

Cblank (mg/kg) / 0.108 / / 0.01 /

Pb (mg/kg) 7.46 7.479 7.55 7.492 7.468 7.62

As we know, there is variation in isotope compositions of Pb in natural terrestrial materials. So it is quite important to measure Pb isotope compositions in a sample for using IDMS method. However, IDMS method involves lots of influential factors and uncertainty sources. Besides Pb isotope ratios in cream sample, other factors also should be taken into account and controlled during the measurement process, such as spike, calibration standard, procedure blank and so on.


9. CONCLUSION

The homogeneity and stability level of Pb, As and Hg in the cream sample can fit the objective of the comparison. With respect to the methodology, most of the participants used microwave digestion methods for sample treatment, and a variety of techniques such as ICP-MS, AAS, INAA were adopted by the participants. For Pb and Hg mesurement, most participants choose ID-ICP-MS method, which showed the better performance in terms of consistency and reliability of the measurement results. Base on different statistic way to calculate the reference mass fraction values and associated uncertainties, the median and uncertainty of median are proposed as the key comparison reference value (KCRV) and its associated key comparison reference uncertainty (KCRU) after removal of suspected extreme values. According to the CCQM Guidance Note [2], the expanded uncertainty of the reference value is calculated as U = 2 × u. In general, the performances of the majority of the CCQM-K106 participants are very good, illustrating their measurement capability for Pb, As and Hg in a complex greasy matrix.

10. ACKNOWLEDGEMENTS The contact persons, analysts and institutes responded to this comparison and contributed their efforts to CCQM-K106&P128.1, are highly appreciated and acknowledged.

Institute Contact persons and/or analysts CENA/USP Elisabete A. De Nadai Fernandes NIS Randa Nasr Ahmed Yamani, Adel B. Shehata BIM Boriana Kotzeva JSI Milena Horvat, Radojko Jacimovic, Majda Pavlin GLHK C K TSANG, Y. P. Tsoi HSA Richard Shin

NIMT Benjamat Chailap , Charun Yafa, Yanee Pharat, Sutthinun Taebunpakul, Nattikarn Kaewkhomdee

INMETRO Rodrigo Caciano de Sena, Marcelo de Almeida

KRISS Yong-Hyeon Yim, Kyoung-Seok Lee, Sook Heun Kim, Jung Ki Suh, In Jung Kim,Youngran Lim, Myung Chul Lim, Hyung Sik Min

VNIIM Leonid Konopelko TÜBİTAK UME Nilgün TOKMAN, Betül ARI PTB Ing.Olaf Rienitz, Reinhard Jaehrling, Carola Pape NIM Jun Wang, Qian Wang

Many thanks for the support and advice from Dr. Mike Sargent, the chairman of CCQM IAWG. 11. REFERENCES [1] International Standards Organization, ISO Guide 35: Reference materials – General and statistical

principles for certification, Geneva, Switzerland, 2006. [2] CCQM Guidance note: Estimation of a consensus KCRV and associated Degrees of Equivalence,

Version: 10, 2013-04-12.


APPENDIX A: DEMONSTRATED INORGANIC CORE CAPABILITIES


Inorganic Core Capabilities Table Report from Participating Institute

CCQM Study: √ CCQM-K106 □ CCQM-P128.1 Institute: GLHK, HSA, INMETRO, KRISS, NIM, NIMT, TÜBİTAK UME, VNIIM Method: ICP-MS (non-ID) Analyte(s): As, Pb Instructions: List element symbols for analytes in the appropriate column (‘Not tested’ or ‘Tested’) for all capabilities relevant to your measurements. Provide a brief explanation of the challenges you encountered in the final column, highlighting any aspects where you believe this measurement presented an unusually high degree of difficulty. Please add rows for any other capabilities which you used but which have not been included in this table.

Capabilities/Challenges Not tested Tested Specific challenges encountered

Contamination control and correction All techniques and procedures employed to reduce potential contamination of samples as well as blank correction procedures. The level of difficulty is greatest for analytes that are environmentally ubiquitous and also present at very low concentrations in the sample.

GLHK(As, Pb), HSA(As), NIMT(As), TÜBİTAK UME(As)

INMETRO(Pb, As), KRISS(As), NIM(As), VNIIM(Pb, As)

Blank correction (NIM) The concentration are relatively high and control of blank was not an issue.(VNIIM)

Digestion/dissolution of organic matrices All techniques and procedures used to bring a sample that is primarily organic in nature into solution suitable for liquid sample introduction to the ICP.

GLHK(As, Pb),HSA(As), NIMT(As), TÜBİTAK UME(As)

INMETRO(Pb,As), KRISS(As), NIM(As), VNIIM(Pb, As)

Microwave digestion (NIM) Digestive reagents: HNO3 are typically employed for the dissolution (NIMT) Microwave acid digestion was used for decomposition of the sample. In some cases organic matrix is not fully digested. (VNIIM)

Digestion/dissolution of inorganic matrices All techniques and procedures used to bring a sample that is primarily inorganic in nature into solution suitable for liquid sample introduction to the ICP.

GLHK(As, Pb),VNIIM(Pb, As)

INMETRO(Pb, As), HSA(As), KRISS(As), NIM(As), NIMT(As), TÜBİTAK UME(As)

Sample digestion requires HF acid for complete dissolution due to the presence of silicone oil in sample.(HSA) A small amount of HF would be necessary to break down the minerals. (NIMT) Sample digestion requires HF for complete dissolution of inorganic matrices. (INMETRO) Requires use of HF acid for complete dissolution of inorganic matrices. (KRISS) HF acid was added in the microwave digestion procedure. (NIM)

Volatile element containment All techniques and procedures used to prevent the loss of potentially volatile analyte elements during sample treatment and storage.

GLHK(As, Pb)， HSA(As), TÜBİTAK UME(As)

INMETRO(Pb, As), KRISS(As), NIM(As), NIMT(As), VNIIM(Pb, As)

Closed vessels were used during sample digestion. (KRISS) Closed vessels were used during microwave-assisted sample digestion. (NIM) The digests solution was immersed in ice for 15



minutes.(NIMT) Vessel cooling to room temperature (VNIIM)

Pre-concentration Techniques and procedures used to increase the concentration of the analyte introduced to the ICP. Includes evaporation, ion-exchange, extraction, precipitation procedures, but not vapor generation procedures.

GLHK(As, Pb), HSA(As), INMETRO(Pb,As), KRISS(As), NIM(As), NIMT(As), TÜBİTAK UME(As), VNIIM(Pb, As)

/ No need (NIMT)

Vapor generation Techniques such as hydride generation and cold vapor generation used to remove the analyte from the sample as a gas for introduction into the ICP.

GLHK(As, Pb), HSA(As), INMETRO(Pb, As), KRISS(As), NIM(As), NIMT(As), TÜBİTAK UME(As), VNIIM(Pb, As)

/ No need (NIMT)

Matrix separation Techniques and procedures used to isolate the analyte(s) from the sample matrix to avoid or reduce interferences caused by the matrix. Includes ion-exchange, extraction, precipitation procedures, but not vapor generation procedures. Techniques and procedures used to isolate the analyte(s) from the sample matrix to avoid or reduce interferences caused by the matrix. Includes ion-exchange, extraction, precipitation procedures, but not vapor generation procedures.

GLHK(As, Pb), HSA(As), INMETRO(Pb, As), KRISS(As), NIM(As), TÜBİTAK UME(As), VNIIM(Pb, As)

NIMT(As) To avoid 40Ar35Cl+ polyatomic interferences, oxygen gas acting as a DRC gas makes it possible to shift analytical m/z 75 (75As+) to m/z 91+ (75As16O). (NIMT)

Calibration of analyte concentration The preparation of calibration standards and the strategy for instrument calibration. Includes external calibration and standard additions procedures.

GLHK(As, Pb), NIMT(As)

HSA(As), INMETRO( Pb, As), KRISS(As), NIM(As), TÜBİTAK UME(As)

Standard addition was used. (HSA) Standard addition method with internal standard was used. (KRISS) Standard addition method with internal standard was used. (NIM)

Signal detection The detection and recording of the analyte isotope signals. The degree of difficulty increases for analytes present at low concentrations, of low isotopic abundance, or that are poorly ionized.

GLHK(As, Pb), HSA(As), TÜBİTAK UME(As), VNIIM(Pb, As)

INMETRO(Pb,As), KRISS(As), NIM(As), NIMT(As)

Reliable analytical signals in low levels of arsenic concentration requires well-organized plan. (NIMT)

Memory effect Any techniques used to avoid, remove or reduce the carry-over of analyte between consecutively measured standards and/or samples.

GLHK(As, Pb),HSA(As), NIMT(As), VNIIM(Pb, As)

INMETRO(Pb,As), KRISS(As), NIM(As), TÜBİTAK UME(As)

Washing procedures with deionized water were inserted between every sample measurements. (KRISS) Washing procedures with 5% HNO3 were inserted between every sample measurements. (NIM)

Correction or removal of isobaric/polyatomic interferences Any techniques used to remove, reduce, or mathematically correct for interferences caused by mass overlap of analyte isotopes with isobaric or polyatomic species. Includes collision cell techniques, high

GLHK(As, Pb), INMETRO(Pb, As)

HSA(As), KRISS(As), NIM(As), NIMT(As), TÜBİTAK

High resolution mass spectrometry was used to remove interferences. (HSA) ICP/MS at high resolution



resolution mass spectrometry, or chemical separations. The relative concentrations and sensitivities of the analyte isotopes and the interfering species will affect the degree of difficulty.

UME(As), VNIIM(Pb, As)

(R≥9000) was used to avoid polyatomic interferences. (KRISS) He reaction gas was adopted to reduce interference of ArCl.(NIM) This experiment was performed with oxygen gas used to avoid the effect of 40Ar35Cl+ polyatomic interferences. (NIMT) Polyatomic interferences were taken into account by the use of the instrument software. (VNIIM)

Correction or removal of matrix-induced signal suppression or enhancement Chemical or instrumental procedures used to avoid or correct for matrix-induced signal suppression or enhancement.

GLHK(As, Pb), KRISS(As)

HSA(As), INMETRO( Pb, As), NIM(As), NIMT(As), TÜBİTAK UME(As), VNIIM(Pb, As)

Standard addition was used to account for matrix effect. (HSA) Standard addition method was adopted to correct possible bias of matrix effect. (NIM) Gravimetric standard addition ICP-MS with an internal standard was used for compensating matrix-induced effect. (NIMT) The addition of the internal standard (Yttrium) was used to take into account the matrix signal. (VNIIM)

Detector deadtime correction Measurement of, and correction for, ion detector deadtime. Importance increases in situations where high ion count rates are encountered.

GLHK(As, Pb), HSA(As), INMETRO(Pb, As), KRISS(As), NIM(As), NIMT(As), TÜBİTAK UME(As), VNIIM(Pb, As)

/ /

Mass bias/fractionation control and correction Techniques used to determine, monitor, and correct for mass bias/fractionation.

GLHK(As, Pb), HSA(As), KRISS(As), NIM(As), NIMT(As)，TÜBİTAK UME(As), VNIIM(Pb, As)

INMETRO( Pb,As)

/



CCQM Study: √ CCQM-K106 □ CCQM-P128.1 Institute: HSA, KRISS, NIM, NIMT, PTB, TÜBİTAK UME Method: ID-ICP-MS Analyte(s): Pb, Hg Instructions: List element symbols for analytes in the appropriate column (‘Not tested’ or ‘Tested’) for all capabilities relevant to your measurements. Provide a brief explanation of the challenges you encountered in the final column, highlighting any aspects where you believe this measurement presented an unusually high degree of difficulty. Please add rows for any other capabilities which you used but which have not been included in this table.

Capabilities/Challenges Not tested Tested Specific challenges encountered Contamination control and correction All techniques and procedures employed to reduce potential contamination of samples as well as blank correction procedures. The level of difficulty is greatest for analytes that are environmentally ubiquitous and also present at very low concentrations in the sample.

HSA(Pb, Hg), NIMT( Hg, Pb)

KRISS(Pb, Hg), NIM(Pb, Hg), PTB(Hg, Pb), TÜBİTAK UME(Pb, Hg)

Blank correction ( NIM)

Digestion/dissolution of organic matrices All techniques and procedures used to bring a sample that is primarily organic in nature into solution suitable for liquid sample introduction to the ICP.

HSA(Pb, Hg), NIMT(Hg, Pb), TÜBİTAK UME(Pb, Hg)

KRISS(Pb, Hg), NIM(Pb, Hg), PTB(Hg, Pb)

Microwave digestion (NIM) Digestive reagents: HNO3 are typically employed for the dissolution. (NIMT)

Digestion/dissolution of inorganic matrices All techniques and procedures used to bring a sample that is primarily inorganic in nature into solution suitable for liquid sample introduction to the ICP.

PTB(Hg, Pb) HSA(Pb, Hg), KRISS(Pb, Hg), NIM(Pb, Hg), NIMT(Hg, Pb), TÜBİTAK UME(Pb, Hg)

Sample digestion requires HF acid for complete dissolution due to the presence of silicone oil in the sample. (HSA) Requires the use of HF for complete dissolution of inorganic matrices. (KRISS) HF acid was added in microwave digestion procedure. (NIM) A small amount of HF would be necessary to break down the minerals. (NIMT)


HSA(Pb), PTB(Hg, Pb), TÜBİTAK UME(Pb, Hg)

HSA(Hg), KRISS(Pb, Hg), NIM(Pb, Hg), NIMT(Hg, Pb)

The isotopic spike was added at the beginning. Once equilibration of spike and analyte isotopes has been achieved, the total recovery of the analyte is not required. (HSA) Closed vessels were used during microwave-assisted sample digestion. (KRISS) Closed vessels were used during microwave-assisted sample digestion. (NIM) The digests solution was immersed in ice for 15 minutes. (NIMT)

Pre-concentration Techniques and procedures used to increase the concentration of the analyte introduced to the ICP. Includes evaporation, ion-exchange, extraction, precipitation procedures, but not vapor generation procedures.

HSA(Pb, Hg), KRISS(Pb, Hg), NIM(Pb, Hg), PTB(Hg, Pb), NIMT(Hg, Pb), TÜBİTAK UME(Pb, Hg)

No need (NIMT)

Vapor generation Techniques such as hydride generation and cold vapor generation used to remove the analyte from the sample

HSA(Pb, Hg), KRISS(Pb), NIM(Pb, Hg),

KRISS(Hg) Cold vapor generation technique was used for Hg measurements. (KRISS)


Capabilities/Challenges Not tested Tested Specific challenges encountered as a gas for introduction into the ICP. PTB(Hg, Pb),

NIMT(Hg, Pb), TÜBİTAK UME(Pb, Hg)

No need (NIMT)

Matrix separation Techniques and procedures used to isolate the analyte(s) from the sample matrix to avoid or reduce interferences caused by the matrix. Includes ion-exchange, extraction, precipitation procedures, but not vapor generation procedures. Techniques and procedures used to isolate the analyte(s) from the sample matrix to avoid or reduce interferences caused by the matrix. Includes ion-exchange, extraction, precipitation procedures, but not vapor generation procedures.

HSA(Pb, Hg), KRISS(Pb, Hg), NIM(Pb, Hg), PTB(Hg, Pb), NIMT(Hg, Pb), TÜBİTAK UME(Pb, Hg)

No need (NIMT)

Spike equilibration with sample The mixing and equilibration of the enriched isotopic spike with the sample.

TÜBİTAK UME(Pb, Hg)

HSA(Pb, Hg), KRISS(Pb, Hg), NIM(Pb, Hg), PTB(Hg, Pb), NIMT(Hg, Pb)

Microwave digestion step was used to facilitate spike equilibration. (HSA) Enriched 200Hg isotope and 206Pb were spiked to sample for applying IDMS. And complete digestion for mixing and equilibration was conducted. (KRISS) Enriched isotope 202Hg and 207Pb were as the spike solutions for IDMS measurement of Hg and Pb respectively. And complete digestion for mixing and equilibration was conducted.(NIM) Allow time for equilibration and perform digestion in the closed system. (NIMT)

Signal detection The detection and recording of the analyte isotope signals. The degree of difficulty increases for analytes present at low concentrations, of low isotopic abundance, or that are poorly ionized.

HSA(Pb, Hg), NIMT(Hg, Pb), TÜBİTAK UME(Pb, Hg)

KRISS(Pb, Hg), NIM(Pb, Hg)，PTB(Hg, Pb)

/


HSA(Pb)，PTB(Hg, Pb), NIMT(Hg, Pb)

HSA(Hg), KRISS(Pb, Hg), NIM(Pb, Hg)，TÜBİTAK UME(Pb, Hg)

For Hg analysis, the wash time was increased and 5% HCl solution was used to wash. (HSA) Washing procedures with deionized water were inserted between every sample measurements. (KRISS) Washing procedure with 5% HNO3 was inserted between every sample measurement. (NIM) Especially for mercury measurement, between the runs (sample blends and solutions for mass bias correction) the lines are washed with 2% percent HNO3 containing 1mg/l Au solution to remove memory effect. Before each ratio measurement, 2 % HNO3 (ultrapure) solution were checked to keep memory effect under control. (TÜBİTAK UME)

Correction or removal of isobaric/polyatomic interferences Any techniques used to remove, reduce, or mathematically correct for interferences caused by mass overlap of analyte isotopes with isobaric or polyatomic species. Includes collision cell techniques, high resolution mass spectrometry, or chemical separations. The relative concentrations and sensitivities of the

HSA(Hg), KRISS(Pb, Hg), NIM(Pb, Hg), NIMT(Hg, Pb)

HSA(Pb)，PTB(Hg, Pb)，TÜBİTAK UME(Pb, Hg)

Possible interference includes 204Hg on 204Pb (corrected by measuring 202Hg). (HSA) This experiment was performed without any gases used for minimize is obaric/polyatomic


Capabilities/Challenges Not tested Tested Specific challenges encountered analyte isotopes and the interfering species will affect the degree of difficulty.

interferences, so standard mode was employed instead. (NIMT)

Detector deadtime correction Measurement of, and correction for, ion detector deadtime. Importance increases in situations where high ion count rates are encountered.

KRISS(Pb, Hg), NIM(Pb, Hg)，PTB(Hg, Pb), NIMT(Hg, Pb)

HSA(Pb, Hg)，TÜBİTAK UME(Pb, Hg)

Sample and calibration blends intensities were matched to reduce the significance of this effect. (HSA)

Mass bias/fractionation control and correction Techniques used to determine, monitor, and correct for mass bias/fractionation.

PTB(Hg), NIMT(Hg, Pb)

HSA(Pb, Hg), KRISS(Pb, Hg), NIM(Pb, Hg)，PTB(Pb)，TÜBİTAK UME(Pb, Hg)

Sample and calibration blends were bracketed with a standard solution with known isotopic composition to correct for mass bias. (HSA) Mass bias/fractionation was corrected for by bracketing correction using an isotope ratio standard. (KRISS) Mass bias was corrected by using bracketing correction with an isotope ratio standard. (NIM)

Spike calibration Techniques used to determine the analyte concentration in the enriched isotopic spike solution.

PTB(Hg, Pb), NIMT(Hg, Pb)

HSA(Pb, Hg), KRISS(Pb, Hg), NIM(Pb, Hg)，TÜBİTAK UME(Pb, Hg)

Exact-matching IDMS was used. (HSA) Double isotope dilution technique was used. (KRISS) Double isotope dilution technique was used. (NIM) Double IDMS has been applied using NIST 3128 for lead measurement since absence of well characterized enriched isotopic reference material. (TÜBİTAK UME)



CCQM Study: √ CCQM-K106 □ CCQM-P128.1 Institute: NIS, VNIIM, JSI, NIM Method: AAS, AAS(DMA) Analyte(s): Pb, As, Hg Instructions: List element symbols for analytes in the appropriate column (‘Not tested’ or ‘Tested’) for all capabilities relevant to your measurements. Provide a brief explanation of the challenges you encountered in the final column, highlighting any aspects where you believe this measurement presented an unusually high degree of difficulty. Please add rows for any other capabilities which you used but which have not been included in this table.

Capabilities/Challenges Not tested Tested Specific challenges encountered Contamination control and correction All techniques and procedures employed to reduce potential contamination of samples as well as blank correction procedures. The level of difficulty is greatest for analytes that are environmentally ubiquitous and also present at very low concentrations in the sample.

NIS(Pb,As,Hg),VNIIM(Hg), JSI(Hg), NIM(Hg)

The contamination from acid reagents is high due to the lack of purity. (NIS) The concentration are relatively high and control of blank was not an issue. (VNIIM) All using materials (solvents, reagents, glassware, etc.) must be demonstrated to be free from interferences under the conditions of the analysis by analysing blanks. (JSI) Blank correction (NIM)

Digestion/dissolution of organic matrices All techniques and procedures used to bring a sample that is primarily organic in nature into solution suitable for liquid sample introduction to the ETA-AAS.

JSI(Hg), NIM(Hg)

NIS(Pb,As,Hg), VNIIM(Hg)

The possibility to get the element free from the organic matrix was difficult due to loss possibilities during digestion. (NIS) Microwave acid digestion was used for decomposition of the sample. In some cases organic matrix is not fully digested. (VNIIM)

Digestion/dissolution of inorganic matrices All techniques and procedures used to bring a sample that is primarily inorganic in nature into solution suitable for liquid sample introduction to the ETA-AAS.

VNIIM(Hg), JSI(Hg), NIM(Hg)

/ /


JSI(Hg), NIM(Hg)

NIS(Pb,As,Hg), VNIIM(Hg)

Vessel cooling to room temperature (VNIIM) - Carefully preparation (weighing of sample, sample handling) - Samples stored in dry place at room temperature (JSI).

Pre-concentration Techniques and procedures used to increase the concentration of the analyte introduced to the ETA-AAS. Includes evaporation, ion-exchange, extraction, precipitation procedures, but not vapor generation procedures.

VNIIM(Hg) , JSI(Hg), NIM(Hg)

NIS(Pb, As), /

Matrix separation Techniques and procedures used to isolate the analyte(s) from the sample matrix to avoid or reduce interferences caused by the matrix. Includes ion-exchange, extraction, precipitation procedures, but not vapor generation procedures.


NIS(Pb, As) Matrix independent(JSI)

Hydride preconcentration/matrix separation of volatile species. Coupling of a hydride system to the ETA-AAS and optimization of conditions.


NIS(Hg) /


Capabilities/Challenges Not tested Tested Specific challenges encountered Calibration of analyte concentration The preparation of calibration standards and the strategy for instrument calibration. Includes external calibration and standard additions procedures. Also use of matrix-matched standards to minimize effect of interferences.

VNIIM(Hg) NIS(Pb,As,Hg),JSI(Hg), NIM(Hg)

Calibration standards were used for instrument calibration. (JSI) The related CRM was used to calibrate measurement results.(NIM)

Signal detection The detection and recording of the absorption signals of analytes. The degree of difficulty increases for analytes present at low concentrations, of low atomic absorption coefficient. Requires selection of operating conditions such as light source, absorption line, Zeeman background correction conditions. Includes selection of signal processing conditions (peak area or height).

VNIIM(Hg), NIM(Hg)

NIS(Pb,As,Hg),JSI(Hg)

- Mercury detection system: Single-beam spectrophotometer with sequential flow through two measurement cells - Light source: low pressure mercury vapour lamp (wavelength: 253.65 nm) - Detector: UV Enhanced Photodiode Detectors (JSI)


VNIIM(Hg) NIS(Pb,As,Hg),JSI(Hg) , NIM(Hg)

After each sample or after two replicates blank was measured (mercury vapour may remain in the decomposition tube, amalgamator, or absorbance cells and be released in a subsequent analysis resulting in a positive bias) (JSI). Measured necessery blank samples before cosmetic sample measured(NIM).

Optimization of the furnace temperature program Optimization of temperature and duration of steps for sample drying, pyrolysis to remove (residual) organics, and atomization. Furnace temperature program to minimize analyte loss in the drying/pyrolysis steps, while maximizing analyte vaporization in the atomization step.

VNIIM(Hg) NIS(Pb, As), JSI(Hg) , NIM(Hg)

- Drying temperature: 200 °C - Drying time: 120 s - Decomposition temperature: 750 °C - Decomposition time: 180 s (JSI) Though adjusting drying temperature , time and decomposition temperature to make mercury vapor is separated from other decomposition materials totally. (NIM)

Correction or removal of matrix effects or interferences Chemical or instrumental procedures used to avoid or correct for spectral and non-spectral interferences. Includes effects of differences in viscosity and chemical equilibrium states of analyte between the standard and sample. Selection of matrix modifier to adjust volatility of analyte and/or matrix to eliminate these effects is also included. Addition of reactive gases (eg oxygen) to the carrier gas to improve matrix separation. Also included is Zeeman or other background correction techniques to remove interference due to absorption and scattering from coexisting molecules/atoms in the sample.

VNIIM(Hg), NIM(Hg)

NIS(Pb,As,Hg), JSI(Hg)

- Interference filter: 254 nm, 9 nm bandwidth - Decomposition in an oxygen environment (oxygen should be pure and mercury free) (JSI)


Inorganic Core Capabilities Table

Report from Participating Institute CCQM Study: √ CCQM-K106 □ CCQM-P128.1 Institute: KRISS, JSI Method: INAA Analyte(s): As Instructions: List element symbols for analytes in the appropriate column (‘Not tested’ or ‘Tested’) for all capabilities relevant to your measurements. Provide a brief explanation of the challenges you encountered in the final column, highlighting any aspects where you believe this measurement presented an unusually high degree of difficulty. Please add rows for any other capabilities which you used but which have not been included in this table.

Capabilities/Challenges Not tested Tested Specific challenges encountered Sample preparation Procedures used to prepare samples for irradiation; determination of the mass basis (e.g., determination of dry mass basis); procedures to minimize sample loss during preparation; procedures to minimize contamination with the elements of interest (highest difficulty for determination of low levels of elements that are ubiquitous in the sample preparation environment).

/ KRISS(As), JSI(As)

Samples were homogenized and taken on a clean filter paper in a way to minimize volatile loss of mass. Sampling and drying has been carried out in a clean-bench to minimize contamination. (KRISS) Aliquots of about 0.24-0.27 g of the CCQM-K106 cream (Vial No. 7) were sealed into pure polyethylene ampoules. One blank polyethylene ampoule was prepared in the same way. No determination of dry mass was applied.(JSI)

Standards preparation Procedures used to prepare element standards or other comparators used for standardization. (e.g., low difficulty for use of pure elements or compounds; higher difficulty for procedures involving dissolution and dilution, or dilution with solid matrices.)


IRMM-530R Al-0.1%Au alloy in form of foil with thickness of 0.1 mm was used. Discs of about 6 mm diameter were prepared. (JSI)

Determination of peak areas (complex spectra/small peaks) Procedures used to determine peak areas. (e.g., high difficulty for small peak areas on complex backgrounds or determination of areas for multiple unresolved peaks.)


The HyperLab program was used for net peak area evaluation in the gamma spectrum. No difficulties were observed in the net peak area determination of As-76 at 559.1 keV.(JSI)

Correction for spectral interferences Procedures used to determine peak areas from interfering nuclides and subtraction of the appropriate number of counts from the peak of interest. Level of difficulty increases with the number of corrections needed and the magnitude of the corrections relative to the total peak area.


No corrections were applied. (JSI)

Corrections for gamma-ray attenuation Procedures used to correct for differences in gamma-ray attenuation between samples and standards; typically relevant only for high-z sample or standard matrices and where samples and standards differ. Level of difficulty increases with the magnitude of the correction.


The same cellulose filter paper materials were used in the preparation of samples and standard comparators using the same procedure to minimize matrix effect due to differential gamma-ray attenuation. (KRISS) Corrections for gamma-ray attenuations in sample/standard were calculated by Kayzero for Windows (KayWin®) software via effective solid angle calculations.


Capabilities/Challenges Not tested Tested Specific challenges encountered Different measuring distances from the top of an HPGe detector for sample and standard can be used due to absolutely calibrated HPGe detector. (JSI)

Corrections for neutron absorption or scattering differences between samples and standards Procedures used to correct for differences between neutron exposure of samples and standards associated with differences in the absorbing and scattering power; e.g., corrections derived from measurements of different amounts of materials or thicknesses of materials, or calculations based on cross-section values to correct for neutron attenuation. Level of difficulty increases with the magnitude of the correction.


The same cellulose filter paper materials were used in the preparation of samples and standard comparators using the same procedure to minimize matrix effect due to differential neutron absorption and scattering. (KRISS) Samples and standards (Al-0.1%Au IRMM-530R) were stacked together and fixed in a polyethylene ampoule in sandwich form and irradiated for about 12 hours in the carousel facility of TRIGA reactor. Standard Al-0.1%Au (nuclide Au-198 (T1/2=2.695 d) at gamma line of 411.8 keV) was used for axial flux gradient corrections in the sample. Radial flux gradient is negligible due to similar diameter of sample and standard. Thermal and epithermal self-shielding factors are equal to 1.(JSI)

Corrections for sample and standard geometry differences Procedures used to determine correction factors for differences in sample and standard irradiation and counting geometries. These may include, e.g., use of flux monitors to determine irradiation geometry correction factors, and calculated correction factors based on measured thicknesses and sample-to-detector distances. Level of difficulty increases with the magnitude of the correction.


Neutron flux monitors were bracketed next to each samples and standards for geometry-dependent correction of neutron fluence. (KRISS) Differences in sample/standard geometry are taken into account and they are calculated by Kayzero for Windows (KayWin®) software, which was used for effective solid angle calculations and elemental concentration calculations.(JSI)

Corrections for differences in neutron exposure of samples and standards For some NAA applications, samples and standards are irradiated individually and corrections are needed for any differences in neutron exposures. Corrections may be based on, e.g., results from flux monitors or estimates based on knowledge of the facility.

KRISS(As) JSI(As) Based on standard k0-INAA procedure only axial flux gradient corrections in the sample were applied. For flux monitor radionuclide Au-198 (from standard Al-0.1%Au) was used. (JSI)

Corrections or uncertainty assessments for high count rates Procedures used to correct for losses in the analyzer due to high count rates; e.g., set up and validation of loss-free counting hardware, use of mathematical corrections for pulse pileup as a function of analyzer dead time, etc. Level of difficulty increases with the magnitude of the correction.


Measurements were carried out at such distances that the dead time was kept below 10 % with negligible random coincidences. Multichannel analyzer DSPECPLUSTM in ZDT mode was used. (JSI)

Contamination Control Prior to irradiation, any additional sample preparation procedures used to minimize potential for contamination with elements of interest (highest difficulty for determination of low levels of elements that are ubiquitous in the sample preparation environment).


One blank polyethylene ampoule prepared in the same way and irradiated with samples. The study shows that no As was present in the blank.(JSI)

Pre-irradiation treatment or post irradiation dissolution May include but are not limited to, e.g.:

KRISS(As), JSI(As)

/ /


Capabilities/Challenges Not tested Tested Specific challenges encountered Procedures such as fusion, wet ashing, combustion or other methods used to separate the elements of interest prior to irradiation; Addition and equilibration of carriers; Digestion procedures used to obtain quantitative dissolution; Procedures to minimize loss of volatile elements during the above. Radiochemical separations May include but are not limited to, e.g.: Procedures used to separate the element or elements of interest post irradiation and post dissolution; these may include ion exchange separation, liquid extractions, wet chemical procedures, quantitative precipitation, etc. Procedures used to determine radiochemical yields.

KRISS(As), JSI(As)

/ /


APPENDIX B: INVITATION, TECHNICAL PROTOCOL AND REPORTING FORMS


CCQM-K106 & P128.1 Pb, As and Hg measurements in cosmetic (cream)

Invitation to participate Dear Colleagues, We kindly invite you to participate in the key comparison CCQM‐k106 or the pilot study CCQM‐P128.1 “Pb, As and Hg measurements in cosmetic”. Cosmetics are used of practically all walks of life as a means of improving skin and beautifying complexion. In recent years, more and more attention has been paid to the cosmetic safety. In response to cosmetic safety issue, the accurate measurement of heavy metals in cosmetic is particularly important. On the basis of CCQM‐P128 pilot study, the key comparison CCQM‐K106 and the parallel pilot study CCQM‐P128.1, Pb, As and Hg in cosmetic material, will be carried out in this year, which is expected to support CMC claiming relating to inorganic elements in cosmetic materials and similar chemical industry products. The candidate material for the CCQM‐K106 & P128.1 is cream, which is similar with the CCQM‐P128 sample. The homogeneity and stability level of the material fit the objective of the comparison. For this comparison, each participant will receive two numbered bottles, each of which contains about 5g sample. The measurands are Pb, As and Hg in cosmetic (cream). Participants are allowed to measure all three elements or any one of their interest. All related detailed information can be found in the technical protocol. Organizations which are a national measurement institute (NMI), or an appropriate designated institute in accordance with the CIPM MRA, are eligible to participate in the key comparison or pilot study. Other expert laboratories, from countries that are members of the Metre Convention, may also participate in the pilot study provided that their contribution has added scientific value or where they may qualify later as a designated institute in the field under study. Expert laboratories which respond to this invitation are requested to inform their national measurement institute of their participation in the pilot study and to advise the co‐ordinating laboratory of the appropriate contact at their NMI. The IAWG Chairman will be asked to formally notify each relevant NMI of the participation by an expert institute from their country. Expert laboratories participating in the study will be required to provide a written assurance that they will not use the results for any commercial purpose and will not publish information about the study in any form without the written agreement of the IAWG Chairman. Registration deadline will be 31 May 2013. The samples will be dispatched in June 2013, and the deadline for reporting results is 15 December 2013. Results of this comparison will be presented at the CCQM IAWG meeting in April 2014. If you are interested in participating in CCQM‐k106 or CCQM‐P128.1, please fill in the Registration Form and email to [email protected] before 31 May 2013. Best regards,

Dr. Wang Jun

Program Coordinator


CCQM-K106& P128.1

Pb, As and Hg measurements in cosmetic (cream)

Technical Protocol

1. Introduction

Nowadays, the cosmetics (e.g. lightening cream or lotion, moisturising cream, anti-wrinkle cream, beauty masks etc.) are regarded as a means of improving the skin and beautifying the complexion is well established. They are commonly used of practically all walks of life.

It is acknowledged that heavy metal impurities in cosmetic products are unavoidable due to the ubiquitous nature of these elements, but should be removed wherever technically feasible. There has been several legislation or standard such as cosmetics directive 76/768/EEC, ISO22716:2007 etc. available now. Different countries have also established relevant domestic regulations or guidelines. For instance, in China, hygienic standard for cosmetics regulates the heavy metal contents in products. The regulated mass fractions (w) are w ≤40 mg⋅kg-1 for Pb, w ≤10 mg⋅kg-1 for As，w ≤1 mg⋅kg-1 for Hg respectively in cosmetic products. However, in order to achieve “magic” whiten or anti-aging effects and prevent the product formulations from alteration and degradation, some additives, such as heavy metals (Pb, As, Hg) and preservatives are added on purpose in some cosmetic products. As a result, more and more attention has been paid to the cosmetic safety.

In response to cosmetic safety issue, the accurate measurement of the heavy metals in cosmetic is, therefore, particularly important. NMIs from different countries should establish their chemical metrology traceability system in this area, which include both measurement methods research and certain CRMs development. It should be noted that because the matrix of many cosmetics are complex and the contents of the heavy metals are relatively low, it is a challenging task to measure analytes with high accuracy and precision. From 2010 to 2011, CCQM-P128 (Pb, As measurements in cosmetic) was carried out successfully, which was the first pilot study relating to measurement of heavy metals in cosmetic material. 13 institutes submitted their measurement reports, and the performances of majority of the participants were very good.

On the basis of CCQM-P128 pilot study, the key comparison CCQM-K106 and the parallel pilot study CCQM-P128.1, Pb, As and Hg in cosmetic material, will be carried out in 2013.In this comparison, the test material is similar to the sample of CCQM-P128, which is a basic cream matrix includes pure water, liquid paraffin, silicone oil, synthetic squalane, hyaluronic acid, glycerin, propylene glycol, allantoin, preservative and so on. The comparison is to ensure the comparable and traceable measurement results for Pb, As and Hg in cosmetic products among the NMIs and other designated measurement bodies worldwide. The results of CCQM-K106are expected to cover the measurement capability and support CMC claiming for inorganic elements in the similar cosmetic materials, chemical industry products and the relative highly concentration of grease.


2. Samples

The cosmetic (cream) sample was prepared under the guidance of professional technicians. The formula of the cream was carefully chosen by the professional technicians, and quite matched with a real cosmetic. Raw materials were heated and mixed, the appropriate amount of HgCl2, Pb(NO3)2 and Na3AsO4 solutions were added into aqueous phase, and then emulsified, homogenized with violently stirring. After pre-homogeneity investigated, it was packaged into clean brown glass bottles covered with a PE/butyl rubber stopper sealed with aluminium crimp tops. Each unit was vacuum packed in aluminium-nylon pouch.

The homogeneity of Pb and As in the sample were tested by ICP-MS after microwave digestion of samples, and the sampling weight is about 0.3g; the homogeneity of Hg was tested by a direct mercury analyzer, and the sampling weight is about 0.1g. No statistically significant heterogeneity was found based on F test.The stability of Pb, As and Hg in the sample were investigated, includingstorage at room temperature for more than one year and at 48℃and -20℃ for one week respectively. The results show that the stability level of this cream material fit the objective of the comparison.

3. Measurands

Lead, Arsenicand Mercury in cosmetic (cream). The approximate levels of the concentrations are:Pb: (5~10)mg/kg; As: (1~10)mg/kg;Hg: (0.1~2)mg/kg

4. Measurement method Participants may use any appropriate method(s) of their choice.

Core capability The potentially interferes resulting from the complicated matrix make it a tough job even for the determination of the common elements in the cosmetics including Pb, As and Hg. The core capabilities demonstrated in this comparison focus on the following aspects. Firstly, the organic components matrices in the cosmetic sample should be considered carefully in the sample pre-treatment procedure. Secondly, methodologies established would focus on the different aspects during measurement. For example, more attentions should be paid for spike equilibration with the sample, matrix influence and accurate measurement of isotopic ratios for the IDMS method. For external standard calibration method, the standard (working) curves and the selection of the internal standard should be key steps. If the AAS and ICP-OES methods are used, the matrix interference and the pre-concentration procedure should be taken into consideration. Thirdly, for methods validation, it is the best choice to be conducted it through the analysis of a certified reference material. However, there are few available cosmetic matrix CRMs. The last resort is an attempt to establish accuracy through spike recovery experiments and/or the use of standard additions.

5. Distribution Each participant will receive two numbered bottle containing 5g samples in each bottle. Participants will be informed the date of samples dispatching. Participants are required to


confirm the receipt of the sealed samples, to fill in the return receipt table and send it to the coordinator by e-mail or fax. If there is any damage, please contact us immediately and NIM will mail out another one.

6. Handling and storing instructions To avoid any decomposition and losing of water content, the samples should be kept sealed until they are used. They should be stored at room temperature (18～25℃) in its original bottle, capped tightly and not exposed to intense direct light and ultraviolet radiation. Sample should be carefully opened for analysis in a short period of time to avoid contamination. An injector is recommended to use for sampling.

7. Time schedule Call for Participation: April 2013 Deadline for registration: May 31, 2013 Dispatch of the samples: June 2013 Deadline for receipt of the result report: December15, 2013 Discussing of the result: CCQM/ IAWG Paris meeting of 2014 8. Registration Please complete the registration form and return it to [email protected] Please register no later than 31 May 2013. 9. Reporting A suggestion for a summary report table will be sent to the participants by email while the samples are dispatched. The report should be submitted before 15 December 2013. NIM will confirm the receipt of each report. The report should include the following aspects:

A final result and uncertainty evaluation. The results will be reported as mass faction [mg/kg]. At least 6 independent determinations should be performed for each element.

Please note that only one result from each institute will be considered for calculation of the KCRV of each element.

A detail description of the applied method of measurement. If more than one method were applied, a detail description must be given for each method.

Information about sample digestion and preparation. Information about the reference material used for calibration (origin, standard value,

standard uncertainty and isotopic ratio if necessary) or other materials used in the analytical procedure.

Information about the uncertainty of measurement. The uncertainty should be evaluated according to the ISO Guide to the Expression of Uncertainty in Measurement, 1993. It should include: - The complete specification of the measurement equation including corrections e.g. for

blanks and interferences. - The identification and quantification of all uncertainty sources. - The combined standard uncertainty. - The value for the coverage factor and the expanded uncertainty.


Filled Core capability tables related to the measurement methods used by participants. 10. Participation

National metrological institutes (NMIs), or an appropriate designated institute in accordance with the CIPM MRA, are welcome to participate in the key comparison CCQM-K106 or the pilot studyCCQM-P128.1. Other expert institutes from countries that are members of the Metre Convention are also invited to participate in the pilot study.

Coordinating laboratory and contact person Dr. Wang Jun National Institute of Metrology (NIM) No. 18, Bei San Huan Dong Lu, Chaoyang District Beijing, 100013 P.R.China Tel: +86 10 84251244 Fax: +86 10 64271639 Email: [email protected]


CCQM-K106 & P128.1 Pb, As and Hg measurements in cosmetic (cream)

Results Report

Please return this results report by 15 December, 2013

NAME : INSTITUTE : DEPARTMENT : ADDRESS : COUNTRY : TEL : FAX : E-MAIL : Report your results and uncertainties in mass fraction using the units [mg/kg] in the table below. Details concerning analysis of replicates, details of method, calculation of results, and associated uncertainties should be given in the following pages of your report.

Analyte Unit Mass fraction (combined) standard

uncertainty

Expanded uncertainty

k

As mg⋅kg-1

Pb mg⋅kg-1

Hg mg⋅kg-1

If the final result has been calculated from more than one method, the individual results from the contributing methods must also be reported. Determination method used for each analyte: Sample preparation: DATE:

SIGNATURE:


Additional information

Results for the analysis of replicate samples：

Determination As (mg⋅kg-1) Pb (mg⋅kg-1) Hg (mg⋅kg-1) Vial No.

1

2

3

4

5

6

Report at least 6 replicates for each analyte. If more than 6 determinations are carried out, please

insert more lines.

Uncertainty evaluation:

Parameter Source of uncertainty Value (xi)

Unit Standard

uncertainty u(xi)

Type (A/B)


Method(s) used for As, Pb and Hg analysis

Further information and details can be added in pages below, or in a separate report if preferred.

If you use a separate report, please provide a complete description of the method(s) used for the

determination, including the following information as appropriate:

A detail description of the applied method of measurement. If more than one method were

applied, a detail description must be given for each method.

Information about sample digestion and preparation.

Information about the reference material used for calibration (origin, standard value,

standard uncertainty and isotopic ratio if necessary) or other materials used in the analytical

procedure.

Information about the uncertainty of measurement. The uncertainty should be evaluated

according to the ISO Guide to the Expression of Uncertainty in Measurement, 1993. It

should include:

- The complete specification of the measurement equation including corrections e.g. for

blanks and interferences.

- The identification and quantification of all uncertainty sources.

- The combined standard uncertainty.

- The value for the coverage factor and the expanded uncertainty.

Filled Core capability tables related to the measurement methods used by participants.


Description of method

Brief outline, the basis of choice of your method, from open literature, ISO, national standard.

Sample digestion and preparation

- Weight taken:

- Digestion conditions including acids or other reagents used, digestion mode and time:

- Procedure for digest handling and preservation:

- Other sample preparation techniques:

Measurement procedure

(e.g. ICP-MS method):

- Conditions used:

- Instrument used:

- Type of calibration: IDMS [ ]; External calibration [ ]; Standard addition [ ]

- one-point [ ]

- two-point [ ]

- multi-point [ ]

- Calibration standard(s) used:

- Source, purity and uncertainty of standard(s):


For IDMS, the isotope composition of Pb and Hg in the cream are measured or not

Yes [ ]; No [ ]

If measured, the measurement results:

Quality control or method validation

- Use of CRM, Control sample, and other:

Differences (if any) in the method(s) used from the information given on page 4

Any problems experienced in analysing the sample

Other comments about the sample

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