CCQM-K113 final report. Noble gas mixture

Transcription

1 CCQM-K113 final report Noble gas mixture Jeong Sik Lim 1, Jinbok Lee 1, Dongmin Moon 1, James Tshilongo 1,, Jeongsoon Lee 1, Han Qiao, Hu Shuguo, Zhang Tiqiang, Michael E. Kelley 3, George C. Rhoderick 3, L.A. Konopelko 4, A.V. Kolobova 4, I.I. Vasserman 4, S.V. Zavyalov 4, E.V. Gromova 4, O.V. Efremova 4 1 Korea Research Institute of Standards and Science (KRISS), Division of Metrology for Quality Life, Yuseong-gu, Daejeon, 31143, Republic of Korea National Institute of Metrology (NIM), 18 Beisanhuan Donglu, Beijing , P.R.China 3 National Institute of Standards and Technology (NIST), Chemical Science and Technology Laboratory, 100 Bureau Drive, Gaithersburg MD, USA 4 D.I. Mendeleyev Institute for Metrology, Rostekhregulirovaniye of Russia (VNIIM), Department of State Standards in the field of Physical Chemical Measurements, 19 Moskovsky Prospekt, St-Petersburg, Russia Current address: National Metrology Institute of South Africa (NMISA), Gas Analysis Group, Brummeria Pretoria 018, Lynwood Ridge, 0040, South Africa Field Amount of substance Subject Noble gas mixture Participants KRISS, NIM, NIST, VNIIM Organizing body CCQM GAWG

2 Table of Contents Introduction 1 Supported claims 1 Participants 1 Schedule 1 Comparison protocol Measurement Standards 4 Measurement equation 4 Measurement methods 6 Degrees of equivalence 7 Measurement s 8 Conclusion 11 References 11 Appendix 1

3 Introduction Noble gas standards are important in different industries such as light bulbs industry, automotive industry, space industry, lasers industry and also in plasma display panel manufactured as well as other semiconductor manufacturing industries. Thus, providing high accuracy certified reference material of mixed noble gases to those industries has become more important as those industries are growing. Supported claims This key comparison will support the measurement capabilities, which can be used to support Calibration and Measurement Capabilities (CMC) claims, for the mixture of Xenon, Krypton, Neon, Argon and Helium from 1 mmol/mol to 960 mmol/mol. In case of partial participation, CMC claims should be adjusted accordingly. Participants A total of four Consultive Committee of Amount of Substances (CCQM) members took part in this key comparison under auspices of the International Committee for Weights and Measures - Mutual Recognition Arrangement (CIPM-MRA). The participants are listed in Table 1. Table 1: List of participants Acronym Country Institute KRISS KR Korea Research Institute of Standards and Science, Daejeon, Republic of Korea NIM CR National Institute of Metrology, Beijing, P.R.China NIST US National Institute of Standards and Technology, Gaithersburg, United States of America VNIIM RU D.I. Mendeleyev Institute for Metrology, St. Petersburg, Russia Schedule Table : Key comparison schedule of CCQM-K113 1

4 January 014 March 014 September - November 014 December February 015 March 015 April 015 April 016 Event Registration and protocol circulation Preparation and verification of mixtures Shipment of cylinders from KRISS Measurements and reporting Return of cylinders to KRISS Second verification measurements Draft A report Comparison protocol A set of mixtures of measurands with the nominal mole fractions listed in Table 3 was prepared by gravimetry. The filling order to the evacuated cylinder (Al, 10 dm 3 ) is Xe, Kr, Ne, Ar and He of which impurities were assessed by various analytical systems. The noble gas mixtures were verified by GC-TCD. The amount of substance fractions were adopted as a key comparison reference value (KCRV). Table 3: Nominal amount-of-substance fractions Amount-of-substance fraction x (%mol mol -1 ) Helium Balance Argon 0 Neon 10 Krypton Xenon 1 The pressure of the cylinder was approximately 10 MPa; aluminum cylinders of 10 dm 3 (Luxfer Co.) were used. Each cylinder was assigned by its own reference value. Participating laboratories were requested to specify in detail which analytical method(s) were used and how the evaluation of measurement uncertainty was performed.

5 Each participating laboratory was responsible for the calibration of its own instrument(s). Calibration method to be applied for the concentration assignment of key comparison cylinder must be well established and reported to KRISS. This is an absolute necessity for proper evaluation of the data. After calibration, the measurements of the gas mixtures must be recorded. Each laboratory was required to express the uncertainty on all results submitted, as expanded uncertainty. The evaluation of measurement uncertainty should be in accordance to the Guide to the expression of uncertainty in measurement (ISO GUM). The participants should provide a detailed description of the uncertainty budget, including - Method of evaluation (type A or B) - (assumed) probability distribution - Standard uncertainties - (effective) degrees of freedom (if applicable/used) - (statistical) reasoning behind the coverage factor. After the measurements, the participants are responsible for return shipment of the cylinders leaving a sufficient amount of gas for reanalysis. The measurement report requires at least three independent measurements per cylinder, obtained under repeatability conditions, e.g. calibration (S) measurement (A) calibration (S) measurement (A) calibration (S) measurement (A) calibration (S) (etc.). This was a strict requirement to come to proper statistical analysis of the reported data. One single measurement result is usually obtained from multiple readings (sub measurements), without recalibrations. Its standard deviation provides information about the performance of the measurement system. Additional measurement reports and additional information can be submitted jointly with the report form to the KRISS and will be taken into consideration during the evaluation. 3

6 Measurement standards Gas mixtures distributed to the participants were prepared by gravimetric method in accordance with ISO 614:001. [1] For purity analysis of parent gases, various analytical systems were used. For instance, GC(-Methanizer)-FID was used for CO, CH4, CO and THCs. The PDD, AED and TCD were used for H, N, O and Ar. For the separation of O and Ar, column oven was cooled by LN. Otherwise, dedicated analyzers such as magnetic sector type mass spectrometer and O analyzer were used for respective analysis of O and Ar. A dew point meter was served as a moisture analyzer. In particular, the quantification of other noble gas impurities in the raw gases was very carefully carried out by using the LN-cooled GC-TCD and the magnetic sector type mass spectrometer. Significant amount of noble gas impurities biasing the final mixing ratios of the gravimetric cylinders were not detected. A filling order to evacuated clean cylinder was Xe Kr Ne Ar He, which is ascending order of partial pressure. The amount-of-substance fractions as obtained from the gravimetry and the purity analysis of the parent gases were used as reference values. Accordingly, each cylinder has its own reference value. The measurement standards were verified with the GC-TCD against a Primary Standard Material (PSM). It should be noted that linear response of each analyte is confirmed over concentration ranges covering that of distributed KC cylinders. The sensitivities were then compared to give the verification uncertainties less than 0.05 % over every components. Measurement equation The reference values used in this key comparison are based on the gravimetry and the purity assessment of the parent gases. Verification of the composition of all KC cylinders had been performed before shipping out. After return of the cylinders, another verification was performed to check the stability of those. In the preparation, the following uncertainty components have been considered [] : 1. Gravimetric preparation (weighing process) (xi,grav). Purity of the parent gases (Δxi,purity) 3. Stability of the gas mixture (Δxi,stab) 4

7 The amount of substance fraction xi,prep of a particular component in mixture i, as it appears during use of the cylinder, can be expressed as x i,prep = x i,grav + x i,purity + x i,stab (1) Assuming that the terms in equation (1) are independent from each other, the expression of the standard uncertainty combines as follow u i,prep = u i,grav + u i,purity + u i,stab. () Long-term stability test showed that x i,stab = 0 associated with u i,stab = 0 (3,4) Here, it should be noted that analytical error (e.g. drift, calibration, repeatability and etc..) is dominant over an uncertainty of the long-term stability. Therefore, the uncertainty regarding long-term stability was set to 0. Equation (1) then reduces to give follows x i,prep = x i,grav + x i,purity associated with u i,prep = u i,grav + u i,purity. (5,6) The validity of the gravimetric preparation for the KC cylinders was checked by verification test according to ISO 6143:001. [] Based on the assumption that preparations and measurements are not biased, the following condition should be met [,3] x i,prep x i,ver u i,prep + u i,ver (7) where xi,ver is the mole fraction of particular component assigned by the verification measurement and ui,ver is its associated standard uncertainty. The factor is a coverage factor. Recall that whatever quantity, q, can be expressed by the expectation value and signed deviation as like <q> + δq. [3] The reference value of mixture i can then be expressed as follows [] 5

8 x i,ref = x i,ref + δx i,ref, where x i,ref = x i,prep + x i,ver (8,9) where Δxi,ver is the correction resulting from the verification. Once verification criteria was satisfied within an uncertainty of verification measurement ui,ver, due to no correction from verification, the expectation of the correction <Δxi,ver> is 0. Thus, (8,9) can be expressed as x i,ref = x i,prep + δx i,prep + δ x i,ver. (10) Therefore, the reference value xi,ref is equivalent to the amount of substance fraction xi,prep and the error of reference value δxi,ref is equivalent to δxi,prep + δδxi,ver. Since it is certain that the aggregated error terms are not correlated, those give the standard uncertainty of a reference value which is expressed as u i,ref = u i,prep + u i,ver (11) Measurement Methods A summary of measurement details of participants is listed in Table 4, which includes cylinder number, calibration standard, instrument calibration method and measurement technique. In case of partial participation, participating components are listed. Other details are described in the result reports from participants which are attached in annex B. Table 4. Summary of the measurement methods of the participating laboratories Cylinder Calibration standards Instrument calibration Measurement technique Partial participation D08137 Own standard single point GC-TCD All D9955 Own standard single point GC-TCD All D Own standard Bracketing GC-TCD Ar, Ne, Kr D Own standard Single point GC-TCD Ar 6

9 Degrees of equivalence A unilateral degree of equivalence in key comparison is defined as x i = D i = x i x KCRV (1) and the uncertainty of the difference D i at 95% level of confidence. Here x KCRV denotes the key comparison reference value, and x i the result of laboratory i. Since reference value has its own value as x i,ref, Equation (1) can be expressed as D i = x i x i,ref (13) Based on the valid assumption that the aggregated error terms are not correlated, the standard uncertainty of D i can be expressed as u (D i ) = u i,lab + u i,prep + u i,ver (14) As discussed, the combined standard uncertainty of the reference value comprise that from preparation and that from verification for the mixture involved. 7

10 Measurement s The measurement results in this comparison are summarized in Table 5, 6 and 7. Table 53. Reference values (xref) associated with preparation (uprep) and verification (uver) uncertainties of cylinder i. Amount-of- substance fractions are given in %. Uncertainties are denoted with % relative (k=1). Cyl. Ne Ar Kr Xe xi,ref ui,prep ui,ver xi,ref ui,prep ui,ver xi,ref ui,prep ui,ver xi,ref ui,prep ui,ver D D D D Table 6. Reported values from participating laboratories (xlab) associated with uncertainties (ulab) of cylinder i. Amount-of- substance fractions are given in %. Uncertainties are denoted at (k=). In case of partial participation, only reported results are shown. Cyl. Lab Ne Ar Kr Xe xi,lab ui,lab xi,lab ui,lab xi,lab ui,lab xi,lab ui,lab D08137 KRISS D9955 NIM D NIST D VNIIM

11 Table 7. Degrees of equivalence with uncertainties (k=). In case of partial participation, only reported result are shown. Amount-of- substance fractions are given in %. Cyl. Lab Ne Ar Kr Xe Di u(di) Di u(di) Di u(di) Di u(di) D08137 KRISS D9955 NIM D NIST D VNIIM In figure 1, the degrees of equivalence for each component are aggregated. In case of partial participation, only reported results are given relative to the reference value of which uncertainties are given at 95 % level of confidence. The uncertainties given are the standard uncertainty of difference (Di) between the laboratory result and the reference value. All results of D bias positively from the KCRV. 9

12 Figure 1. Degree of equivalence of each component. In case of partial participation, only reported results are shown. 10

13 Conclusion The results of all the participants in this key comparison are consistent with their KCRVs. All NMI s results agree very well within 0.05% except the NIST. The NIST has determined that their values were biased due to uncorrected matrix effect in sample loading processes and shown that these are now clearly solved in order for their values to be equivalent within KCRVs of CCQM-K113. References 1. International Organization for Standardization, ISO 614:001(E), Gas analysis Preparation of calibration gas mixtures Gravimetric method, Second edition. International organization for standardization, ISO 6143:001(E), Gas analysis - Comparison methods for determining and checking the composition of calibration gas mixtures, Second edition 3. Van der Veen A.M.H. and M. G. Cox, Degrees of equivalence across key comparisons in gas analysis Metrologia 40 (003),

14 Annex A: Measurement reports CCQM-K113 Measurement report: Noble gas mixture Laboratory: KRISS Cylinder number: D08137 Measurements and result Measurement #1 Std. dev. Number of (dd/mm/yy) (%mol/mol) (%, relative) replicates Ne 4/06/ Ar 4/06/ Kr 4/06/ Xe 4/06/ Measurement # Std. dev. Number of (%mol/mol) (%, relative) replicates Ne 3/07/ Ar 3/07/ Kr 3/07/ Xe 3/07/ Measurement #3 Std. dev. Number of (%mol/mol) (%, relative) replicates Ne 03/09/ Ar 03/09/ Kr 03/09/ Xe 03/09/ s (cyl.no. D08137) (%mol/mol) Coverage Factor* Assigned expanded uncertainty (%) Ne Ar Kr Xe * The coverage factor shall be based on approximately 95% confidence. 1

15 Method description Analytical Method: A gas chromatography with thermal conductivity detector (Agilent 6890) was used to assign mole fractions of Ne, Ar, Kr and Xe in He. Detailed analytical condition for this simultaneous measurement is listed in Table 1. High purified He (>99.999%) was fed to the instrument as reference gas for thermal conductivity comparison and carrier gas. Configuration of analytical system used in this key comparison is as follows Gas cylinder regulator MFC sample injection valve column detector integrator (Chemstation) area comparison results Table 4. Analytical condition of instrument used to measure noble gas mixtures of Ne, Ar, Kr and Xe in He Analytical Condition Detector TCD Detector temperature 50 Column Loop size Reference Flow Sample Flow Carrier gas, pressure Oven temperature Packed column, 1/8 MS-5A, 4 ft 0.5 ml He, 40 ml/min 100 ml/min He, 50 psi 65, 7min, 30 /min 4.5 min (ramping) 00, 5 min Calibration Standards: The calibration standards for CCQM-K113 were prepared by gravimetric method in accordance with ISO614:001- preparation method. All impurities in each individual source gas were analyzed by using various detector such as TCD, PDD (Pulsed Discharge ionization Detector), AED (Atomic Emission Detector), FID (Flame Ionization detector) with methanizer and dedicated analyzer such as dew point meter. Purity tables of source gases are shown as below. Table 5. Purity table of He raw gas (#3065) component analyzer distrubution mole fraction (μmol/mol) standard unc. (μmol/mol) H PDD normal

16 O Ar LN cooled oven/tcd LN cooled oven/tcd normal rectangular N PDD rectangular CO Methanizer/FID rectangular CH 4 FID rectangular CO Methanizer/FID rectangular THC FID rectangular H O Dew point normal Ne Gas mass spec. rectangular Kr Gas mass spec. rectangular Xe Gas mass spec. rectangular He 999, (@ k=) Table 3. Purity table of Ar raw gas (#0593) component analyzer distrubution mole fraction (μmol/mol) standard unc. (μmol/mol) H AED normal He Gas mass spec. normal O O analyzer rectangular N TCD rectangular CO Methanizer/FID rectangular CO FID normal CH 4 Methanizer/FID rectangular THC FID rectangular H O Dew point normal Kr TCD rectangular Ne TCD rectangular Xe TCD rectangular Ar 999, (@ k=) Table 4. Purity table of Ne raw gas (#07587) component analyzer distrubution mole fraction (μmol/mol) standard unc. (μmol/mol) 3

17 H AED (Ne carrier) rectangular Ar Gas mass spec. normal O O analyzer rectangular N TCD rectangular CO Methanizer/FID rectangular CO FID normal CH 4 Methanizer/FID rectangular THC FID rectangular H O Dew point normal Kr TCD rectangular Xe TCD rectangular He Gas mass spec. rectangular Ne 999, (@ k=) Table 5. Purity table of Kr raw gas (#GMT9717) component analyzer distrubution mole fraction (μmol/mol) standard unc. (μmol/mol) H PDD normal He Gas mass spec. rectangular Ar O LN cooled oven/tcd LN cooled oven/tcd rectangular rectangular N TCD rectangular CO Methanizer/FID rectangular CO Methanizer/FID normal CH 4 FID rectangular THC FID rectangular H O Dew point rectangular Ne TCD rectangular Xe TCD rectangular Kr 999, (@ k=) 4

18 Table 6. Purity table of Xe raw gas (#XeBV74489) component analyzer distrubution mole fraction (μmol/mol) standard unc. (μmol/mol) H PDD rectangular He Gas mass spec. rectangular Ar O LN cooled oven/tcd LN cooled oven/tcd normal rectangular N TCD normal CO Methanizer/FID rectangular CO Methanizer/FID rectangular CH 4 FID rectangular THC FID rectangular H O Dew point rectangular Kr Gas mass spec. rectangular Ne Gas mass spec. rectangular Xe 999, (@ k=) Purity-assessed raw gases are added to vacuum-cleaned aluminum cylinders (Luxfer, UK) in the order of Xe, Kr, Ne, Ar and He to yield calibration standards in nominal mole fractions of 1,, 10 and 0 % mol mol -1, respectively. An automatic weighing system of which weighing precision is 1 mg was used for the gravimetric addition of raw gases. A tare cylinder of which volume and gross weight are very similar to target cylinders was measured in order of T-A-T-B-T-C-T. This unit sequence was repeated by at least 3 times. In order to estimate substances of amount of each component, molecular weights are theoretical values of relative isotopic abundances from IUPAC. Verification measurements for each component were performed within a relative standard uncertainty less than 0.05 %. Table 7 shows details of the calibration standards used in this key comparison. Table 7. Characteristics of the gravimetric standards (#D08106) used in this key comparison. Mole fraction standard uncertainty component (% mol mol -1 [k=1] ) (% relative) Xe Kr Ne Ar He Balance 5

19 Instrument calibration Single point calibration was applied in order to assign the amount of each component. Measurement sequence was in the order of A-B-A-B-A-(etc.) where A stands for the calibration standard and B stands for KC cylinder (D08137). During whole measurements, analyzer drift was monitored and corrected based on the assumption that the detector response drifts linearly through a unit cycle of A-B-A. Sample handling The sample cylinders were stood for more than one week at room temperature to be equilibrated. Evaluation of measurement uncertainty Table 8. Uncertainty budget of relative standard uncertainties of each component for the measurement of KC cylinder. Unit is % relative. Quantity Ne Ar Kr Xe Standard (#D08106) Analysis (#D08137) Repeatability Reproducibility Total* [k=] * The coverage factor shall be based on approximately 95% confidence. 6

20 International Key Comparison(CCQM-K113) Report Noble Gas Mixture Lab Information Lab Name: National Institute of Metrology (NIM), China Contact point: Dr. HAN Qiao, Dr. HU Shuguo and Dr. Zhang Tiqiang Tel.: Fax.: of Receiving the Comparison Cylinder: November, 014 Cylinder No.: D9955 Measurement and Measurement #1 Measurement # (dd/mm/yy) (mol/mol) Standard deviation (% relative) Ne 9.905% 0.0% Ar 0.15% 0.0% 05/01/15 Kr.0195% 0.0% Xe % 0.05% (dd/mm/yy) (mol/mol) Standard deviation (% relative) Ne 9.90% 0.03% Ar 0.18% 0.03% 06/01/15 Kr.0193% 0.04% Xe % 0.05% Measurement #3 (dd/mm/yy) (mol/mol) Standard deviation (% relative) Ne % 0.03% Ar 0.13% 0.03% 07/01/15 Kr.0193% 0.04% Xe % 0.04% Number of replicates 4 Number of replicates 6 Number of replicates 6 Measurement #4 Standard deviation Number of (dd/mm/yy) (mol/mol) (% relative) replicates Ne 08/01/ % 0.03% 3 1

21 Ar 0.13% 0.04% Kr.0187% 0.03% Xe % 0.06% Measurement #5 (dd/mm/yy) (mol/mol) Standard deviation (% relative) Ne 9.911% 0.0% Ar 0.14% 0.03% 09/01/15 Kr.019% 0.03% Xe % 0.01% Measurement #6 (dd/mm/yy) (mol/mol) Standard deviation (% relative) Ne 9.907% 0.0% Ar 0.10% 0.01% 1/01/15 Kr.0196% 0.05% Xe % 0.01% s Expanded Uncertainty (mol/mol) (% relative) Ne 9.904% 0.15% Ar 0.14% 0.15% Kr.0193% 0.15% Xe 1.010% 0.0% ** The coverage factor k=(95% confidence level) Number of replicates Number of replicates Coverage factor ** Method Description 1. Reference Method Ne, Ar, Kr and Xe were analyzed by GC-TCD (Agilent7890, Agilent, American) with a column of molesieve 5A 60/80(8ft*1/8inch*.0mm). GC conditions Oven temp: 130ºC isotherm 9min Sample loop: 0.mL Valve #1 load time: 0.min Carrier gas: He Carrier flow: 50 psi Sample Flow: 100mL/min. Calibration standard Cylinder No.: D00796

22 Preparation method All of the references we used were made by the gravimetric method according to ISO 614 by ourselves. The parent gases were filled into a 10-liter aluminum cylinder. The cylinder was weighed before and after the filling using a balance with the sensitivity of 1 mg. The weighing data is shown in the table. The uncertainty of reference gas included the contributions from gravimetric method. Mass of parent gas filled, molecular weight and mole fraction of compound were the main sources of the uncertainty of gravimetric method. Weighing data of calibration standard Mass of component added (g) Standard uncertainty (g) Ne Ar Kr Xe He Purity analysis Ne, Ar, Kr, Xe and He were analyzed by GC-PDHID(Pulsed discharged helium ionization detector, Agilent 7890, American) with two columns of molesieve 5A (30m*0.53mm*15μm and 50m*0.53mm*15μm). Uncertainty of calibration standard 3. Instrument calibration Mole fraction (μmol/mol) Expand Uncertainty(k=) (μmol/mol) Ne Ar Kr Xe When Ne, Ar, Kr and Xe were analyzed, A-B-A-B-A type calibration was used. That means the sample gas and our reference gas were measured in the order of Reference Sample Reference Sample Reference. The gas pressure at the sample loop of GC was controlled at almost same value during one analysis sequence. Single point calibration was used to calculate the concentration of target compound in sample cylinder. 4. Sampling handling When package box including comparison cylinder arrived at the lab, it was in good state. Then the box was unpacked and the comparison cylinder was stored at room temperature. A SS regulator was connected to the cylinder. During the analysis, the gas mixtures in both comparison cylinder and the reference cylinder, via regulators, 1/8 inch stainless steel tube, were introduced into a 6-port valve. The pressure gauge and the mass flow meter were connected to the inlet of the 6-port valve to show the pressure and flow rate. The 6-port valve was driven by Nitrogen. The gas pressure before the sample loop was controlled at 0.1 MPa by regulator. Evaluation of measurement uncertainty The contributions of measurement uncertainty were from reference gas, signal readings of the sample gas and reference gas, reproducibility in different days or groups. u( cccqm ) u ( cprm ) u ( ACCQM ) u ( APRM ) u ( fint Here, u means relative standard uncertainty. u ( c CCQM ) : Measurement uncertainty of concentration of the target component in the comparison sample gas er ) 3

23 cylinder. 1. u A ) : Uncertainty of signal reading of the sample gas from peak area on GC. ( CCQM. u A ) : Uncertainty of signal reading of the reference gas from peak area on GC. For the ( PRM A CCQM and A PRM, the relative standard uncertainty could be calculated from the relative standard deviation (RSD) of the signal reading. The relative standard uncertainty is RSD/sqrt(n), where n is the number of signal reading. 3. u c ) : Uncertainty of concentration of the reference gas, which was combined by the uncertainty ( PRM from gravimetric method according to ISO 614 and the uncertainty from the stability of the reference gas. 4. u f ) : Uncertainty of reproducibility in different days or groups. The relative standard uncertainty f int er ( inter was calculated from the relative standard deviation (RSD) of repeating test in different days or groups. The relative standard uncertainty is RSD/sqrt(n), where n is the number of the repeating test. Relative standard uncertainty Ne Ar Kr Xe u ( c PRM ) 0.008% 0.005% 0.010% 0.01% u ( A CCQM ) 0.04% 0.04% 0.04% 0.06% u ( A PRM ) 0.04% 0.04% 0.04% 0.06% u ( f inter ) 0.05% 0.05% 0.05% 0.05% u ( c CCQM ) 0.075% 0.075% 0.075% 0.100% Relative expanded 0.15% 0.15% 0.15% 0.0% uncertainty** **The coverage factor k=(95% confidence level) 4

24 CCQM-K113 Comparison Measurement report: Noble Gases in Helium Laboratory: NIST Cylinder number: D Table 1: Measurement No. 1 (dd/mm/yy) (% mol/mol) Stand. deviation (% mol/mol) Number of replicates Argon 14/01/ Neon 04/0/ Krypton 3/01/ Xenon N/A N/A N/A N/A Table : Measurement No. (dd/mm/yy) (% mol/mol) Stand. deviation (% mol/mol) Number of replicates Argon 15/01/ Neon 05/0/ Krypton 8/01/ Xenon N/A N/A N/A N/A Measurement No. 3* (dd/mm/yy) (% mol/mol) Stand. deviation (% mol/mol) Number of replicates Argon 16/01/ Neon 06/0/ Krypton 9/01/ Xenon N/A N/A N/A N/A Table 3: *If more than three measurements are taken, please copy table and insert at the appropriate place 1

25 Table 4: Summary s: Cylinder # D Gas component Assigned Value (% mol/mol) Coverage factor Assigned expanded Uncertainty (% mol/mol) Argon 0.8 ± 0.08 Neon ± 0.0 Krypton.0639 ± 0.00 Xenon N/A N/A N/A Reference Method: The noble gases were analyzed using an Agilent 6890 gas chromatograph with a thermal conductivity detector (GC/TCD), (NIST# 63009). The components of the gas mixture were separated using a 4.57m X 3.18mm stainless steel packed column containing 80/100 Molecular Sieve 5A. 30mL/min of Research grade ( %) helium was utilized as the carrier gas. Separation of the neon, argon and krypton was achieved with a column temperature of 50 C. The column temperature was then ramped up to 00 C to elute the xenon component before the next sample injection. The TCD detector temperature was 50 C. The sample loop size was 5mL. A computer-operated gas sampling system (COGAS #1) was used to switch from the CCQM cylinder to the respective control cylinder. Each component of the CCQM cylinder was measured against the respective control cylinder during three different analytical periods. Calibration Standards: A. Argon Calibration Standards: Six NIST gravimetrically prepared Primary Standard Materials (PSMs) containing ( ) % mol/mol Ar in helium were used in this analysis. The PSMs are listed below: Cylinder Number Concentration (% k= CAL976 ( ± ) CAL4306 (18.81 ± ) FF16446 ( ± ) FF18081 ( ± ) CAL7141 ( ± ) FF19031 (Control) ( ± ) B. Neon Calibration Standards: Six NIST gravimetrically prepared PSMs containing ( ) % mol/mol Ne in helium were used in this analysis. The PSMs are listed below: Cylinder Number Concentration (% k= CAL0184 ( ± ) CAL7509 ( ± ) FA0431 ( ± )

26 FF19048 ( ± ) FA0480 ( ± ) CAL1038 (Control) ( ± ) C. Krypton Calibration Standards: Six NIST gravimetrically prepared PSMs containing (1.8-.) % mol/mol Kr in helium were used in this analysis. The PSMs are listed below: Cylinder Number Concentration (% k= FF16418 ( ± ) FF18067 ( ± ) FF18011 ( ± ) FA0504 ( ± ) FF1698 (.4080 ± ) FF18000 (Control) ( ± ) The starting materials for these PSMs was Research grade ( ) argon, neon and krypton. The helium balance gas was % pure. The table below gives an assay of the helium used to prepare these standards. Concentration std u Species (µmol/mol) (µmol/mol) He Kr Ar Ne O Instrument Calibration: The Agilent 6890 gas chromatograph was calibrated for each noble gas component using the five gravimetrically prepared PSMs and the control cylinder. The analytical scheme used for each primary standard on each analytical day was: Control cylinder PSM Standard #1 (1st measurement) Control cylinder PSM Standard #1 (nd measurement) Control cylinder PSM Standard #1 (3rd measurement) Control cylinder PSM Standard #1 (4th measurement) Control cylinder PSM Standard #1 (5th measurement) Control cylinder Separately, two Primary Standards could be compared with the control cylinder in one analytical day. Three days were required to compare all five PSMs to the control cylinder. The CCQM sample was then compared to the Control cylinder over three analytical days six measurements of the CCQM sample on each day for a total of 18 measurements. 3

27 Peak Area of the PSM or CCQM sample = Measurement ratio # 1 Peak Area of the Control cylinder A calibration curve for each noble gas component was constructed using the peak area measurement ratios vs. the gravimetric value-assignment of the PSMs. Sample Handling: These analyses are to quantify the Ne, Ar and Kr in a single CCQM-K113 cylinder (D014941). The sample cylinder was fitted with a non-cga valve. KRISS provided an adaptor that terminated in ¼ SS tubing. A low dead-volume, stainless steel regulator was adapted to accept ¼ tubing on its inlet. Sample selection was achieved using a computer operated gas analysis system (COGAS #1). The output pressure of each regulator along with a needle valve was adjusted to provide approximately 50 ml/min sample flow to the instrument. The sample loop was purged for 1 minute prior to injection. Mass fraction calculation: Amount-of-substance = AVERAGE(Trial #1,Trial #,Trial #3) for each noble gas Uncertainty: The amount-of-substance fractions (concentration) for neon, argon and krypton in the K-113 sample cylinder are summarized in table 4. All measured data and calculations for this CCQM Key concentration have been reviewed for sources of systematic and random errors. The uncertainty of the concentration is expressed as an expanded uncertainty, U = kuc with a coverage factor k equal to. The true concentration is asserted to lie within the interval defined with a level of confidence of approximately 95%. Uncertainty calculation: Uexp = Student's t value for (n-1) measurements SQRT(SUMSQ(u1,u,u3)/n measurements) where n is the number of trials and u1, u and u3 are the standard uncertainties of trials 1, and 3, respectively, for each noble gas. Uncertainty s for Analysis of Noble Gases in CCQM-K113: Uncertainty source X I Assumed distribution Standard Uncertainty (%) Relative), u(xi) Gravimetric Standard or Analytical GenLine Curve Fit Gaussian Argon: ± Neon: ± Krypton: ± Gravimetric and Analytical (combined) Authorship: Michael E. Kelley, George C. Rhoderick 4

28 MEASUREMENT REPORT CCQM-K113 «Noble gas mixture» Report Form of CCQM-K113 (Noble gas mixture) Laboratory name: D.I.Mendeleyev Institute for Metrology (VNIIM) Cylinder number: D Measurement #1 (dd/mm/yy) (%mol/mol) Standard deviation (% relative) 1 Ar 0/11/014 0,1635 0,1 3 Ne Kr Xe Measurement # (dd/mm/yy) (%mol/mol) Standard deviation (% relative) Ar 5/11/014 0,1605 0,09 3 Ne Kr Xe Measurement #3 (dd/mm/yy) (%mol/mol) Standard deviation (% relative) Ar 7/11/014 0,1715 0,05 3 Ne Kr Xe s Number of replicates Number of replicates Number of replicates dd/mm/yy (%mol/mol) Expanded uncertainty (%mol/mol) Coverage factor Ar 7/11/014 0,165 0,030 1 The coverage factor shall be based on approximately 95% confidence If more than three measurements are taken, please copy and insert a table of the appropriate format as necessary 1

29 Calibration standards Primary Standard Gas Mixtures, prepared by the gravimetric method from pure substances, according to ISO 614:001 Gas analysis - Preparation of calibration gas mixtures - Gravimetric method were used as calibration standards. Characteristics of pure substances used for preparation of the calibration standards are shown in the tables 1 and. Table 1 Purity table for Argon (cylinder 1080) Mole fraction (µmol/mol) Standard uncertainty (µmol/mol) Ar ,105 0,015 CH 4 0,015 0,009 CO 0,01 0,006 CO 0,104 0,0009 H 0,01 0,006 N 0,066 0,005 O 0,69 0,007 Table Purity table for Helium (cylinder ) Mole fraction (µmol/mol) Standard uncertainty (µmol/mol) He ,89 0,04 Ar 0,0015 0,0009 CH4 0,0005 0,0003 CO 0,001 0,0006 CO 0,013 0,0008 H 0,0005 0,0003 N 0,0079 0,0004 Ne 0,075 0,043 O 0,0077 0,0005 There were prepared 3 calibration gas mixtures on the level of 0 % mol/mol of Argon in Helium from the pure substances. The exact values of Argon amount of substance fraction in the calibration gas mixtures and their standard uncertainties are shown in the table 3. Table 3 Cylinder Mole fraction Standard uncertainty due to weighing number (% mol/mol) and purity (% mol/mol) D1580 Ar 0,73 0,004 D Ar 0,06 0,00 D15800 Ar 0,344 0,005 All standard gas mixtures were prepared in aluminum cylinders (Luxfer), V=5 dm 3. Verification measurements were performed two times, standard deviation for each measurement

30 series was not more than 0,013 % relative. Analytical method All the measurements were carried out by the gas chromatography method with TCD. Instrument: Gas Chromatograph Agilent 6890N Column: MS5A, 10 ft Carrier gas: helium 0 cm 3 /min Oven conditions: 70 ºC Sample loop: 0 µl Data collection: ChemStation for GC Vers. A.10.0 Calibration method and value assignment Single point calibration method was used to determine Argon mole fraction in the investigated gas mixture. Three independent measurement series were carried out under repeatability conditions. Each measurement consisted of 6 sub-measurements. Uncertainty evaluation Uncertainty table: Quantity Xi Estimate xi, % mol/mol Distribution Standard uncertainty u(xi) % mol/mol Sensitivity coefficient ci Contribution ui(y), % mol/mol Calibration standards (weighing + purity+verification) within and between 0,06 Normal 0,0034 0,988 0,0034 0,165 Normal 0, ,014 day measurements Combined standard uncertainty: 0,0144 % mol/mol Coverage factor: k= Expanded uncertainty: 0,030 % mol/mol Relative expanded uncertainty: 0,15 % relative Authorship L.A. Konopelko, A.V. Kolobova, I.I. Vasserman, S.V. Zavyalov, E.V. Gromova, O.V. Efremova 3