Preparation Primary Gas Reference Material (PGRM) by using NIMT Facilities By Ms.Ratirat Sinweeruthai June 9-11, 2010 Tsukuba, Japan 8 th APMP/TCQM Gas CRM Workshop
Overview Objective of Study EMU of Weighing Verification of PGRM Development of NIMT Facilities
Objective NIMT would like to establish the measurement unit in field of amount of substance in parameter of O 2 in N 2 find the method for preparation PGRM develop a system of preparation to be in line with a target uncertainty of NIMT
( ) ( ) ( ) ( )...... 2 2 1 1 2 2 1 2 1 2 2 + + + = = = = = ia p A n i ia i A p A A i i n i i i i x u x x m u m x M u M x x u Uncertainty of PGRM Where u(m i ) : Uncertainty in the Molar Mass u(m A ) : Uncertainty on the Weighings u(x ia ) : Uncertainty in the Purity Analysis (1)
Uncertainty on the weighing ( ) ( ) ( ) ( )....... 3 2 2 3 2 2 2 2 1 2 2 1 2 2 1 + + + = = m u m x m u m x m u m x m u m x i i i A p A A i Where u(m 1 ) : Uncertainty on the First Weighings u(m 2 ) : Uncertainty on the Second Weighings u(m 3 ) : Uncertainty on the Third Weighings i : Component (2)
Weighing Method Ref.: A.Alink (VSL), et al, Metrologia 37, 2000 The equation of weighing a reference cylinder m c + ρ e. p Vc. ρ air = mr + W VR. ρair W. ρ air s (3) The equation of weighing a sample cylinder m c + e. q V c ρ air = m s + M V s ρ air M ρ ρ air s (4)
w j The basic equation of the difference between sample and reference cylinder. ρair, j = e j ( q j p j ) + ( W j M j )(1 ) + ρair, j ( Vs, ρ Where m c m R m s W M e p q V c V R V s ρ air ρ s mass of comparator mass of reference cylinder mass of sample cylinder total mass of mass pieces added to reference cylinder total mass of mass pieces added to sample cylinder calibration factor reading reference cylinder reading sample cylinder volume of contra mass volume of reference cylinder volume of sample cylinder density of air density of mass pieces s j V Ref.: A.Alink (VSL), et al, Metrologia 37, 2000 R (5) )
Weighing process within a weighing cycle. Weighing No. Weighing Step 0 R+W+Q 1 R+W 2 S+M 3 R+W 4 S+M 5 R+W 6 S+M 7 R+W 8 R+W+Q Q is calibration mass pieces Ref.: A.Alink (VSL), et al, Metrologia 37, 2000
Weighing No. Weighing Step Reading 0 R+W+Q m C,0 1 R+W m C,1 2 S+M m C,2 e j = ( m m + m m ) C,0 2m C,1 Q C,8 C,7 3 R+W m C,3 4 S+M m C,4 3 1 ϕ = 2 m 6 i= 1 C, 2i ( mc,1 + mc,7) 2( mc,3 + mc,5) 5 R+W m C,5 6 S+M m C,6 7 R+W m C,7 8 R+W+Q m C,8 Ref.: A.Alink (VSL), et al, Metrologia 37, 2000
Sources of Uncertainty on the weighing Balance (Weighing) A. Alink et.al., Uncertainty calculations for the preparation of primary gas mixture, Metrologia, 2000 Matsumoto et, al., Development of mass measurement equipment using an electronic mass-comparator for gravimetric preparation of reference gas mixtures, Metrologia, 2004 ISO 6142 Weights Standard Weights E2 are traceable to NIMT Buoyancy effect Based on ISO 6142 Measuring Instruments are traceable to NIMT Expansion of the cylinder Based on ISO 6142 Residual gas Based on ISO 6142
Uncertainty of Balance Balance Resolution Drift Incorrect zero point Effect of location of the cylinder on pan Etc. The pool estimate of standard uncertainty is a method to be selected for estimation uncertainty of a balance.
Pooled Estimate of Standard Deviation (S p ) Measurement ABBA Measurement QABABABAQ No. Δm (g) SD (mg) No. Δm (g) SD (mg) 1-21.401 1.528 2-21.398 2.082 3-21.398 0.577 4-21.396 0 5-21.397 1.528 6-21.394 0.577 7-21.396 3.055 8-21.396 0.577 9-21.399 2 10-21.399 0.577 Sp 1.54 1 21.402 2.53 2 21.399 2.42 3 21.398 3.88 4 21.393 2.07 5 21.393 2.42 6 21.392 3.45 7 21.395 2.76 8 21.393 2.76 9 21.398 2.19 10 21.397 3.27 Sp 2.83
Uncertainty Budget of Weighing Uncertainty contributions for vacuum Source Value (g) Standard Uncertainty Distribution Sensitivity Uncertainty contribution Standard Weights 32.00001 0.017 mg Normal 1 0.017 mg Balance 0 2.309 mg Normal 1 2.309 mg Calibration factor (e j ) 0.99950 0.706 mg Normal 0.69 0.488 mg Difference of reading balance (ϕ ) 0.69033 2.000 mg Normal 1 2.000 mg Buoyancy effect 0.00474 0.015 mg Normal 1 0.015 mg m x 33.69458 3.093 mg
Uncertainty contributions for first component Source Value (g) Standard Uncertainty Distribution Sensitivity Uncertainty Contribution Standard Weights 376.00008 0.060 mg Normal 1 0.060 mg Balance 0 2.309 mg Normal 1 2.309 mg Calibration factor (e j ) 0.99900 1.411 mg Normal 0.61 0.861 mg Difference of reading balance (ϕ ) 0.61 1.678 mg Normal 1 1.678 mg Buoyancy effect 0.05544 0.173 mg Normal 1 0.173 mg m x 377.66452 2.986 mg
Uncertainty contributions for second component Source Value (g) Standard Uncertainty Distribution Sensitivity Uncertainty Contribution Standard Weights 1281.50040 0.185 mg Normal 1 0.185 mg Balance 0 2.309 mg Normal 1 2.309 mg Calibration factor (e j ) 1.00000 0.006 mg Normal 0.174 0.006 mg Difference of reading balance (ϕ ) 0.174 2.520 mg Normal 1 2.520 mg Buoyancy effect 0.18801 0.590 mg Normal 1 0.590 mg Expansion of cylinder 0.0238 13.741 mg Rectangular 1 13.741 mg Residual gas 0.0057 3.291 mg Rectangular 1 3.291 mg m x 1282.86242 14.550 mg
Verification of PGRM Paramagnetic Oxygen Analyzer GC-TCD Column : Molecular sieve 5 meter Condition Sample flow rate 30 ml/min Oven temperature 30 o C Detector temperature 200 o C Loop volume 1 ml
Measurement of Goodness-of-fit ( Γ ) The coefficient parameters of the linear analytical function were calculated by using B_Least software.(iso6143) Γ = max xˆ i u x i ( x ) i And Γ = max ŷ i u y i ( y ) i The goodness-of-fit must be Γ 2
Paramagnetic Oxygen Analyzer Model: 4100 Range: 0 100% Resolution: 0.001% Repeatability: <0.01% for O 2 content Manufacturer: Servomex
Verification of PGRM by using Paramagnetic Oxygen Analyzer Mole Fraction (mol/mol) Gravimetric Result u(x), k=2 (µmol/mol) Mole Fraction (mol/mol) Analysis Result u(y), k=2 (µmol/mol) % Error Goodness-of-fit 0.14947 5.2 0.149416 192 0.025 0.19895 5.5 0.198902 192 0.025 0.1494 0.24963 7 0.249605 188 0.006 0.19874 5.8 0.19864 148 0.071 1.2048 0.15243 5.2 0.15245 196 0.023 0.2590 Verification them same as analysis technique of APMP-QM.S2 : O 2 /N 2
Verification of PGRM by using Paramagnetic Oxygen Analyzer Mole Fraction (mol/mol) Gravimetric Result u(x), k=2 (µmol/mol) Mole Fraction (mol/mol) Analysis Result u(y), k=2 (µmol/mol) 0.152425 304 0.1524 196 0.023 0.198949 398 0.1989 192 0.025 0.249625 499 0.2496 188 0.006 % Error Goodness-of-fit 0.0164 Compatibility Criterion 0.14944 390 0.14942 96 0.025 0.19864 424 0.19860 148 0.071 The standard uncertainty of gravimetric results is considered at 0.2% relative. The compatibility criterion used is: grav anal ( x ) 2 u( x ) 2 x x + 2 u grav anal
Verification of PGRM by using Paramagnetic Oxygen Analyzer Mole Fraction (mol/mol) Gravimetric Result u(x), k=2 (µmol/mol) Mole Fraction (mol/mol) Analysis Result u(y), k=2 (µmol/mol) 0.14947 5.2 0.1494 192 0.025 0.19895 5.5 0.1989 192 0.025 0.24963 7 0.2496 198 0.006 % Error Goodness-of-fit 0.6785 Compatibility Criterion 0.15255 194 0.15245 96 0.023 0.19864 148 0.19864 148 0.071 The compatibility criterion used is: grav anal ( x ) 2 u( x ) 2 x x + 2 u grav anal
Analysis Technique y q,1 y p,1 y q,2 y p,2 y q,3 y p,3 y q,4 QC cylinder PGRM 1 QC cylinder PGRM 2 QC cylinder PGRM 3 QC cylinder y i = y q, i 2. y + p, i y q, i+ 1 Where y i is the corrected response Ref.: M.J.T Milton, et al, Metrologia 43, 2006
Verification of PGRM by using GC-TCD Mole Fraction (mol/mol) Gravimetric Result u(x), k=2 (µmol/mol) Analysis Result by Area response y i u(y), k=2 Goodness-of-fit 0.14947 5.2 0.7039 0.00667 0.19895 5.5 0.9306 0.00622 0.7613 0.24963 7 1.176 0.00164 Mole Fraction (mol/mol) Gravimetric Result u(x), k=2 (µmol/mol) Analysis Result by Height response y i u(y), k=2 Goodness-of-fit 0.14947 5.2 0.72749 0.00665 0.19895 5.5 0.93786 0.00585 0.0885 0.24963 7 1.15186 0.00156
Problems from Original System Filling System Precision of weighing Ventilation Weighing System The weighing value is rather a fluctuation
Sources of Filling Error Target mole fraction Prepared mole fraction % Error 0.15 0.1489 0.36 0.20 0.1989 0.53 0.20 0.1987 0.63 0.25 0.2496 0.15 air condition system Balance Filling system Experience
Original Filling System
Modified Filling System
Original Weighing System Ref.:Nobuhiro Matsumoto et al, Metrologia 41, 2004
Specification of Balance Model: KA 10-3 Readability: 2 mg Maximum load: 15 kg Repeatability: 6 mg Linearity: ± 0.2 g
Temperature Chart in Single Chamber
Temperature Chart in Single Chamber
Modified Weighing System
Temperature Chart in Double Chamber
Pooled Estimate of Standard Deviation (S p ) Measurement No. QABABABAQ SD (mg) Single Double 1 10.714 2.53 2 5.241 2.42 3 7.992 3.88 4 6.950 2.07 5 9.592 2.42 6 4.848 3.45 7 2.76 8 2.76 9 2.19 10 3.27 Sp 7.852 2.83 Decrease 64 %
Pooled Estimate of Standard Deviation (S p ) Measurement No. ABBA SD (mg) No Single Double 1 30.7 2.5 1.528 2 63.3 3.8 2.082 3 55.8 5.8 0.577 4 19.7 1.5 0 5 76.9 2. 6 1.528 6 69.2 4.3 0.577 7 102.8 1.7 3.055 8 76.9 4.1 0.577 9 69.2 1.3 2 10 0.577 Sp 67 3.41 1.54
First Weighing System Original System SD > 7.5 mg u(x) WB > 17 mg u(x) > 12 ppm Modified System SD < 3 mg u(x) WB < 14 mg u(x) < 7 ppm Reduced uncertainty 70%
Secondary Weighing System
Specification of Mass Comparator Model Readability Maximum load Repeatability Linearity XP26003L 1 mg 26 kg 3 mg 25 mg
Room Temperature Chart in Chamber of Second Weighing System
Acknowledgement National Metrology Institute of Japan (NMIJ) Dutch Metrology Institute (VSL) National Institute of Metrology (Thailand),(NIMT)
Thank you for your attention