[Header]
Format=SMU
ver=3
appl=GUMWB32
MR=0
SUR=0
SUP=0
UIP=1
UCR=0
status=2
FUEB=0
[Title]
Title='Preparation of a calibration standard'
Ref=''
Date='08/29/2007'
Version=''
Author=''
Description=11
Description[0]='This is the example A1 of the EURACHEM /'
Description[1]='CITAC Guide "Quantifying Uncertainty in Analytical Measurement", Second'
Description[2]='Edition.'
Description[3]=''
Description[4]='A'
Description[5]='calibration standard of ca. 1000 mg\cdot\L^-1 is prepared from a'
Description[6]='high purity metalic cadmium.'
Description[7]=''
Description[8]='After cleaning the surface of the high purity metal it is weighed and dissolved'
Description[9]='in nitric acid in a'
Description[10]='volumetric flask.'
PictureCount=1
DCount=1
[Model]
Model=7
Model[0]='{Calculation of the uncertainty of the volume}'
Model[1]=''
Model[2]='V = V_nominal * f_V\minus\calibration * f_V\minus\temperature * f_V\minus\repeatability;'
Model[3]=''
Model[4]='{Calculation of the uncertainty of the calibration standard}'
Model[5]=''
Model[6]='c_Cd = (k_mL * m * P) / V;'
CE=1
CTC=1
[Components]
CompOrder=3
Comp=9
Comp[0]=V
Comp[1]=V_nominal_
Comp[2]=f_V\minus\calibration_
Comp[3]=f_V\minus\temperature_
Comp[4]=f_V\minus\repeatability_
Comp[5]=c_Cd_
Comp[6]=k_mL_
Comp[7]=m
Comp[8]=P
[COMP 0]
Type=Temp
Definition='Volume of the flask'
Unit='mL'
Description=0
Fcov=2
NomUnit=
UncUnit=
CovID=1
UncID=0
Vnom=100
Ustd=0.0664730521840743
Neff=1098
HB=0
HC=0
HR=0
IO=0
PictureCount=1
DCount=1
[COMP 1]
Type=Const
Definition='Nominal volume of the flask'
Unit='mL'
Description=4
Description[0]='The nominal volume is not associated with any uncertainties. The uncertainty of'
Description[1]='the real volume of the flask has three components, calibration, temperature and'
Description[2]='repeatability. These are included in the uncertainty budget as separate'
Description[3]='factors.'
Vnom=100
PictureCount=1
DCount=1
[COMP 2]
Type=TypBTriangl
Definition='Uncertainty contribution to the volume due to uncertainty in calibration of the flask'
Unit=''
Description=11
Description[0]='The manufacturer of the flask quotes the volume of the flask as 100 mL ±0.1 mL,'
Description[1]='measured at a'
Description[2]='temperature of 20°C. No further statement is made about the level of confidence'
Description[3]='or the underlying distribution. An assumption is necessary to work with this'
Description[4]='uncertainty statement. In this case a'
Description[5]='triangular distribution is assumed. Since f_V\minus\calibration is a'
Description[6]='multiplicative factor to the nominal volume, which is only used to introduce'
Description[7]='the calibration uncertainty, it has the value 1. The halfwidth of limits'
Description[8]='corresponds to the relative uncertainty as stated by the manufacturer (i.e. 0.1'
Description[9]='mL /'
Description[10]='100 mL).'
Vnom=1
Hlim=0,001
PictureCount=1
DCount=1
[COMP 3]
Type=TypBRectang
Definition='Uncertainty contribution to the volume due to temperature variation'
Unit=''
Description=15
Description[0]='The flask has been calibrated at 20°C (manufacturer statement). The laboratory'
Description[1]='temperature varies by ±4°C around this value. The uncertainty of the volume due'
Description[2]='to temperature variations can be calculated from the estimate of the possible'
Description[3]='temperature range and the coefficient of the volume expansion. The volume'
Description[4]='expansion of the liquid is considerably larger than that of the flask, so only'
Description[5]='the volume expansion of the liquid is considered. The coefficient of volume'
Description[6]='expansion for water is 2.1\cdot\10^-4^°C^-1^, which is used here also for the'
Description[7]='nitric acid solution. This leads to a'
Description[8]='possible volume variation of ±(100 \cdot\ 4 \cdot\ 2.1\cdot\10^-4^) mL ='
Description[9]='±0.084 mL. A'
Description[10]='rectangular distribution is assumed for the temperature variation Since'
Description[11]='f_V\minus\temperature is a'
Description[12]='multiplicative factor to the nominal volume, which is only used to introduce'
Description[13]='the temperature uncertainty, it has the value 1. The halfwidth of limits'
Description[14]='corresponds to the possible volume variation as calculated above.'
Vnom=1
Hlim=0,00084
PictureCount=1
DCount=1
[COMP 4]
Type=TypASum
Definition='temperaturabhängige Widerstandsänderung des zu kalibrierenden Widerstandes'
Unit=''
Description=10
Description[0]='The uncertainty due to the repeatability of the filings can be estimated from a'
Description[1]='repeatability experiment on a'
Description[2]='typical example of the flask used. The flask was filled and weighed ten times.'
Description[3]='For the 100 mL flask this resulted in a'
Description[4]='standard deviation of 0.02 mL. This is used directly as the standard'
Description[5]='uncertainty. Since f_V\minus\repeatability is a'
Description[6]='multiplicative factor to the nominal volume, which is only used to introduce'
Description[7]='the repeatability uncertainty, it has the value 1'
Description[8]='±'
Description[9]='0.0002.'
Vnom=1
Ustd=0,0002
Neff=9
PictureCount=1
DCount=1
[COMP 5]
Type=Result
Definition='Concentration of the calibration standard'
Unit='mg/L'
Description=0
Fcov=2
NomUnit=
UncUnit=
CovID=0
UncID=0
Vnom=1002.69972
Ustd=0.835199328725876
Neff=340
HB=1
HC=0
HR=1
IO=0
PictureCount=1
DCount=1
[COMP 6]
Type=Const
Definition='Conversion factor 1000 mL = 1 L'
Unit='mL/L'
Description=0
Vnom=1000
PictureCount=0
DCount=0
[COMP 7]
Type=TypBNormal
Definition='Mass of the metal'
Unit='mg'
Description=12
Description[0]='The mass of the cadmium is determined by a'
Description[1]='tared weighing. The literature of the balance''s manufacturer identifies three'
Description[2]='uncertainty sources for the tared weighing: the repeatablility, the readability'
Description[3]='(digital resolution) of the balance scale and the contribution due to the'
Description[4]='uncertainty in the calibration function of the scale. This calibration function'
Description[5]='has two potential sources of uncertainty, identified as the sensitivity of the'
Description[6]='balance and the linearity. The sensitivity can be neglected because the mass by'
Description[7]='difference is done on the same balance over a'
Description[8]='very narrow range. Bouyance correction is not considered here. Using data from'
Description[9]='the calibration certificate of the balance and following the manufacturer''s'
Description[10]='recommendations on uncertainty estimation, the uncertainty associated with the'
Description[11]='mass of the cadmium is estimated as 0.05 mg.'
Vnom=100,28
Uexp=0,05
Fcov=1
PictureCount=1
DCount=1
[COMP 8]
Type=TypBRectang
Definition='Purity of the metal'
Unit=''
Description=11
Description[0]='The purity of the metal is quoted in the suppliers certificate as 99.99 ±0.01%.'
Description[1]='P'
Description[2]='is expressed as mass fraction (g/g), and its value is therefore 0.9999±0.0001.'
Description[3]='There is no additional information about the uncertainty. A'
Description[4]='rectangular distribution is assumed.'
Description[5]=''
Description[6]='If the manufacturers procedure for cleaning the surface is strictly followed,'
Description[7]='there should be no additional uncertainty contribution. There is no information'
Description[8]='available about the completeness of the dissolution. Therefore one has to check'
Description[9]='with a'
Description[10]='repeated preparation experiment that this contribution can be neglected.'
Vnom=0,9999
Hlim=0,0001
PictureCount=1
DCount=1
[Correlations]
Description=0
[CalCorr]
CNT=9
R[0,5]=-0.7980433
R[0,3]=0.7295802
R[0,2]=0.6141561
R[0,4]=0.3008738
R[5,7]=0.5985996
R[5,3]=-0.5822366
R[5,2]=-0.4901231
R[5,4]=-0.2401103
R[5,8]=0.0693208