[Header]
Format=SMU
ver=3
appl=GUMWB32
MR=0
FUEB=0

[Title]
Title='Determination of total hardness of water by complexonometric titration (EDTA)'
Description=36
Description[0]='SCOPE AND FIELD OF APPLICATION: The present method is used for the'
Description[1]='determination of total hardness of water in drinking water, ground water and'
Description[2]='surface water.'
Description[3]=''
Description[4]='PRINCIPLE: The method is based on the reaction of heavy metal ions and alkaline'
Description[5]='earth metal ions (mostly Ca and Mg) with EDTA in basic solution. The sample is'
Description[6]='titrated with EDTA solution of known concentration until the initially obtained'
Description[7]='violet color of the solution has turned to stabile blue color. ET-00 serves as'
Description[8]='an indicator with this measurement.'
Description[9]=''
Description[10]='The values of uncertainty components of volumetric ware are taken according to'
Description[11]='our experience, experiments carried out in our lab and data from manufactures'
Description[12]='of the volumetric ware. The users of these examples are advised to use this'
Description[13]='data only as the first approximation and substitute these uncertainty estimates'
Description[14]='by their own data that corresponds to the actual situation in their own lab.'
Description[15]=''
Description[16]='***Determination of the concentration of the EDTA standard solution***'
Description[17]=''
Description[18]='For the determination of the concentration of previously prepared EDTA solution'
Description[19]='(the titrant), the 0.05 M MgSO_4 standard substance solution was prepared by'
Description[20]='dissolving 0.05 mol MgSO_4*7H_2_O in a 1000 ml volumetric flask. 10 ml of'
Description[21]='MgSO_4 standard substance solution (V_MgSO4) was transferred to a 250 cm³'
Description[22]='titration vessel and 50 cm³ of distilled water, 5 cm³ of ammonia buffer'
Description[23]='solution and a bit of indicator ET-00 were added. The standard substance'
Description[24]='solution was titrated until the initially obtained violet color of the solution'
Description[25]='had turned to stabile blue color. For the determination of the concentration of'
Description[26]='the EDTA standard solution (c_EDTA) 4 titrations were carried out.'
Description[27]=''
Description[28]='***Determination of total hardness of water***'
Description[29]=''
Description[30]='20 cm³ of sample (V_sample) was transferred to a titration vessel and 2 cm³ of'
Description[31]='the ammonia buffer solution and a bit of indicator ET-00 were added. The'
Description[32]='obtained violet solution was titrated with the EDTA standard solution until the'
Description[33]='color of the solution had turned to a stabile blue. all in all 6 titrations'
Description[34]='were carried out for the determination of water hardness.'
Description[35]=''

[Model]
Model=31
Model[0]='{The main equation}'
Model[1]=''
Model[2]='x =( 1000 * V_EDTA\us\sample * c_EDTA  * R ) *2/ V_sample;'
Model[3]=''
Model[4]='{Determination of the concentration of the titrant (EDTA standard solution)}'
Model[5]=''
Model[6]='c_EDTA =  c_MgSO4 * V_MgSO4 * R_EDTA / V_EDTA\us\stand;'
Model[7]=''
Model[8]='{Uncertainty of the volume of MgSO_4 standard substance solution}'
Model[9]=''
Model[10]='V_MgSO4 = V_MgSO4\us\rep +V_MgSO4\us\cal+ V_MgSO4\us\tem;'
Model[11]='V_MgSO4\us\tem = V_MgSO4\us\cal * \Theta\ * \gamma\;'
Model[12]=''
Model[13]='{Uncertainty of the volume of EDTA standard solution in the case of standardization}'
Model[14]=''
Model[15]='V_EDTA\us\stand = V_EDTA\us\rep + V_EDTA\us\tem + V_EDTA\us\end;'
Model[16]='V_EDTA\us\tem = V_EDTA\us\rep * \Theta\ * \gamma\;'
Model[17]=''
Model[18]='R_EDTA = V_EDTA\us\rep / const(V_EDTA\us\rep);'
Model[19]=''
Model[20]='{Uncertainty of the volume of EDTA standard solution needed for the titration of sample solution }'
Model[21]=''
Model[22]='V_EDTA\us\sample = V_EDTA\us\rep\us\sample+ V_EDTA\us\tem\us\sample + V_EDTA\us\end\us\sample;'
Model[23]='V_EDTA\us\tem\us\sample= V_EDTA\us\rep\us\sample * \Theta\ * \gamma\;'
Model[24]=''
Model[25]='R = V_EDTA\us\rep\us\sample /const(V_EDTA\us\rep\us\sample);'
Model[26]=''
Model[27]='{Uncertainty of the volume of sample solution}'
Model[28]=''
Model[29]='V_sample = V_rep\us\sample + V_tem\us\sample + V_cal\us\sample;'
Model[30]='V_tem\us\sample = V_rep\us\sample * \Theta\ * \gamma\;'
CE=1
CTC=1

[Components]
CompOrder=3
Comp=23
Comp[0]=x
Comp[1]=V_EDTA\us\sample_
Comp[2]=c_EDTA_
Comp[3]=R
Comp[4]=V_sample_
Comp[5]=c_MgSO4_
Comp[6]=V_MgSO4_
Comp[7]=R_EDTA_
Comp[8]=V_EDTA\us\stand_
Comp[9]=V_MgSO4\us\rep_
Comp[10]=V_MgSO4\us\cal_
Comp[11]=V_MgSO4\us\tem_
Comp[12]=\Theta\
Comp[13]=\gamma\
Comp[14]=V_EDTA\us\rep_
Comp[15]=V_EDTA\us\tem_
Comp[16]=V_EDTA\us\end_
Comp[17]=V_EDTA\us\rep\us\sample_
Comp[18]=V_EDTA\us\tem\us\sample_
Comp[19]=V_EDTA\us\end\us\sample_
Comp[20]=V_rep\us\sample_
Comp[21]=V_tem\us\sample_
Comp[22]=V_cal\us\sample_

[COMP 0]
Type=Result
Definition='Total hardness of water'
Unit='mg-eqv/l'
Description=0
Fcov=2
NomUnit=
UncUnit=
CovID=0
UncID=0
Vnom=12.701014032572
Ustd=0.135303075623714
Neff=113
HB=1
HC=0
HR=1
IO=0

[COMP 1]
Type=Temp
Definition='Volume of the EDTA standard solution needed for the titration of the sample'
Unit='ml'
Description=0
Fcov=2
NomUnit=
UncUnit=
CovID=0
UncID=0
Vnom=6.2
Ustd=0.0510134729393455
Neff=53
HB=0
HC=0
HR=0
IO=0

[COMP 2]
Type=Temp
Definition='Concentration of the EDTA standard solution'
Unit='mol/l'
Description=0
Fcov=2
NomUnit=
UncUnit=
CovID=0
UncID=0
Vnom=0.0204855065041483
Ustd=9.04633242632244E-5
Neff=72
HB=0
HC=0
HR=0
IO=0

[COMP 3]
Type=Temp
Definition='Recovery factor of the sample analysis'
Unit='unitless'
Description=0
Fcov=2
NomUnit=
UncUnit=
CovID=0
UncID=0
Vnom=1
Ustd=0.0015582125533537
Neff=5
HB=0
HC=0
HR=0
IO=0

[COMP 4]
Type=Temp
Definition='Volume of the pipette used for measuring the sample'
Unit='ml'
Description=0
Fcov=2
NomUnit=
UncUnit=
CovID=0
UncID=0
Vnom=20
Ustd=0.0871779788708135
Neff=70
HB=0
HC=0
HR=0
IO=0

[COMP 5]
Type=TypBNormal
Definition='Concentration of the MgSO_4 standard substance solution'
Unit='mol/l'
Description=0
Vnom=0,05
Uexp=0,00007
Fcov=1

[COMP 6]
Type=Temp
Definition='Volume of the MgSO_4 standard substance solution taken for the titration of the EDTA standard solution'
Unit='ml'
Description=0
Fcov=2
NomUnit=
UncUnit=
CovID=0
UncID=0
Vnom=10
Ustd=0.0403301376144441
Neff=51
HB=0
HC=0
HR=0
IO=0

[COMP 7]
Type=Temp
Definition='Recovery factor of the standardization of the EDTA standard solution'
Unit='unitless'
Description=0
Fcov=2
NomUnit=
UncUnit=
CovID=0
UncID=0
Vnom=1
Ustd=0.000307282597562225
Neff=3
HB=0
HC=0
HR=0
IO=0

[COMP 8]
Type=Temp
Definition='Volume of the EDTA standard solution needed for the titration of MgSO_4 standard substance solution'
Unit='ml'
Description=0
Fcov=2
NomUnit=
UncUnit=
CovID=0
UncID=0
Vnom=24.4075
Ustd=0.0331113993728746
Neff=69
HB=0
HC=0
HR=0
IO=0

[COMP 9]
Type=TypBNormal
Definition='Repeatability uncertainty component of the 10 ml pipette used to measure the 10 ml aliquot of the MgSO_4 standard substance solution'
Unit='ml'
Description=2
Description[0]='Estimate of uncertainty due to repeatability of volume of MgSO_4 primary'
Description[1]='standard solution is taken as 0.4% of the volume of the pipette.'
Vnom=0
Uexp=0,04
Fcov=1

[COMP 10]
Type=TypBRectang
Definition='Value and the calibration uncertainty component of the volume of the 10 ml pipette used to measure the 10 ml aliquot of the MgSO_4 standard substance solution'
Unit='ml'
Description=0
Vnom=10
Hlim=0,003

[COMP 11]
Type=Temp
Definition='Temperature uncertainty component of the volume of the 10 ml pipette used to measure the 10 ml aliquot of the MgSO_4 standard substance solution'
Unit='ml'
Description=0
Fcov=2
NomUnit=
UncUnit=
CovID=0
UncID=0
Vnom=0
Ustd=0.00484974226119286
Neff=10000
HB=0
HC=0
HR=0
IO=0

[COMP 12]
Type=TypBRectang
Definition='Difference of the actual laboratory temperature from 20 degrees centigrade'
Unit='°C'
Description=0
Vnom=0
Hlim=4

[COMP 13]
Type=Const
Definition='The coefficient of volume expansion for water'
Unit='1/°C'
Description=0
Vnom=0.00021

[COMP 14]
Type=TypAExper
Definition='Value and the repeatability unceratinty component of the volume of EDTA standard solution needed for the titration of MgSO_4 primary standard solution (replicate tests)'
Unit='ml'
Description=0
Observations=4
Reading=4
Reading[0]=24,42
Reading[1]=24,39
Reading[2]=24,42
Reading[3]=24,40
Mode=0
MinObs=4

[COMP 15]
Type=Temp
Definition='Temperature uncertainty component of the volume of EDTA standard solution  needed for the titration of MgSO_4 primary standard solution'
Unit='ml'
Description=0
Fcov=2
NomUnit=
UncUnit=
CovID=0
UncID=0
Vnom=0
Ustd=0.0118370084240065
Neff=10000
HB=0
HC=0
HR=0
IO=0

[COMP 16]
Type=TypBNormal
Definition='The end-point detrmination uncertainty component  of the volume of EDTA standard  solution needed for the titration of MgSO_4 primary standard solution'
Unit='ml'
Description=0
Vnom=0
Uexp=0,03
Fcov=1

[COMP 17]
Type=TypAExper
Definition='Value and the repeatability uncertainty component of the volume of the EDTA standard solution needed for the titration of sample (replicate tests)'
Unit='ml'
Description=0
Observations=6
Reading=6
Reading[0]=6,19
Reading[1]=6,17
Reading[2]=6,18
Reading[3]=6,22
Reading[4]=6,23
Reading[5]=6,21
Mode=0
MinObs=6

[COMP 18]
Type=Temp
Definition='Temperature uncertainty component of the volume of EDTA standard solution needed for the titration of sample solution'
Unit='ml'
Description=0
Fcov=2
NomUnit=
UncUnit=
CovID=0
UncID=0
Vnom=0
Ustd=0.00300684020193957
Neff=10000
HB=0
HC=0
HR=0
IO=0

[COMP 19]
Type=TypBNormal
Definition='The end-point determination uncertainty component of the volume of EDTA standard solution needed for the titration of sample solution'
Unit='ml'
Description=2
Vnom=0
Uexp=0,05
Fcov=1
Description[0]='The endpoint detection uncertainty is estimated slightly larger for the sample'
Description[1]='than for the titrant standardisation.'

[COMP 20]
Type=TypBNormal
Definition='Value and the repeatability uncertainty component of the 20 ml pipette with which the sample solution was measured for the analysis'
Unit='ml'
Description=2
Description[0]='Estimate of uncertainty due to repeatability of volume of MgSO_4 primary'
Description[1]='standard solution is taken as 0.4% of the volume of the pipette.'
Vnom=0
Uexp=0,08
Fcov=1

[COMP 21]
Type=Temp
Definition='Temperature uncertainty component of the 20 ml pipette with which the sample solution was measured for the analysis'
Unit='ml'
Description=0
Fcov=2
NomUnit=
UncUnit=
CovID=0
UncID=0
Vnom=0
Ustd=0
Neff=10000
HB=0
HC=0
HR=0
IO=0

[COMP 22]
Type=TypBRectang
Definition='Calibration uncertainty component of the 20 ml pipette with which the sample solution was measured for the analysis'
Unit='ml'
Description=0
Vnom=20
Hlim=0,06

[Correlations]
Description=0