Potentiometric Determination of Silver in Fixing Baths

Potentiometric Determination of Silver in Fixing Baths

Equipment
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0430.100 Ag Titrode with Ag2S coating; input 1

Reagents
c(Thioacetamide) = 0.025 mol/L in buffer pH = 5

Sample
5 mL of sample
20 mL c(NaOH) = 2 mol/L
20 mL c(EDTA) = 0.1 mol/L
10 mL w(gelatine) = 0.12 (12%)

Remarks
Determination reaction:

S O

CH3C + OH+ + 2 Ag+ ........CH3C + Ag2S (s) + H+

NH2 NH2

Calculations:

Silver=EP1*C01*C02/C00;3;g/l

Silver = Ag content in g/L
C01 = Ag equivalent (5.394 mg/mL titrating agent)
C02 = titer of titrating agent (1.000)
EDTA keeps silver in solution and gelatine prevents the precipitation from massing together.

Ag2S coating of electrode:
Keep Ag Titrode in alkaline solution of thioacetamide during 15 min.

Buffer pH = 5:
Mix potassium biphthalate solution, c = 0.1 mol/L with Na3PO4 solution, c = 0.05 mol/L. Ratio 50:24. Dissolve 0.5 g thymol per liter buffer solution.

Titrating agent:
Dissolve 1.9 g Thioacetamide in 1 L buffer pH = 5 solution.

Gelatine solution:
Dissolve 12 g gelatine in hot water, add 0.5 g thymol, allow to cool and add up to 1 L.

Literature
Metrohm Application Bulletin No. 72: Potentiometric determination of mercury or silver in the presence of halide ions.

Method documentation

'pa
751 GPD Titrino 15215 751.0010
DET U FixBaths
parameters
>titration parameters
meas.pt.density… 4
min.incr. ….10.0 ml
dos.rate max….. ml/min
signal drift ….20 mV/min
equilibr.time ….38 s
start V: ….OFF
pause ….0 s
dos.element:… internal D0
meas.input: ….1
temperature ….25.0 °C
>stop conditions
stop V: ….abs.
stop V ….12 ml
stop U…. OFF mV
stop EP…. 9
filling rate max…. ml/min
>statistics
status:…. OFF
>evaluation
EPC…. 5
EP recognition: greatest
fix EP1 at U…. OFF mV
pK/HNP: ….OFF
>preselections
req.ident:…. OFF
req.smpl size:…. OFF
activate pulse:…. OFF
------------
'fm
751 GPD Titrino 15215 751.0010
DET U FixBaths
>calculations

Silver=EP1*C01*C02/C00;3;g/l

C00= 5.0
C01= 5.394
C02= 1.0000
------------
'fr
751 GPD Titrino 15215 751.0010
U(init) -168 mV DET U FixBaths
smpl size…. 5.0 ml
EP1…. 10.220 ml…. 99 mV
Silver …..11.025 g/l
stop ….V reached
============
'cu

751 GPD Titrino 15215 751.0010
start V 5.000 ml DET U FixBaths
2.0 ml/div dU=100.0 mV/div

Potentiometric Determination of the White Liquor

Potentiometric Determination of the White Liquor

Equipment
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0239.100 combined pH glass electrode; input 1

Reagents
c(HCl) = 1 mol/L; D0

Sample
2.00 mL white liquor
white liquor is a mixture of NaOH, Na2S (pK1=7.04,pK2=11.96), Na2CO3 (pK1=6.37, pK2=10.25)
50 mL dist. Water

Remarks
Pass a stream of nitrogen through the solution during titration.
1st break: OH- + S-- + 2 H+ H2O + HS-
2nd break: CO3-- + H+HCO3-
3rd break: HCO3 + HS- + 2 H+ H2CO3 + H2S

Calculations:

Total=EP3*C01*C02/C00;2;g/l
Active=(EP3-C03*(EP2-EP1))*C01*C02/C00;2;g/l
Effecti.=EP1*C01*C02/C00;2;g/l
NaOH=(EP1-((EP3-EP2)-(EP2-EP1)))*C01*C02/C00;2;g/l
Na2S=((EP3-EP2)-(EP2-EP1))*C03*C02*C04/C00;2;g/l
Na2CO3=(EP2-EP1)*C03*C02*C05/C00;2;g/l

Total = total alkali (NaOH + Na2S + Na2CO3) as g NaOH per liter
Active = active alkali (NaOH + Na2S) as g NaOH per liter
Effecti. = effective alkali (NaOH + ½ Na2S) as g NaOH per liter
NaOH = concentration of NaOH in g/L
Na₂S = concentration of Na2S in g/L
Na₂CO₃ = concentration of Na2CO3 in g/L
C01 = molecular mass of NaOH (40 g/mol)
C02 = concentration of titrating agent (1 mol/L)
C03 = factor (2)
C04 = molecular mass of ½ Na2S (39 g/mol)
C05 = molecular mass of ½ Na2CO3 (53 g/mol)

Answer

Tota l= 7.625 x 40 x 1 / 2.00 = 152.50 g/L
Active = ( 7.625-2(6.081-5.714)) x 40 x 1 / 2.00 = 137.82 g/L
Effecti.= 5.714 x 40 x 1 / 2.00 = 114.28 g/L
NaOH=(5.714-((7.625-6.081)-(6.081-5.714)))x40x1 / 2.00 = 90.74 g/L
Na2S= ((7.625-6.081)-(6.081-5.714)) x 2 x 1 x 39 / 2.00 = 45.91 g/L
Na2CO3= (6.081-5.714) x 2 x 1 x 53 / 2.00 = 19.45 g/L

EP1 = 5.714
EP2 = 6.081
EP3 = 7.625

Literature
SCAN - N2:63 (1963)

Method documentation

'pa
751 GPD Titrino 15215 751.0010
DET pH W-Liquor
parameters
>titration parameters
meas.pt.density…. 4
min.incr. ….10.0 ml
dos.rate max….. ml/min
signal drift ….50 mV/min
equilibr.time ….26 s
start V:…. OFF
pause ….0 s
dos.element:… internal D0
meas.input: …1
temperature …25.0 °C
>stop conditions
stop V: ….abs.
stop V ….9 ml
stop pH ….OFF
stop EP ….9
filling rate max….. ml/min
>statistics
status:…. OFF
>evaluation
EPC ….5
EP recognition:…. all
fix EP1 at pH…. OFF
pK/HNP: ….OFF
>preselections
req.ident: ….OFF
req.smpl size:…. OFF
activate pulse: ….OFF
------------
'fm
751 GPD Titrino 15215 751.0010
DET pH W-Liquor
>calculations
Total=EP3*C01*C02/C00;2;g/l
Active=(EP3-C03*(EP2-EP1))*C01*C02/C00;2;g/l
Effecti.=EP1*C01*C02/C00;2;g/l
NaOH=(EP1-((EP3-EP2)-(EP2-EP1)))*C01*C02/C00;2;g/l
Na2S=((EP3-EP2)-(EP2-EP1))*C03*C02*C04/C00;2;g/l
Na2CO3=(EP2-EP1)*C03*C02*C05/C00;2;g/l

C00= 2.0
C01= 40
C02= 1
C03= 2
C04= 39
C05= 53
------------
'fr
751 GPD Titrino 15215 751.0010
pHc(init) 12.85 DET pH W-Liquor
smpl size…. 2.0 ml
EP1 …..5.714 ml …10.76 mV
EP2 …..6.081 ml….. 8.67 mV
EP3 …..7.625 ml….. 4.09 mV
Total …152.50 g/l
Active ..137.82 g/l
Effecti. …114.28 g/l
NaOH ….90.74 g/l
Na2S …45.91 g/l
Na2CO3 …19.45 g/l
stop V reached
============
'cu
751 GPD Titrino 15215 751.0010
start V 0.000 ml DET pH W-Liquor
1.0 ml/div dpH=2.0/div

Potentiometric Determination of the White Liquor

Potentiometric Determination of the White Liquor

Equipment
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0239.100 combined pH glass electrode; input 1

Reagents
c(HCl) = 1 mol/L; D0

Sample
2.00 mL white liquor
white liquor is a mixture of NaOH, Na2S (pK1=7.04,pK2=11.96), Na2CO3 (pK1=6.37, pK2=10.25)
50 mL dist. Water

Remarks
Pass a stream of nitrogen through the solution during titration.
1st break: OH- + S-- + 2 H+ H2O + HS-
2nd break: CO3-- + H+HCO3-
3rd break: HCO3 + HS- + 2 H+ H2CO3 + H2S

Calculations:

Total=EP3*C01*C02/C00;2;g/l
Active=(EP3-C03*(EP2-EP1))*C01*C02/C00;2;g/l
Effecti.=EP1*C01*C02/C00;2;g/l
NaOH=(EP1-((EP3-EP2)-(EP2-EP1)))*C01*C02/C00;2;g/l
Na2S=((EP3-EP2)-(EP2-EP1))*C03*C02*C04/C00;2;g/l
Na2CO3=(EP2-EP1)*C03*C02*C05/C00;2;g/l

Total = total alkali (NaOH + Na2S + Na2CO3) as g NaOH per liter
Active = active alkali (NaOH + Na2S) as g NaOH per liter
Effecti. = effective alkali (NaOH + ½ Na2S) as g NaOH per liter
NaOH = concentration of NaOH in g/L
Na₂S = concentration of Na2S in g/L
Na₂CO₃ = concentration of Na2CO3 in g/L
C01 = molecular mass of NaOH (40 g/mol)
C02 = concentration of titrating agent (1 mol/L)
C03 = factor (2)
C04 = molecular mass of ½ Na2S (39 g/mol)
C05 = molecular mass of ½ Na2CO3 (53 g/mol)

Answer

Tota l= 7.625 x 40 x 1 / 2.00 = 152.50 g/L
Active = ( 7.625-2(6.081-5.714)) x 40 x 1 / 2.00 = 137.82 g/L
Effecti.= 5.714 x 40 x 1 / 2.00 = 114.28 g/L
NaOH=(5.714-((7.625-6.081)-(6.081-5.714)))x40x1 / 2.00 = 90.74 g/L
Na2S= ((7.625-6.081)-(6.081-5.714)) x 2 x 1 x 39 / 2.00 = 45.91 g/L
Na2CO3= (6.081-5.714) x 2 x 1 x 53 / 2.00 = 19.45 g/L

EP1 = 5.714
EP2 = 6.081
EP3 = 7.625

Literature
SCAN - N2:63 (1963)

Method documentation

'pa
751 GPD Titrino 15215 751.0010
DET pH W-Liquor
parameters
>titration parameters
meas.pt.density…. 4
min.incr. ….10.0 ml
dos.rate max….. ml/min
signal drift ….50 mV/min
equilibr.time ….26 s
start V:…. OFF
pause ….0 s
dos.element:… internal D0
meas.input: …1
temperature …25.0 °C
>stop conditions
stop V: ….abs.
stop V ….9 ml
stop pH ….OFF
stop EP ….9
filling rate max….. ml/min
>statistics
status:…. OFF
>evaluation
EPC ….5
EP recognition:…. all
fix EP1 at pH…. OFF
pK/HNP: ….OFF
>preselections
req.ident: ….OFF
req.smpl size:…. OFF
activate pulse: ….OFF
------------
'fm

751 GPD Titrino 15215 751.0010

DET pH W-Liquor

>calculations

Total=EP3*C01*C02/C00;2;g/l

Active=(EP3-C03*(EP2-EP1))*C01*C02/C00;2;g/l

Effecti.=EP1*C01*C02/C00;2;g/l

NaOH=(EP1-((EP3-EP2)-(EP2-EP1)))*C01*C02/C00;2;g/l

Na2S=((EP3-EP2)-(EP2-EP1))*C03*C02*C04/C00;2;g/l

Na2CO3=(EP2-EP1)*C03*C02*C05/C00;2;g/l

C00= 2.0

C01= 40

C02= 1

C03= 2

C04= 39

C05= 53

------------

'fr

751 GPD Titrino 15215 751.0010

pHc(init) 12.85 DET pH W-Liquor

smpl size…. 2.0 ml

EP1 …..5.714 ml …10.76 mV

EP2 …..6.081 ml….. 8.67 mV

EP3 …..7.625 ml….. 4.09 mV

Total …152.50 g/l

Active ..137.82 g/l

Effecti. …114.28 g/l

NaOH ….90.74 g/l

Na2S …45.91 g/l

Na2CO3 …19.45 g/l

stop V reached

============

'cu

751 GPD Titrino 15215 751.0010

start V 0.000 ml DET pH W-Liquor

1.0 ml/div dpH=2.0/div

Potentiometric Determination of the White Liquor

Potentiometric Determination of the White Liquor

Equipment
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0239.100 combined pH glass electrode; input 1

Reagents
c(HCl) = 1 mol/L; D0

Sample
2.00 mL white liquor
white liquor is a mixture of NaOH, Na2S (pK1=7.04,pK2=11.96), Na2CO3 (pK1=6.37, pK2=10.25)
50 mL dist. Water

Remarks
Pass a stream of nitrogen through the solution during titration.
1st break: OH- + S-- + 2 H+ H2O + HS-
2nd break: CO3-- + H+HCO3-
3rd break: HCO3 + HS- + 2 H+ H2CO3 + H2S

Calculations:

Total=EP3*C01*C02/C00;2;g/l
Active=(EP3-C03*(EP2-EP1))*C01*C02/C00;2;g/l
Effecti.=EP1*C01*C02/C00;2;g/l
NaOH=(EP1-((EP3-EP2)-(EP2-EP1)))*C01*C02/C00;2;g/l
Na2S=((EP3-EP2)-(EP2-EP1))*C03*C02*C04/C00;2;g/l
Na2CO3=(EP2-EP1)*C03*C02*C05/C00;2;g/l

Total = total alkali (NaOH + Na2S + Na2CO3) as g NaOH per liter
Active = active alkali (NaOH + Na2S) as g NaOH per liter
Effecti. = effective alkali (NaOH + ½ Na2S) as g NaOH per liter
NaOH = concentration of NaOH in g/L
Na₂S = concentration of Na2S in g/L
Na₂CO₃ = concentration of Na2CO3 in g/L
C01 = molecular mass of NaOH (40 g/mol)
C02 = concentration of titrating agent (1 mol/L)
C03 = factor (2)
C04 = molecular mass of ½ Na2S (39 g/mol)
C05 = molecular mass of ½ Na2CO3 (53 g/mol)

Answer

Tota l= 7.625 x 40 x 1 / 2.00 = 152.50 g/L
Active = ( 7.625-2(6.081-5.714)) x 40 x 1 / 2.00 = 137.82 g/L
Effecti.= 5.714 x 40 x 1 / 2.00 = 114.28 g/L
NaOH=(5.714-((7.625-6.081)-(6.081-5.714)))x40x1 / 2.00 = 90.74 g/L
Na2S= ((7.625-6.081)-(6.081-5.714)) x 2 x 1 x 39 / 2.00 = 45.91 g/L
Na2CO3= (6.081-5.714) x 2 x 1 x 53 / 2.00 = 19.45 g/L

EP1 = 5.714
EP2 = 6.081

EP3 = 7.625

Literature

SCAN - N2:63 (1963)

Method documentation

'pa

751 GPD Titrino 15215 751.0010

DET pH W-Liquor

parameters

>titration parameters

meas.pt.density…. 4

min.incr. ….10.0 ml

dos.rate max….. ml/min

signal drift ….50 mV/min

equilibr.time ….26 s

start V:…. OFF

pause ….0 s

dos.element:… internal D0

meas.input: …1

temperature …25.0 °C

>stop conditions

stop V: ….abs.

stop V ….9 ml

stop pH ….OFF

stop EP ….9

filling rate max….. ml/min

>statistics

status:…. OFF

>evaluation

EPC ….5

EP recognition:…. all

fix EP1 at pH…. OFF

pK/HNP: ….OFF

>preselections

req.ident: ….OFF

req.smpl size:…. OFF

activate pulse: ….OFF

------------

'fm

751 GPD Titrino 15215 751.0010

DET pH W-Liquor

>calculations

Total=EP3*C01*C02/C00;2;g/l

Active=(EP3-C03*(EP2-EP1))*C01*C02/C00;2;g/l

Effecti.=EP1*C01*C02/C00;2;g/l

NaOH=(EP1-((EP3-EP2)-(EP2-EP1)))*C01*C02/C00;2;g/l

Na2S=((EP3-EP2)-(EP2-EP1))*C03*C02*C04/C00;2;g/l

Na2CO3=(EP2-EP1)*C03*C02*C05/C00;2;g/l

C00= 2.0

C01= 40

C02= 1

C03= 2

C04= 39

C05= 53

------------

'fr

751 GPD Titrino 15215 751.0010

pHc(init) 12.85 DET pH W-Liquor

smpl size…. 2.0 ml

EP1 …..5.714 ml …10.76 mV

EP2 …..6.081 ml….. 8.67 mV

EP3 …..7.625 ml….. 4.09 mV

Total …152.50 g/l

Active ..137.82 g/l

Effecti. …114.28 g/l

NaOH ….90.74 g/l

Na2S …45.91 g/l

Na2CO3 …19.45 g/l

stop V reached

============

'cu

751 GPD Titrino 15215 751.0010

start V 0.000 ml DET pH W-Liquor

1.0 ml/div dpH=2.0/div

Potentiometric Determination of the 2-Aminophenol

Potentiometric Determination of the 2-Aminophenol

Equipment
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0431.100 Pt Titrode; input 1

Reagents
c(NaNO2) = 0.2 mol/L; D0

Sample
app. 0.3 ... 0.35 g sample (2-aminophenol)
10 mL w(HBr) = 0.20 (20%)
30 mL dist. water

Remarks
Determination reaction:

H+R-NH2 + HNO2 + HBr ......[R-NN+]Br- + 2 H2O

Calculations:

Content=EP1*C01*C02*C03/C00;2;%

Content = content of 2-aminophenol in %
C01 = molecular mass of 2-aminophenol (109.13 g/mol)
C02 = factor for conversion mL , and for % (0.001*100=0.1)
C03 = concentration of titrating agent (0.2 mol/L)
Instead of the Pt Titrode a combined Pt electrode 6.0420.100 can be used.

Answer

Content = 14.396 x 109.13 x 0.1 x 0.2 / 0.3188 = 98.56%

EP1 = 14.396
C00 = 0.3188 g

Literature
Metrohm Application Bulletin No. 228: Diazotisation titrations

Method documentation

'pa
751 GPD Titrino 15215 751.0010
MET U Diazo
parameters
>titration parameters
V step… 0.10 ml
dos.rate max…. ml/min
signal drift ….OFF mV/min
equilibr.time ….15 s
start V:…. OFF
pause ….30 s
os.element:…. internal D0
meas.input: …1
temperature ….25.0 °C
>stop conditions
stop V: ….abs.
stop V ….17 ml
stop U …OFF mV
stop EP …9
filling rate max…. ml/min
>statistics
status: …OFF
>evaluation
EPC …30 mV
EP recognition:… all
fix EP1 at U OFF …mV
pK/HNP: …OFF
>preselections
req.ident: …OFF
req.smpl size:… value
activate pulse: ….OFF
------------
'fm
751 GPD Titrino 15215 751.0010
MET U Diazo
>calculations

Content=EP1*C01*C02*C03/C00;2;%

C00= 0.3188
C01= 109.13
C02= 0.1
C03= 0.2
------------
'fr
751 GPD Titrino 15215 751.0010

smpl size 0.3188 g id#1 09120

EP1 14.396 ml -203 mV

Content 98.56 %

stop V reached

============

'cu

751 GPD Titrino 15215 751.0010

start V 10.000 ml MET U Diazo

2.0 ml/div dU=100.0 mV/div

Potentiometric Determination of the 2-Aminophenol

Potentiometric Determination of the 2-Aminophenol

Equipment
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0431.100 Pt Titrode; input 1

Reagents
c(NaNO2) = 0.2 mol/L; D0

Sample
app. 0.3 ... 0.35 g sample (2-aminophenol)
10 mL w(HBr) = 0.20 (20%)
30 mL dist. water

Remarks
Determination reaction:

H+R-NH2 + HNO2 + HBr ......[R-NN+]Br- + 2 H2O

Calculations:

Content=EP1*C01*C02*C03/C00;2;%

Content = content of 2-aminophenol in %
C01 = molecular mass of 2-aminophenol (109.13 g/mol)
C02 = factor for conversion mL , and for % (0.001*100=0.1)
C03 = concentration of titrating agent (0.2 mol/L)
Instead of the Pt Titrode a combined Pt electrode 6.0420.100 can be used.

Answer

Content = 14.396 x 109.13 x 0.1 x 0.2 / 0.3188 = 98.56%

EP1 = 14.396
C00 = 0.3188 g

Literature
Metrohm Application Bulletin No. 228: Diazotisation titrations

Method documentation

'pa
751 GPD Titrino 15215 751.0010
MET U Diazo
parameters
>titration parameters
V step… 0.10 ml
dos.rate max…. ml/min
signal drift ….OFF mV/min
equilibr.time ….15 s
start V:…. OFF
pause ….30 s
os.element:…. internal D0
meas.input: …1
temperature ….25.0 °C
>stop conditions
stop V: ….abs.
stop V ….17 ml
stop U …OFF mV
stop EP …9
filling rate max…. ml/min
>statistics
status: …OFF
>evaluation
EPC …30 mV
EP recognition:… all
fix EP1 at U OFF …mV
pK/HNP: …OFF
>preselections
req.ident: …OFF
req.smpl size:… value
activate pulse: ….OFF
------------
'fm
751 GPD Titrino 15215 751.0010
MET U Diazo
>calculations

Content=EP1*C01*C02*C03/C00;2;%

C00= 0.3188

C01= 109.13

C02= 0.1

C03= 0.2

------------

'fr

751 GPD Titrino 15215 751.0010

U(init) 125 mV MET U Diazo

smpl size 0.3188 g id#1 09120

EP1 14.396 ml -203 mV

Content 98.56 %

stop V reached

============

'cu

751 GPD Titrino 15215 751.0010

start V 10.000 ml MET U Diazo

2.0 ml/div dU=100.0 mV/div

Potentiometric Determination of the 2-Aminophenol

Potentiometric Determination of the 2-Aminophenol

Equipment
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0431.100 Pt Titrode; input 1

Reagents
c(NaNO2) = 0.2 mol/L; D0

Sample
app. 0.3 ... 0.35 g sample (2-aminophenol)
10 mL w(HBr) = 0.20 (20%)
30 mL dist. water

Remarks
Determination reaction:

H+R-NH2 + HNO2 + HBr ......[R-NN+]Br- + 2 H2O

Calculations:

Content=EP1*C01*C02*C03/C00;2;%

Content = content of 2-aminophenol in %
C01 = molecular mass of 2-aminophenol (109.13 g/mol)
C02 = factor for conversion mL , and for % (0.001*100=0.1)
C03 = concentration of titrating agent (0.2 mol/L)
Instead of the Pt Titrode a combined Pt electrode 6.0420.100 can be used.

Answer

Content = 14.396 x 109.13 x 0.1 x 0.2 / 0.3188 = 98.56%

EP1 = 14.396
C00 = 0.3188 g

Literature
Metrohm Application Bulletin No. 228: Diazotisation titrations

Method documentation

'pa
751 GPD Titrino 15215 751.0010
MET U Diazo
parameters
>titration parameters
V step… 0.10 ml
dos.rate max…. ml/min
signal drift ….OFF mV/min
equilibr.time ….15 s
start V:…. OFF
pause ….30 s
os.element:…. internal D0
meas.input: …1
temperature ….25.0 °C
>stop conditions
stop V: ….abs.
stop V ….17 ml
stop U …OFF mV
stop EP …9
filling rate max…. ml/min
>statistics
status: …OFF
>evaluation
EPC …30 mV
EP recognition:… all
fix EP1 at U OFF …mV
pK/HNP: …OFF
>preselections
req.ident: …OFF
req.smpl size:… value
activate pulse: ….OFF
------------
'fm
751 GPD Titrino 15215 751.0010
MET U Diazo
>calculations

Content=EP1*C01*C02*C03/C00;2;%

C00= 0.3188
C01= 109.13
C02= 0.1
C03= 0.2
------------
'fr
751 GPD Titrino 15215 751.0010
smpl size 0.3188 g id#1 09120
EP1 14.396 ml -203 mV
Content 98.56 %
stop V reached
============
'cu

751 GPD Titrino 15215 751.0010
start V 10.000 ml MET U Diazo
2.0 ml/div dU=100.0 mV/div