M297
METTLER TOLEDO
Factor Determination of Cerium Sulphate vs. Hydroquinone
Titration Excellence Line: The factor of the cerium sulfate solution will be used for the gold determination of
gold alloys and pure gold. See also applications M298 and M299.
Sample
Hydroquinone, C6H6O2
c (1/2 C6H6O2)= 0.05mol/L: 1.5 mL
Substance
Hydroquinone, C6H6O2
M(C 6H6O2) = 110.11 g/mol, z = 2
Chemicals
Hydrochloric acid 0.1 mol/L, Fluka
Titrant
Cerium sulfate, c(Ce(SO4) 2) = 0.01 mol/L
Standard
----
Instruments
T50/70/90
XS205 Balance
Accessories
Glass beaker, ME-101446
Olivetti JobJet 210 Printer
LabX 2.52
SP250 Pump, ME-51108016
Additional Dosing Unit, ME-51109030
Indication
DM140-SC
Preparation and Procedures
- Place an empty glass titration beaker on the manual titration stand
- 40 mL HCl 0.1 mol/l will be pumped in automatically
- 1.5 mL hydroquinone will be dispensed
- The sample will be titrated with cerium sulfate 0.01 mol/L using a
DM140-SC electrode
- Weigh 2.753 g hydroquinone in a glass beaker, transfer it
with deionized water into a 1 L measuring flask
- Add approx. 900 mL deionized water
- Add 10 mL H2SO4 96%
- Fill up to the mark with deionized water
- Pipette 50.0 mL of cerium sulfate 0.1 mol/L (Merck 1.09092.1000)
in a 500 mL volumetric flask
- Add approx. 400 mL deionized water
- Add 10 mL H2SO4 96% and gentle mix it
- Fill up to the mark with deionized water
Remarks
Theoretical consumption
Chemistry
C6H6O2 + 2Ce 4+ = C 6H4O2 + 2Ce3+ 2H +
- 1 mL hydroquinone, c (1/2 0.05 mol/l) corresponds to a consumption
of 5 mL cerium sulfate, c (0.01 mol/L)
Literature
Calculation
R1 = VENDDi*0.05/(VEQ*c)
C1 = 1
- Application Brochure Gold and Silver DL67/DL70OES/DL77
ME-724613
H[Cerium sulfate] = Mean [R1]
Results
Waste
Waste
disposal
disposal
Hydroquinone: Evaporate solution, special waste
Cerium:
Precipitate with NaOH and filtrate,
special waste
Author
Claudia Schreiner
Results
Start time:
22.03.2007
Sample Data
No. 1/6
No. 2/6
No. 3/6
No. 4/6
No. 5/6
No. 6/6
Note / ID
Hydroquinone
Hydroquinone
Hydroquinone
Hydroquinone
Hydroquinone
Hydroquinone
Sample size
1.5 mL
1.5 mL
1.5 mL
1.5 mL
1.5 mL
1.5 mL
Results
No. 1/6
No. 2/6
No. 3/6
No. 4/6
No. 5/6
No. 6/6
Note / ID
Hydroquinone
Hydroquinone
Hydroquinone
Hydroquinone
Hydroquinone
Hydroquinone
Rx
R1=
R1=
R1=
R1=
R1=
R1=
Statistics
Rx
R1
Name
Factor
Result
0.9828
0.9822
0.9829
0.9832
0.9833
0.9836
n
6
Unit
-------
Mean Value
0.9830
Table of measured values
Unit
--
Titration curve
s
0.0005
srel[%]
0.05
Method
Method:
User:
M297
Schreiner
001 Title
Typ
Compatible with
ID
Titel
Author
Date / Time
Modified at
Protect
SOP
LabX SOP
002 Sample
Number of IDs
ID 1
Entry Type
Volume [mL]
Density [g/mL]
Correction factor
Temperature [C]
Entry
003 Titration stand
Typ
Titration stand
004 Pump
Auxiliary reagent
Volume [mL]
Condition
005 Dispense
Titrant
Concentration [mol/L]
Volume [mL]
Dosing rate [mL/min]
Condition
006 Stir
Speed [%]
Duration [s]
Condition
007 Titration (EQP)
Titrant
Titrant
Concentration [mol/L]
Sensor
Typ
Sensor
Unit
Temperature aquisition
Temperature aquisition
Stir
Speed [%]
Predispense
Mode
Volume [mL]
Wait time [s]
Control
Control
Titrant addition
dE (set value)
dV (min)
dV (max)
Mode
dE
dt [s]
t(min) [s]
t(max) [s]
Evaluation and Recognition
Procedure
Threshold
Tendency
Ranges
Add. EQP criteria
Termination
At Vmax [mL]
At potential
At Slope
After numbered
of recognized EQPs
Number of EQPs
Combined termination
criteria
Factor cerium sulfate
Accompanying stating
Accompanying stating
Condition
Condition
008 Calculation
Result
Result Unit
Formula
Constant C=
M
z
Decimal places
Result limits
Record statistics
Extra statistical
functions
Condition
009 End of sample
05.04.2007
General titration
T50/70/90
M297
Factor cerium sulfate
Mettler Toledo
05.04.2007
05.04.2007
No
None
1
Hydroquinone
Fixed volume
1.5
1.0
1.0
25.0
Arbitrary
010 Auxiliary Value
Name
Formula H=
Limits
Condition
Manual stand
Manual stand 1
HCl 0.1 mol/L
40
No
1/2 Hydroquinone
0.05
1.5
60.0
No
35
10
No
Cerium sulfate
0.01
mV
DM140-SC
mV
No
35
Volume
5
5
User
Dynamic
8
0.005
0.2
Equlibrium controlled
0.5
2
3
30
Standard
500
Positive
0
No
10
No
No
Yes
1
No
No
No
Factor
---R1=VENDDi*0.05/(VEQ*c)
1
None
None
5
No
Yes
No
No
Cerium sulfate
Mean[R1]
No
No
