2010.02
DATA No.D-8
Page 1 / 1
Weekly Application Note
Category
Potentiometric Titrator COM series
Sulfite ions in gold plating solution
Plating
by Redox titration method
Referenced methods
sulfite ions, gold plating solution, redox titration
Key words;
Outline
The determination of sulfite ions contained in gold plating solution can be performed by the
following procedure:
Add a certain amount of iodine solution to the sample solution to react with sulfite ions in the
sample as indicated formula (1). Æ After acidifying with hydrochloric acid, titrate the remaining
iodine with sodium thiosulfate solution as shown in formula (2) by the redox back titration.
SO32-
+
I2
2Na2S2O3
+
I2
Æ
SO42Æ
+
2NaI
2H+
+
2I-
･･･ (1)
Na2S2O6
･･･ (2)
+
Reagents
Titrant
: 0.1 mol/L sodium thiosulfate standardized solution
Additve
:
0.05 mol/L iodine solution
1 mol/L hydrochloric acid (for acidification)
Instruments & Electrodes
Recommended automatic titrator
More automated system!
COM-1700S (High-end potentiometric titrator, stand-alone)
COM-300A (Compact and simple titrator)
COM-1700S + 2 additional burets B-1700-20
(*To automatically deliver iodine solution and hydrochloric acid)
・Platinum electrode PR-301 (P/N D231244-A)
・Reference electrode RE-201 (standard accessory)
Additional burets
▲COM-1700S w/ additional burets
Built-in Thermal Printer
▲COM-300A
2010.02
DATA No.D-8
Page 2 / 2
Condition parameters (example)
Master file 1
1+2+3
*COM-1700 *automatically dispensing I2 and HCl3
Blank
Master file 2
4+5+6
Measurement
Condition 1
(Dispensing 10mL of I2)
Condition 4
(Dispensing 10mL of I2)
Method
Disp
Method
Disp
Buret No.
2
Buret No.
2
S-Timer
0 sec
S-Timer
0 sec
Disp Vol.
10 mL
Disp Vol.
10 mL
Condition 2
(Dispensing 5mL of HCl)
Condition 5
(Dispensing 5mL of HCl)
Method
Disp
Method
Disp
Buret No.
3
Buret No.
3
S-Timer
5 sec
S-Timer
60 sec
Disp Vol.
5 mL
Disp Vol.
5 mL
Condition 3
(Blank)
Condition 6
(Dispensing 5mL of HCl)
Method
AUTO
Method
Auto
Buret No.
1
Mode No.
8
Buret No.
1
Mode No.
8
Amp. No.
2
Pre Int
0 sec
Amp No.
2
Pre Int
0 sec
Meas Unit
mV
Del K
5
Meas Unit
mV
Del K
5
S-Timer
10 sec
Del Sens
0 mV
S-Timer
10 sec
Del Sens
0 mV
CP mL
0 mL
Int Time
5 sec
CP mL
0 mL
Int Time
5 sec
T-Timer
0 sec
Int Sens
3 mV
T-Timer
0 sec
Int Sens
3 mV
DP mL
0 mL
Brt Speed
2
DP mL
0 mL
Brt Speed
2
End Sens
300
Pulse
40
End Sens
100
Pulse
40
Over mL
0.3 mL
Over mL
0 mL
Max volume
20 mL
Max Volume
20 mL
Unit
D
Unit
g/L
Size
0 mL
Size
1 mL
Blank
0
Blank
Result value of blank titration
Molarity
0.1
Molarity
0.1
Factor
Titre of the titrant
Factor
Titer of the titrant
K
0
K
40.03
L
0
L
0
Formula
D
Formula
(B-D) x F x M x K / S
*When manually adding I2 and HCl, only condition 3 and 6 are used.
For more information, please feel free to contact:
Hiranuma Sangyo Co., Ltd.
1739 Motoyoshida-cho, Mito, Ibaraki 310-0836
Phone: +81-29-247-7343
/
JAPAN
Fax: +81-29-247-0381
URL http://www.hiranuma.com
E-mail [email protected]
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