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Silver/Silver Sulfide Electrode 

 

Instruction Manual 

 

14

 

 
The minimum sulfide sample concentration for this method is 1.0X10-

5

M. The titrant to be used is 

a lead perchlorate standard solution. 

1. 

Using Eutech Lead Perchlorate Solution, 0.1M, Code No. EC-SCS-PB1-BT, prepare a lead 
titrant that is about 10-20 times as concentrated as the expected sample concentration by 
dilution. 

 
2. 

Dilute 25 ml of the sample with 25 ml of SAOB in a 150 ml beaker. Place the beaker on 
the magnetic stirrer and begin stirring. Lower the tips of the electrodes into the solution. 

 
3. 

Using a 10 ml burette, add titrant in 0.5-1.0 ml increments. Record the mV reading against 
the volume of titrant added. As the mV potential change increases, add smaller increments, 
down to 0.1-0.2 ml increments. Continue to add titrant and record the mV potential against 
the volume until little change is noted in the mV reading even when adding 0.5-1.0 ml 
increments. 

 
4. 

Using linear graph paper, plot the mV readings (y-axis) against the volume (x-axis).  The 
end point is determined at the steepest slope on the titration curve as illustrated in Figure 3. 

 

5. 

The sample concentration, Cs, is calculated before the dilution with SAOB, as follows: 

 
                      Cs = (Vt/Vs) Ct 
 

     where 

                      Vs = sample volume before dilution (25 ml) 
                      Vt = titrant volume at endpoint 
                      Ct = titrant concentration (M) 

 
 

 
Eutech Silver/Sulfide Ion Electrode is a highly sensitive endpoint detector for silver titration with a 
halide standard solution. It can also be used as an indicator for halide titration with a silver standard 
solution.