eutech-instruments silversulfide epoxy Manuale Utente

Silver/Silver Sulfide Electrode 

 

Instruction Manual 

 

22

 
The composition of the liquid junction filling solution in the reference electrode is most important. 
The speed with which the positive and negative ions in the filling solutions diffuse into the sample 
should be as nearly equal as possible, that is, the filling solution should be equitransferent. No 
junction potential can result if the rate of which positive and negative charge carried into the sample 
solution is equal. 
 
Strongly acidic (pH = 0-2) and strongly basic (pH = 12-14) solutions are particularly troublesome to 
measure. The high mobility of hydrogen and hydroxide ions in samples make it impossible to mask 
their effect on the junction potential with any concentration of an equitransferent salt. One must 
either calibrate the electrodes in the same pH range as the sample or use a known increment method 
for ion measurement.  
 
 
TROUBLESHOOTING GUIDE 
  
The goal of troubleshooting is the isolation of a problem through checking each of the system 
components in turn: the meter, the glassware, the electrodes, the standards and reagents, the sample, 
and the technique. 
 

The meter may be checked by following the check-out procedure in the instrument instruction 
manual. 
 

Clean glassware is essential for good measurement. Be sure to wash the glassware well with a mild 
detergent and rinse very well with distilled or deionized water. Clean glassware will drain without 
leaving water droplets behind. 

The electrodes may be checked by using the procedure found in the sections entitled 

Slope Check. 

 

1. 

Be sure to use distilled or deionized water when following the procedures given in 

. 

 
2. 

If the electrode fails to respond as expected, see the sections 

  and 

.  Repeat the slope check. 

 
3. 

If the electrodes still fail to respond as expected,  substitute another silver/sulfide ion 
electrode that is known to be in good working order for the questionable electrode.  If the 
problem persists and you are using an electrode pair, try the same routine with a working 
reference electrode. 

 
4. 

If the problem persists, the reagent may be of poor quality, interference in the sample may 
be present or the technique may be faulty. (See 

Standards and Reagents, Sample

, and 

Technique 

sections below.) 

 
5. 

If another electrode is not available for test purposes, or if the electrode in use is suspect, 
review the instruction manual and be sure to: