Thermo Fisher Scientific CyberScan pH 10/pH 100 - Manual (Page 52)

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11 ELECTRODE CARE
11.1 Electrode Maintenance
pH electrodes are susceptible to dirt and contamination and need to be cleaned regularly
depending on the extent and condition of use.
11.1.1 Storage
The best results, always keep the pH bulb wet, preferably in pH 4 buffer with 1/100 part of
saturated KCl. Other pH buffers or tap water are also acceptable storage media, but avoid
storage in de-ionized water. The protective rubber cap filled with the buffer solution provides
ideal storage for long periods.
11.1.2 After Use
After measurement is complete, follow the sequence elaborated below for storage.
1. Wash the electrode and reference junction in deionized water.
2. Close the refilling hole by returning its rubber sleeve or stopper cap (Necessary for only
refillable electrodes).
3. Store the electrode as mentioned above (Storage section 11.1.1).
11.1.3 Electrolyte Replacement (for refillable electrodes only)
The reference electrolyte needs to be refilled when the electrode has been used for an
extended period, or when the internal electrolyte has dried up. To accomplish this, follow the
procedure detailed below.
a) Remove the protective rubber cap or sleeve
Remove the protective rubber sleeve to expose the filling port of the electrode. Remove the
old reference electrolyte with a syringe and a flexible tube.
b) Fill the new reference electrolyte
Add in fresh electrolyte until it reaches the level of refilling port. The reference electrolyte used
should be 4M KCl. Replace the rubber sleeve.
c) Re-use the electrode
Rinse the liquid junction with deionized water and tap dry.
NOTE: If these steps fail to restore normal electrode response, you may attempt to rejuvenate
it. (See section 11.4 on Rejuvenation Procedure).