cytiva pH/C-902 Instrukcja obsługi - Strona 5

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Storage of the pH electrode
Step
Action
1
Always dismount the pH electrode from the flow cell and fit the
end cover filled with a 1:1 mixture of pH 4 buffer and 1 M KNO
Do NOT store in water only.
2
Replace the pH electrode with the pH plug in the flow cell.
Regeneration of the pH electrode
If the electrode has dried out, immerse the lower end of the electrode
in buffer with a 1:1 mixture of pH 4 buffer and 1 M KNO
Storage of the conductivity flow cells
•
Overnight: The conductivity cell can be left filled with a buffer.
•
Weekend or long-term storage: Flush the conductivity cell
with water and fill the cell with 20% ethanol.
Restart after power failure
If the power supply to the instrument is interrupted, the instrument
automatically restarts itself when the power is resumed. All set
values are retained in the instrument.

Maintenance

WARNING
Disconnect the power supply before attempting
to replace any item on the instrument during
maintenance.
Only personnel authorized by Cytiva may service
the instrument.
CAUTION
Only spare parts approved or supplied by Cytiva
may be used for maintaining and servicing the
instrument.
Periodic maintenance
Interval
Every 6 months or more often if
required
When required
See procedures below
Cleaning the flow cell
Step
Action
1
Remove the pH electrode and replace it with the pH plug in the
pH flow cell.
2
Pump a cleaning or sanitizing agent through the flow cells.
The standard recommendation is to pump 1 M NaOH for 30 minutes
and then wash out with buffer.
pH/C-902 Instruction 14003958 AB
overnight.
3
Action
Change pH electrode
Clean the conductivity cell
Clean the pH electrode
WARNING
NaOH is corrosive and therefore dangerous to
health. When using hazardous chemicals avoid
spillage and wear protective glasses and other
.
3
suitable personal protection equipment.
Cleaning the pH electrode
Note: The pH electrode has a limited life length and should be
replaced every six months or when the response time is slow.
Use one of the following procedures to clean the electrode to
improve the response:
Deposit
Salt
Oil or Grease Films Wash electrode tip in a liquid detergent and
Protein
If these procedure fail to rejuvenate the electrode, the problem is
most likely a clogged liquid junction.
Step
Action
1
Heat a 1 M KNO
2
Place the electrode tip in the heated KNO
3
Allow the electrode to cool while immersed in the KNO
solution before retesting.
If these steps fail to improve the response of the electrode, it should
be replaced.
Changing the pH electrode
See Section
Preparing and inserting the pH electrode,
Cleaning the conductivity flow cell
If the conductivity measurements are not comparable to previous
results, the electrodes in the flow cell may be contaminated and
require cleaning. To clean the flow cell:
Step
Action
1
Pump 15 ml of 1 M NaOH at 1 ml/min through the flow cell
either by using the pump or a syringe.
2
Leave it for 15 minutes.
3
Rinse thoroughly with 50 ml de-ionized water.
Note: If the flow cell is totally blocked, the blockage can be broken
using a thin needle or a piece of string with a diameter of less
than 0.8 mm.
Procedure
Dissolve the deposit by immersing the
electrode first in 0.1 M HCl, then in
0.1 M NaOH, and again in 0.1 M HCl. Each
immersion should last for 5 minutes. Rinse
the electrode tip in distilled water between
each solution.
water. If film is known to be soluble in a
particular organic solvent, wash with this
solvent. Rinse electrode tip in distilled water.
Dissolve the deposit by immersing the
electrode in a 1% pepsin solution, in
0.1 M HCl, for 5 minutes, followed by a
thorough rinsing with distilled water.
solution to 60 – 80°C.
3
solution.
3
3
.
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