Crison 50 21 T Manual Usuario página 10

pH electrode 50 21 T
Introduction
The 50 21 T is a pH electrode with built-in A.T.C. Pt 1000, suitable
for difficult samples.
Electrode preparation
Remove the storage protector containing electrolyte
Remove the air bubbles that are inside the membrane
They can be removed by shaking the electrode as a clinical
thermometer.
Remove the cap from the electrolyte filling port
Before measuring, slide the plastic ring and return it to its original posi-
tion, by pressing softly, to ensure the electrical contact, see fig A. If it is
necessary, refill with reference electrolyte.
Calibration
See pH-meter instruction manual.
Measurements. Recommendations
• During calibration and measurement the buffers and the samples
must be slightly stirred. The stirring speed should be identical in
both cases.
• The sample must cover the electrode's diaphragm
• After measurement, immediately rinse the electrode with distilled
water. Dry it with soft tissue, only by contact, without rubbing.
• Between measurements the electrode's membrane should be im-
mersed in aqueous solution. The most appropriate place is the
storage protector with some electrolyte.
Do not leave the electrode immersed in distilled water.
Maintenance
• Periodically refi ll the electrode with electrolyte. Maintain the level
as high as possible
• Maintain the membrane's surface clean
or knocking.
• When an electrode gets contaminated, the simple rinsing with dis-
tilled water is not suffi cient. The most suitable cleaning solution
is one which acts in a more selective way over the contamination
(look for CRISON regeneration solutions).
• Re-hydration. A "dry" electrode recovers by immersing it in CRI-
SON cleaning electrode solution, code 96 00, or in diluted HCl
solution for several hours. It is recommended to read the informa-
tion supplied with the electrode's regenerating solutions.
Troubleshooting
... always measures the same pH value.
Short circuit in the electrode or cable.
Substitute the electrode.
... unstable reading.
Air bubble in the membrane.
Shake the electrode as a thermometer.
... impossible to perform calibration.
... very slow response.
Dirt on the diaphragm or the membrane.
De-hydrated membrane.
Electrode ageing or wear.
Clean, regenerate or substitute the electrode.
Storage
Place the electrode in the storage protector
(KCl 3M).
Close the refilling port with the stopper
10
.
.
.
.
. Protect it from friction
with Crisolyt
.
.