Maintenance
38
Alkali Error with 1.0 mol/L
Na
+
pH
GP
HT
LT
11.5
0.11
0.01
0.46
12.0
0.21
0.06
0.62
12.5
0.32
0.11
0.79
13.0
0.43
0.15
13.5
0.45
0.21
14.0
0.65
0.27
pH Probe
Maintenance
Remove the protective cap off the ORP electrode.
Wash off any SALT DEPOSITS. This generally confi rms the reference junction is
free fl owing.
If the storage cap is dry, the reference junction may be dry also. Soak the
electrode in HI 70300 or HI 80300 storage solution for at least one hour.
Keep the reference electrolyte topped off and the fi ll hole cover off during
operation.
Add HI 7082 or HI 8082 3.5M KCl Electrolyte Solution for double junction
electrodes.
Pretreatment
For a faster response, pretreat the ORP metal surface by soaking it for 15 minutes.
Pretreatment with HI 7091 Reducing Pretreatment Solution, or HI 7092 Oxidizing
Pretreatment Solution can prepare the metal surface for faster electron exchange
with sample. See mV and pH to determine what treatment you should use.
Measurement
Rinse the electrode tip with distilled water. Submerse the tip 3 cm (1¼”) in the
sample and stir gently for a few seconds.
For a faster response and to avoid cross-contamination of the samples, rinse
the electrode tip with a few drops of the sample before taking measurements.
Storage Procedure
To minimize clogging and ensure a quick response time, protect the ORP sensor
by using the storage cap. Add a few drops of HI70300 storage solution to the
cap to keep the reference junction wetted.
Periodic Maintenance
Inspect the sensor and cable. The cable used for connection to the edge must
be intact and with no points of broken insulation.
The ORP metal surface must be smooth with no scratches. The metal surface
can be polished with a fi ne-grained emery cloth or powdered alumina.
Cleaning Procedure
Use diagnostic messages to aid troubleshooting. Several cleaning solutions are
available: See pH cleaning for specifi c contaminants or use a solvent system
capable of dissolving the coating fi rm.
ORP Probe
Maintenance
Summary of Contents for edge PHM4092
Page 1: ...pH...