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Cleaning Procedure
Use diagnostic messages to aid pH electrode troubleshooting. Several cleaning solutions are
available:
• General – Soak in Hanna
Instruments
HI7061
or
HI8061
General Cleaning Solution for
approximately ½ hour.
• Protein –Soak in Hanna Instruments
HI7073
or
HI8073
Protein Cleaning Solution for
15 minutes.
• Inorganic – Soak in Hanna Instruments
HI7074
Inorganic Cleaning Solution for
15 minutes.
• Oil/grease – Rinse with Hanna Instruments
HI7077
or
HI8077
Oil and Fat Cleaning
Solution.
Note: After performing any of the cleaning procedures, rinse the electrode thoroughly with
distilled water, refill the reference chamber with fresh electrolyte (not necessary for gel-filled
electrodes) and soak the electrode in HI70300 or HI80300 Storage Solution for at least
1 hour before taking measurements.
Temperature Correlation For pH Sensitive Glass
Verify the temperature range by reading the limits on electrodes cap. The pH electrode’s life also
depends on the temperature that is used. If constantly cycled between two temperatures, the life of
the electrode is drastically reduced.
Alkaline Error
High concentrations of sodium ions interfere with readings in alkaline solutions. The pH at which the
interference starts to be significant depends upon the composition of the glass. This interference is
called alkaline error and causes the pH to be underestimated. Hanna Instruments’s glass formulations
have the indicated characteristics. Sodium Ion error for various glass types at ambient temperature:
MAINTENANCE
Alkali Error with 0.1 mol /L Na
+
pH
GP
HT
LT
12.5
0.11
0.05
0.28
13.0
0.23
0.11
0.35
13.5
0.35
0.16
0.45
14.0
0.48
0.20
0.54
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
Summary of Contents for HI 2002
Page 1: ...INSTRUCTION MANUAL pH...