User Guide

22
Typical Electrode Life
Ambient Temperature 1- 3 years
90 °C Less than 4 months
120°C Less than 1 month
High concentrations of sodium ions interfere
with readings in alkaline solutions; the pH at
which the interference starts to be signifi-
cant depends upon the composition of the
glass. This interference is the alkaline error
and causes the pH to be underestimated.
Hanna's glass formulations have the indi-
cated characteristics.
Alkaline Error
1.0 Mol L
-1
Na
+
0.1 Mol L
-1
Na
+
Sodium Ion Correction for the Glass
at 20-25°C
Concentration pH Error
13.00
13.50
14.00
12.50
13.00
13.50
14.00
0.10
0.14
0.20
0.10
0.18
0.29
0.40