IM 12B03D02-01E
9-4
9
.
Technical Information
9.3 Temperature Compensation
In equation 9.3, 2.3026RT/F represents the emf per pH unit and varies depending on
temperature.
Table 9.1 EMF per pH (values of 2.3026RT/F)
Temperature
(
°
C)
2.3026RT/F
(mV)
Temperature
(
°
C)
2.3026RT/F
(mV)
Temperature
(
°
C)
2.3026RT/F
(mV)
0
54.20
35
61.14
70
68.09
5
55.19
40
62.14
75
69.08
10
56.18
45
63.13
80
70.07
15
57.18
50
64.12
85
71.07
20
58.17
55
65.11
90
72.06
25
59.16
60
66.11
95
73.05
30
60.15
65
67.10
100
74.04
Table 9.1 presents the relationship between the temperature and the emf per pH unit,
and the relationship between the pH and the emf at each temperature is shown in
Figure 9.4. Measurement without temperature compensation will result in measured
pH values including errors as shown in Table 9.2.
The PH71 meter automatically modifies the calibration line according to the
temperature measured by the temperature element incorporated in an electrode
(except needle type and test tube size pH sensors).
0°C
20°C
60°C
80°C
-500
0
+500
pH7
pH2
mV
4
6
8 10 12 pH14
F0904.ai
Figure 9.4 pH vs EMF at Each Temperature
