Hanna Instruments HI 9321 - Manual (Page 16)

1 6
pH VALUES AT VARIOUS
TEMPERATURES
TEMP pH VALUES
°C °F 4.01 6.86 7.01 9.18 10.01
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
32
41
50
59
68
77
86
95
104
113
122
131
140
149
158
4.01
4.00
4.00
4.00
4.00
4.01
4.02
4.03
4.04
4.05
4.06
4.07
4.09
4.11
4.12 6.98
6.95
6.92
6.90
6.88
6.86
6.85
6.84
6.84
6.83
6.83
6.84
6.84
6.85
6.85 7.13
7.10
7.07
7.04
7.03
7.01
7.00
6.99
6.98
6.98
6.98
6.98
6.98
6.99
6.99 9.46
9.39
9.33
9.27
9.22
9.18
9.14
9.10
9.07
9.04
9.01
8.99
8.97
8.95
8.93 10.32
10.24
10.18
10.12
10.06
10.01
9.96
9.92
9.88
9.85
9.82
9.79
9.77
9.76
9.75
Temperature has an effect on pH. The calibration buffer solutions are
affected by temperature changes to a lesser degree than normal
solutions. During calibration the meter will automatically calibrate to
the pH value corresponding to the measured or set temperature.
For instance, if the buffer temperature is 25°C, the display will show
pH 4.01 or 7.01 or 10.01. If the buffer temperature is 20°C, it will
show pH 4.00/7.03/10.06 or at 50°C, the display will show
pH 4.06/6.98/9.82.
TAKING REDOX MEASUREMENTS
An optional ORP electrode must be used to perform ORP measure-
ments (see page 33).
Oxidation-reduction potential (REDOX) measurements provide the
quantification of the oxidizing or reducing power of the sample tested.
To correctly perform a redox measurement, the surface of the ORP
electrode must be clean and smooth.
When not in use, the tip of the electrode should be kept moist and
safe from any mechanical stress which might cause damage to the
glass/platinum sensing element.