23
Thermo Scientific Orion Star A113 Benchtop & Star A123 Portable Dissolved Oxygen Meters
Chapter 7 Appendix
Salinity Correction
Since the presence of dissolved salts limits the amount of oxygen that can dissolve in water, the relationship between
oxygen concentration and partial pressure varies with sample salinity. The meter default has a salinity correction factor
of 0. To compensate for variations in ionic concentration, use the sample’s conductivity measurement to determine the
salinity of the sample. Enter this value in parts per thousand (ppt) to ensure standardized DO measurements.
Conductivity
at 20 °C
(mS/cm)
Salinity
Correction
Value (ppt)
Conductivity
at 20 °C
(mS/cm)
Salinity
Correction
Value (ppt)
Conductivity
at 20 °C
(mS/cm)
Salinity
Correction
Value (ppt)
5
3
20
13
35
25
6
4
21
14
36
25
7
4
22
15
37
26
8
5
23
15
38
27
9
6
24
16
39
28
10
6
25
17
40
29
11
7
26
18
42
30
12
8
27
18
44
32
13
8
28
19
46
33
14
9
29
20
48
35
15
10
30
21
50
37
16
10
31
22
52
38
17
11
32
22
54
40
18
12
33
23
56
42
19
13
34
24
This table was calculated from the International Oceanographic Tables, Vol. 1, National Institute of Oceanography
of Great Britain, Womley, Godaming, Surrey, England and Unesco, Paris 1971.
