Practical Salinity Scale (Unesco 1978); Conductivity To Tds Conversion Factors; Usp/Ep Tables - Mettler Toledo SevenCompact S230 Conductivity Mode D'emploi

11.4 P ractical salinity scale (UNESCO 1978)
The salinity is calculated according to the official definition of UNESCO 1978. Therefore the salin-
ity Spsu of a sample in psu (practical salinity unit) at standard atmospheric pressure is calculat-
ed as fol l ows:
a = 0.0080
0
a = -0.1692
1
a = 25.3851
2
a = 14.0941
3
a = -7.0261
4
a = 2.7081
5
(32.4356 g KCl per 1000 g of solution)
11.5 C onductivity to TDS conversion factors
Conductivity
at 25 °C
84 µS/cm
447 µS/cm
1413 µS/cm
1500 µS/cm
8974 µS/cm
12.880 µS/cm
15.000 µS/cm
80 mS/cm
11.6 U SP/EP tables
Conductivity requirements (µS/cm) for USP / EP (highly purfied water) / EP (purfied water)
Temperature
[°C]
0
5
10
15
20
25
30
35
40
45
50
46 Appendix
b = 0.0005
0
b = -0.0056
1
b = -0.0066
2
b = -0.0375
3
b = 0.0636
4
b = -0.0144
5
TDS KCl
ppm value factor
40.38 0.5048
225.6 0.5047
744.7 0.527
757.1 0.5047
5101 0.5685
7447 0.5782
8759 0.5839
52.168 0.6521
USP EP
(highly purfied water)
[µS/cm] [µS/cm]
0.6 0.6
0.8 0.8
0.9 0.9
1.0 1.0
1.1 1.1
1.3 1.3
1.4 1.4
1.5 1.5
1.7 1.7
1.8 1.8
1.9 1.9
k = 0.00162
TDS NaCl
ppm value factor
38.04 0.4755
215.5 0.4822
702.1 0.4969
737.1 0.4914
4487 0.5000
7230 0.5613
8532 0.5688
48.384 0.6048
EP
(purfied water)
[µS/cm]
2.4
-
3.6
-
4.3
5.1
5.4
-
6.5
-
7.1