OHAUS ST300D-G, Instruction Manual

Page: 16 / 63

EN-14 STARTER 300C Portable Conductivity Meter
7 APPENDIX
7.1 Conductivity standards
T(°C) 10
μ
S/cm 84
μ
S/cm 1413
μ
S/cm 12.88 mS/cm
5 6.1
μ
S/cm 53
μ
S/cm 896
μ
S/cm 8.22 mS/cm
10 7.0
μ
S/cm 60
μ
S/cm 1020
μ
S/cm 9.33 mS/cm
15 8.0
μ
S/cm 68
μ
S/cm 1147
μ
S/cm 10.48 mS/cm
20 9.0
μ
S/cm 76
μ
S/cm 1278
μ
S/cm 11.67 mS/cm
25 10.0
μ
S/cm 84
μ
S/cm 1413
μ
S/cm 12.88 mS/cm
30 11.0
μ
S/cm 92
μ
S/cm 1552
μ
S/cm 14.12 mS/cm
35 12.1
μ
S/cm 101
μ
S/cm 1667
μ
S/cm 15.39 mS/cm
7.2 Examples of temperature coefficients (
α
-value)
Substance at 25 °C Concentration [%] Temperature coefficient
α
[%/°C]
HCl 10 1.56
KCl 10 1.88
CH3COOH 10 1.69
NaCl 10 2.14
H2SO4 10 1.28
HF 1.5 7.20
α
-coefficients of conductivity standards for a calculation to reference temperature of 25°C
Standard
Measurement
temp.: 15°C Measurement
temp.: 20°C Measurement
temp.: 30°C Measurement
temp.: 35°C
84
μ
S/cm 1.95 1.95 1.95 2.01
1413
μ
S/cm 1.94 1.94 1.94 1.99
12.88 mS/cm 1.90 1.89 1.91 1.95
7.3 Conductivity to TDS conversion factors
Conductivity
At 25 °C
TDS KCl TDS NaCl
ppm value Factor ppm value Factor
84
μ
S 40.38 0.5048 38.04 0.4755
447
μ
S 225.6 0.5047 215.5 0.4822
1413
μ
S 744.7 0.527 702.1 0.4969
1500
μ
S 757.1 0.5047 737.1 0.4914
8974
μ
S 5101 0.5685 4487 0.5000
12.88
μ
S 7447 0.5782 7230 0.5613
15
μ
S 8759 0.5839 8532 0.5688
80 mS 52.168 0.6521 48.384 0.6048
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