Horiba Scientific 6561S-10C, Инструкция по эксплуатации

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
How to prepare a sample solution
Either use TISAB ( Page 21), or adjust the pH of the sample solution
as described in the following procedure.

If the pH of the sample solution exceeds 8, adjust the pH in the range of
5 to 8 by adding hydrochloric acid.

If the pH of the sample solution is less than 5, adjust the pH in the range
of 5 to 8 by adding sodium hydroxide.

Impact of temperature
The potential gradient measured by the ion electrode method is impacted
by the temperature of the sample solution in accordance with the Nernst
equation. The higher the temperature is, the larger the potential gradient is.
The lower the temperature is, the smaller the potential gradient is.
The standard solution in calibration and the sample solution in
measurement shall have almost the same temperature. Match the
temperature as close as possible.
Table 5 Relationship between temperature of ion selective electrode and theoretical slope
The optimal way to minimize the impact of temperature on the
measurement of the F
-
concentration is to reduce the difference between
the temperature of the standard solution in calibration and the temperature
of the sample solution in measurement to ±1°C.
The following table shows the change in the potential gradient of the
fluoride ion selective electrode depending on the temperature.
Unit: mV/decade (mV/concentration change of 10 times)
Temperature (°C)
0 10 20 25 30 40 50
Theoretical
slope
Monovalent
ions
54.20 56.18 58.16 59.16 60.15 62.13 64.11
Divalent
ions
27.10 28.09 29.08 29.58 30.07 31.07 32.06