Ph Measurement - Lovibond Tintometer SD 335 Multi Bedienungsanleitung

(3)
a) b)
(4)
(5)
Note: automatic temperature compensation during calibration
Both the signal of the pH electrode and the pH value of the calibration solutions depend
on the temperature. If a temperature sensor is connected, the temperature infl uence of the
electrode is automatically compensated both during measurement and during calibration.
Otherwise, the actual temperature of the buffer in question should be entered as accurately as
possible. If standard or DIN buffers are used, the temperature infl uences of the buffers are also
compensated. With manual buffer selection, the pH values of the buffers should be entered
at the associated temperature in order to achieve as accurate a calibration process as possible.

5.3 pH measurement

pH measurement is a very precise but also sensitive measurement. The signals measured are
very weak (high Ohm), especially if measurements are carried out in low-ion media. Care
should therefore be taken to ensure that
• Faults, such as those caused by electrostatic charge, are avoided
• Plug contacts are kept clean and dry
• Electrodes are not immersed beyond the length of the shaft
• The electrode is calibrated suffi ciently often – the frequency of calibration depends
on the electrode and its use
• A suitable electrode is used
50
Rinse the electrode with distilled or deionised water and dab the
electrode carefully with a paper towel.
Immerse the pH electrode incl. temperature sensor in the calibration
solution. Ensure suffi cient fl ow, e.g. by
a) using a magnetic stirrer with agitator (recommended)
b) Swirl the pH electrode in the solution.
Interrupt the stirring and start the calibration with the F2 key.
(If the buffer solution is not recognized, the instrument will
prompt you to manually enter the pH value of the solution.
The calibration can then be continued.)
Either continue the calibration with the next point (F2 key)
and repeat the steps from (3) or exit the calibration mode (F1 key).
When calibration is complete, the sensor status is evaluated on
the basis of the offset (pH 7) and slope (pH 4, 10) and indicated
in %.
(Example from 3-point calibration)
SD_335_1 06/2020