Sample Preparation; Response Times; Interferences - Xylem wtw F 800 DIN Operating Manual

F 800
ba15358d04 12/2021
The conditioning time depends on the previous history of
the ion sensitive electrode. To achieve a good responding
behavior, the concentration of the standard solution should
be similar to the concentration expected of the test sample.
During commissioning and after long periods of storage:
condition the electrode overnight.
Connect the electrode(s) to the meter and switch to the
measured value display (see operating manual of the
meter). The ion sensitive electrode is sufficiently condi-
tioned when the measured value no longer changes consid-
erably under otherwise constant conditions (temperature,
composition of the solution).
2 Remove any air bubbles in the bridge electrolyte by slightly knocking
against the shaft.
3 Calibrate according to the operating manual of the meter and the
analysis specification.

Sample preparation

Mix the standard solutions and test samples 1:1 with TISAB sample condi-
tioning solution. This sample conditioning solution creates optimum condi-
tions for measuring. It provides a constant ionic strength and similar diffusion
potentials at the reference electrode in standard solution and test sample.
If you would like to have more detailed information concerning
sample preparation and measuring procedures, WTW provides a
large number of application reports for various applications.

Response times

The response time depends on the concentration range. It is
 several seconds at high concentrations,
 several minutes near the detection limit.
The measured value is stable if the value does not change by more than
0.1 mV within 30 seconds.

Interferences

 pH values < 5 or > 7
Sample preparation
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