Sample Preparation; Response Times - Xylem WTW Ag/S 800 DIN Mode D'emploi

Ag/S 800
+
Ag measurement
2-
S measurement
ba15350d04 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

Add 2 % ISA/FK solution. This sample conditioning solution creates optimum
conditions for measuring. It provides a constant ionic strength and similar
diffusion potentials at the reference electrode in standard solution and test
sample.
Add 50 % SAOB II solution.
Preparation of the SAOB II solution:
 200 ml/l 10 molar NaOH
 35 g/l ascorbic acid
 67 g/l EDTA
A freshly prepared SAOB II solution (Sulfide Anti-Oxidant Buffer)
is colorless or slightly yellowish brown. If the solution has already
strongly oxidized its color is dark brown. The solution can no lon-
ger be used.
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
Sample preparation
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