Xylem ISE Electrodes Ag-S 60 - Handbuch (Seite 15)

15
Minimum depth of immersion:
The diaphragm must be covered
Maximum depth of immersion:
Approx. 1 cm below the fluid level of the bridge electrolyte
Before Measuring
x Before use, condition the combination electrode or
electrodes respectively for approx. 5 min. in standard
solution.
x Remove any air bubbles in the bridge electrolyte by
slightly knocking against the shaft.
x Calibrate according to the operating manual of the meter
and the analysis specification.
Sample preparation
Ag
+
measurement 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 and test sample.
S
2-
measurement Add 50 % SAOB II solution.
Preparation of the SAOB II solution:
x
200 ml/L 10 molar NaOH
x
35 g/L ascorbic acid
x
67 g/L EDTA
Note 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. In this
case it can no longer be used.
If you would like to have more detailed information
concerning sample preparation and measuring procedures,
SI Analytics provides a large number of application reports
for various applications.