Millipore Spectroquant Multy Operating Manual page 209

Standard solution of free chlorine
analogous to DIN EN ISO 7393
Preparation of a KlO stock solution:
3
Dissolve 1.006 g of KlO in 250 ml of distilled water in a
3
calibrated or conformity-checked 1000-ml volumetric flask.
Subsequently make up to the mark with distilled water.
Preparation of a KlO /Kl standard solution:
3
Transfer 7.50 ml (12.50 ml) of the KlO
calibrated or conformity-checked 1000-ml volumetric flask,
add approx. 1 g of Kl and make up to the mark with distilled
water.
1 ml of this solution is equivalent to 0.0075 mg (0.0125 mg) of
free chlorine.
Preparation of the chlorine standard solution:
Pipette 20.0 ml (full pipette) KlO
calibrated or conformity-checked 100-ml volumetric flask, add
2.0 ml of H SO 0.5 mol/l, leave to stand for 1 min, and then
2 4
add NaOH 2 mol/l dropwise (approx. 1 ml) until the solution
just loses its color. Subsequently make up the solution to the
mark with distilled water.
The concentration of the solution is 1.50 mg/l (2.50 mg/l) free
chlorine.
Stability:
The KlO stock solution remains stable for 4 weeks when stored
3
in a cool place (refrigerator). The KlO
be used for 5 hours when stored in a cool place (refrigerator).
The diluted chlorine standard solution is not stable and must
be used immediately.
stock solution to a
3
/Kl standard solution into a
3
/Kl standard solution can
3
Reagents required:
1.02404.0100 Potassium iodate,
volumetric standard
1.05043.0250 Potassium iodide for
analysis EMSURE®
1.09072.1000 Sulfuric acid
0.5 mol/l Titripur®
1.09136.1000 Sodium hydroxide
solution 2 mol/l
Titripur®
1.16754.9010 Water for analysis
EMSURE®
Note
This procedure involves the prepa-
ration according to a standardized
method.
Chapter 5.2 | Page 9 of 23