wtw PhotoLab S6 Operating Instructions Manual page 23

Instructions for the Preparation of Standard Solutions
Standard solution of free chlorine
acc. to DIN EN ISO 7393
Preparation of a KlO
In a 1000-ml volumetric flask dissolve 1.005 g
of KlO art.1.02404, in 250 ml of distilled water.
3,
Subsequently make up to the mark with distilled
water.
Preparation of a KlO
Transfer 10.0 ml of the KlO
1000-ml volumetric flask, add approx. 1g of Kl,
art. 1.05043, and make up to the mark with
distilled water (this solution must be prepared
freshly).
1 ml of this solution is equivalent to 0.010 mg
of chlorine.
Preparation of the chlorine standard solution:
Pipette 20 ml KlO /Kl standard solution into a
3
100-ml volumetric flask, add 2.0 ml of H
0.5 mol/l, art. 1.09072, leave to stand for 1 min,
and then add NaOH 2 mol/l, art. 1.09136,
dropwise (approx. 1 ml) until the solution just
loses its colour. Subsequently make up the
solution to the mark with distilled water.
The concentration of the solution is 2.00 mg/l
chlorine.
Stability:
The KlO stock solution remains stable for 4
3
weeks when stored in a cool place. The KlO
standard solution can be used for 5 hours when
stored in a cool place. The dilute chlorine
standard solution remains stable for a maximum
of 5 minutes.
Reagents required:
1.02404.0100 Potassium iodate, volum. standard
1.05043.0250 Potassium iodide GR
1.09072.1000 Sulfuric acid 0.5 mol/l
1.09136.1000 Sodium hydroxide solution 2 mol/l
Release 07/03
stock solution:
3
/Kl standard solution:
3
stock solution to a
3
SO
2 4
3
Standard solution of free chlorine
Preparation of a standard solution:
Dissolve 1.85 g of dichloroisocyanuric acid,
sodium salt, GR with DI water in a calibrated or
conformity-checked 1-l volumetric flask and make
up to the mark. The stock solution prepared
according to this procedure has a concentration
of 1000 mg/l free chlorine.
Further investigational concentrations may be
prepared from this stock solution by diluting
accordingly.
Stability:
When stored in a cool place (refrigerator), the
stock solution and the diluted investigational
solutions remain stable for one day.
Reagents required:
1.02426.0250 Dichloroisocyanuric acid,
1.16754.9010 Water GR
Standard solution of total chlorine
Preparation of a standard solution:
Dissolve 4.00 g of chloramine T GR with DI water
in a calibrated or conformity-checked 1-l volu-
/Kl
metric flask and make up to the mark. The stock
solution prepared according to this procedure has
a concentration of 1000 mg/l total chlorine.
Further investigational concentrations may be
prepared from this stock solution by diluting
accordingly.
Stability:
When stored in a cool place (refrigerator), the
stock solution and the diluted investigational
solutions remain stable for one day.
Reagents required:
1.02426.0250 Chloramine T GR
1.16754.9010 Water GR
sodium salt, GR
XXI