Chlorine Dioxide, 0.02 - 11 Mg/L Clo; Chlorine Dioxide Analysis; Chlorite, Cl 2 Free, Cl - Grundfos DIT-L Bedienungsanleitung

7.4 Chlorine dioxide, 0.02 - 11 mg/l ClO

Start the photometer and select method.
See section 6.1 Start.
7.4.1 Important notes
• Vial cleaning:
As many household cleaners (e.g. dishwasher detergent)
contain reducing substances, the subsequent determination of
chlorine dioxide may show lower results. To avoid any
measurement errors, only use glassware free of chlorine
demand.
Preparation: Put all applicable glassware into sodium
hypochlorite solution (0.1 g/l) for one hour, then rinse all
glassware thoroughly with deionised water.
• When preparing the sample, the escape of chlorine dioxide
gas, e.g. by pipetting or shaking, must be avoided. The
analysis must take place immediately after taking the sample.
• The DPD colour development is carried out at a pH value of
6.2 to 6.5. The reagent tablet therefore contains a buffer for
the pH adjustment.
Strong alkaline or acidic water samples must be adjusted
between pH 6 and pH 7 before the tablet is added
(use 0.5 mol/l sulphuric acid and 1 mol/l sodium hydroxide,
respectively).
• For concentrations between 11.0 and 19 mg/l, the photometer
shows that the measuring range is exceeded [Hi].
Concentrations above 19 mg/l chlorine dioxide can lead to
results showing 0 mg/l. In this event, the water sample must
be diluted with water free of chlorine dioxide. 10 ml of the
diluted sample should be mixed with the reagent and the
measurement repeated (plausibility test).
• All oxidising agents in the samples interfere as they react in
the same way as chlorine dioxide.
7.4.2 In the absence of chlorine
1. Fill a clean vial (∅24) with 10 ml of the water
0.0.0
sample and perform zero setting. See
section 6.2 Zero
2. Remove the vial from the sample chamber
and empty it, leaving a few drops in the vial.
3. Add one DPD No. 1 tablet (No 95727747)
straight from the foil to the water sample and
crush the tablet using a clean stirring rod.
4. Add the water sample to the 10 ml mark.
5. Close the vial tightly with the cap and swirl
gently several times until the tablet is
dissolved.
6. Place the vial correctly in the sample
chamber. See fig. 3.
7. Press the [Zero/Test] key.
Zero/Test
The method symbol flashes for
CLO2
approx. 3 seconds.
"RESULT" appears in the display in mg/l
RESULT
chlorine dioxide.
CLO2
2
setting.
7.4.3 In the presence of chlorine
1. Fill a clean vial (∅24) with 10 ml of the water
0.0.0
sample and perform zero setting.
See section
2. Remove the vial from the sample chamber
and empty it, leaving a few drops in the vial.
3. Add one DPD No. 1 tablet (No 95727747)
straight from the foil to the water sample and
crush the tablet using a clean stirring rod.
4. Fill a second clean vial with 10 ml of the
water sample.
5. Add one Glycine tablet (No 95727752)
straight from the foil and crush the tablet
using a clean stirring rod.
6. Transfer the contents of the second vial into
the prepared vial.
7. Close the vial tightly with the cap and swirl
gently several times until the tablet is
dissolved.
8. Place the vial correctly in the sample
chamber. See fig. 3.
9. Press the [Zero/Test] key.
Zero/Test
The method symbol flashes for
CLO2
approx. 3 seconds.
"RESULT" appears in the display in mg/l
RESULT
chlorine dioxide.
7.4.4 Tolerances
0 - 1.9 mg/l: ± 0.1 mg/l
> 1.9 - 3.8 mg/l: ± 0.2 mg/l
> 3.8 - 5.7 mg/l: ± 0.4 mg/l
> 5.7 - 7.6 mg/l: ± 0.6 mg/l
> 7.6 - 11.0 mg/l: ± 0.8 mg/l
7.5 Chlorine dioxide analysis (ClO
chlorite, Cl free, Cl combined)
2 2
0.01 - 6 mg/l
7.5.1 Important notes
This analysis is used for differentiated determination of:
• chlorine dioxide
• chlorite
• free chlorine
• combined chlorine
The measurements are performed with method "CL 6" as the
photometer doesn't supply a specific method for the
determination of these parameters. The values determined during
measurement (see section 7.5.2
effective quantities of certain parameters. The effective quantities
have to be calculated out of the determined values after
measurement. (See section 7.5.3
The values of tolerance (see section
methods and reagents) apply to the individual
Caution
measurement. For calculation with multiple values,
be aware of error propagation!
6.2 Zero setting.
,
CL 6
2
Measurements) are not the
Calculation)
7.2 Table of
11