Tintometer Lovibond MD 200 Mode D'emploi page 26

Methods
GB
Notes:
1. Vial cleaning:
As many household cleaners (e.g. dishwasher detergent) contain reducing substances,
the subsequent determination of Ozone may show lower results. To avoid any measure-
ment 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.
2. Preparing the sample:
When preparing the sample, the lost of Ozone, e.g. by pipetting or shaking, must be
avoided. The analysis must take place immediately after taking the sample.
3. The DPD colour development is carried out at a pH value of 6.2 to 6.5. The reagents
therefore contain a buffer for the pH adjustment.
Strong alkaline or acidic water samples must be adjusted between pH 6 and pH 7 before
the reagent is added (use 0.5 mol/l Sulfuric acid resp. 1 mol/l Sodium hydroxide).
4. Exceeding the measuring range:
Concentrations above 6 mg/l Ozone can lead to results showing 0 mg/l. In this case, the
water sample must be diluted with water free of Ozone and the measurement repeated.
5. Oxidising agents such as Bromine, Chlorine etc. interfere as they react in the same way
as Ozone.
Reagent
Set
DPD No. 1/No. 3
DPD No. 1
DPD No. 3
GLYCINE
26
Form of reagent/Quantity
Tablet / per 100
inclusive stirring rod
Tablet / 100
Tablet / 100
Tablet / 100
Order-No.
517711BT
511050BT
511080BT
512170BT
MD200_4 03/2018