Lovibond MD200, Instruction Manual, Page: 43 / 160

43
MD200_8 07/2016
GB
Methods
Notes:
1. Vial cleaning:
As many household cleaners (e.g. dishwasher detergent) contain reducing substances,
the subsequent determination of Bromine may show lower results. To avoid any meas-
urement 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 Bromine, 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 22 mg/l Bromine can lead to results showing 0 mg/l. In this case,
the water sample must be diluted with water free of Chlorine and the measurement
repeated.
5. Oxidising agents such as Bromine, Ozone etc. interfere as they react in the same way as
Bromine.
Reagent Form of reagent/Quantity Order-No.
DPD No. 1 Tablet / 100 511050BT