LaMotte DPC-52 Water Testing Laboratory - Manual (Page 7)

BROMINE
Like chlorine, this member of the halogen family is an effective germicidal agent. It is
sometimes used in place of chlorine for pool water disinfection. The desired level for
bromine in pool water is 2.0 - 4.0 ppm.
RANGE:
0.22 - 10 ppm
METHOD:
Bromine reacts with buffered diethyl-p-phenylene diamine
(DPD) to produce a pink-red color in proportion to the
concentration of bromine present.
INTERFERENCE:
The only interfering substance likely to be encountered in pool
water is oxidized manganese. The extent of this interference
can be determined by treating a sample with sodium arsenite
to destroy the bromine present, so that the amount of
interference can be measured.
PROCEDURE
1. Fill the water sample bottle (0688) with the pool water sample.
2. Dispense the water sample into a clean colorimeter tube (0967), until the tube is
filled to the 10 mL line.
3. Insert the tube containing the untreated sample into the colorimeter chamber, and
press the “Bromine” button. When the display reads “Blank 0.0,” press the
“Bromine” button again. Remove tube.
4. Add 5 drops of DPD 1A Free Chlorine Reagent (P-6740) and 5 drops of *DPD 1B
Free Chlorine Reagent (P-6741).
5. Cap and mix. The development of a pink color indicates the presence of Bromine.
6. Insert the treated sample into the colorimeter chamber. As soon as the display
stabilizes, read result in ppm Bromine.
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