LaMotte 1200 Colorimeter - Manual (Page 43)

DPD BROMINE
TEST METHOD SPECIFICATIONS
APPLICATION
Drinking, surface, saline waters; swimming pool water; domestic and industrial waters
and wastes.
RANGE
0 to 7.0 mg/L Bromine (may be extended by dilution)
METHOD
In buffered sample, bromine reacts with disthyl-p-phenylene diamine (DPD) to produce
a pink-red color in proportion to the concentration of bromine present.
HANDLING & PRESERVATION
Bromine is aqueous solutions is not stable, and the bromine content of samples or
solutions, particularily weak solutions, will rapidly decrease. Exposure to sunlight or
agitation will acceslerater the reduction of bromine present in such solutions. For best
results, start analysis immediately after sampling. Samples to be analyzed for bromine
cannot be preserved or stored.
INTERFERENCES
The only interfering substance likely to be encountered in water is oxidized manganese.
The extent of this interference can be dtermined by treating a sample with sodium
arsenite to destroy the bromine present so that the degree of interference can be
estimated.
Iodine and chlorine can also interfere, but these are not normally present unless they
have been added as sanitizers.