LaMotte SMART 2 - Manual (Page 90)

SAMPLE
HANDLING &
PRESERVATION: Chlorine in aqueous solutions is not stable, and the chlorine
content of samples or solutions, particularly weak solutions,
will rapidly decrease. Exposure to sunlight or agitation will
accelerate the reduction of chlorine present in such
solutions. For best results, start analysis immediately after
sampling. Samples to be analyzed for chlorine cannot be
preserved or stored.
INTERFERENCE: The only interfering substance likely to be encountered in
water is oxidized manganese. The extent of this interference
can be determined by treating a sample with sodium arsenite
to destroy the chlorine present so that the degree of
interference can be measured.
Iodine and bromine can give a positive interference, but
these are not normally present unless they have been added
as sanitizers.
Chlorine- Liquid DPD 2/3 Smart2 TEST PROCEDURES 2.04