Hach DR/850, Procedures Manual, Page: 80 / 460

80
Sampling and Storage
Analyze samples for bromine immediately after collection.
Avoid plastic containers since these may have a large bromine
demand. Pretreat glass sample containers to remove any
bromine demand by soaking in a dilute bleach solution (1 mL
commercial bleach to l liter of deionized water) for at least 1
hour. Rinse thoroughly with deionized or distilled water. If
sample containers are rinsed thoroughly with deionized or
distilled water after use, only occasional pretreatment is
necessary.
A common error in testing for bromine is introduced when a
representative sample is not obtained. If sampling from a tap, let
the sample flow for at least 5 minutes to ensure a representative
sample. Let the container overflow with the sample several times,
then cap the sample container so there is no headspace (air) above
the sample. If sampling with a sample cell, rinse the cell several
times with the sample, then carefully fill to the 10-mL mark.
9.
After the timer beeps,
place the AccuVac
ampul into the cell
holder. Tightly cover the
ampule with the
instrument cap.
10.
Press:
READ
The cursor will move to
the right, then the result
in mg/L bromine will
be displayed.
Note: If the sample
temporarily turns yellow
after reagent addition, or
the display flashes “limit”,
it is due to high bromine
levels. Dilute a fresh sample
and repeat the test. A slight
loss of bromine may occur
during dilution. Multiply
the result by the dilution
factor; see Section 1.
Note: Standard Adjust may
be performed using a
prepared standard
(see Section 1).
BROMINE,
continued