Hach DR/700 Procedures Manual page 424

OXYGEN, DISSOLVED, HR,
4.
Fill a blue ampul
cap with sample. Fill
a 10-mL cell with
10 mL of sample.
Collect at least 40 mL
of sample in a 50-mL
beaker.
2 minutes
7.
Wait 2 minutes.
Note: A two-minute
reaction period enables
oxygen, which was
degassed during
aspiration, to redissolve
and react.
5.
Fill a High Range
Dissolved Oxygen
AccuVac Ampul with
sample (the prepared
sample).
Note: Keep the tip
immersed while the
ampul fills completely.
30 seconds
8.
At the end of the
two-minute period,
shake the ampul for
30 seconds.
52-98
continued
30 seconds
6.
Without inverting
the ampul,
immediately place the
ampul cap that was
filled with sample
securely over the tip
of the ampul. Shake
the ampul for
approximately 30
seconds.
Note: A small amount of
undissolved HRDO
Reagent does not affect
results.
Note: The cap prevents
contamination with
atmospheric oxygen.
9.
Place the blank in
the cell holder.
Note: In bright sunlight
it may be necessary to
close the cell
compartment cover.