Hach DR/850, Procedures Manual, Page: 329 / 460

329
Method 8316
OXYGEN, DISSOLVED, Low Range
(0 to 1000 µg/L O
2
) For boiler feedwater
Indigo Carmine Method
(Using AccuVac Ampuls)
1.
Enter the stored
program number for low
range dissolved oxygen
(O
2
).
Press:
PRGM
The display will show:
PRGM ?
Note: For most accurate
results, perform a Reagent
Blank Correction using
deionized water (see
Section 1).
2.
Press:
71 ENTER
The display will show
µg/L, O2 and the
ZERO icon .
3.
Fill a sample cell
with at least 10 mL of
sample (the blank).
Note: Samples must be
analyzed immediately and
cannot be stored.
4.
Place the blank into
the cell holder. Tightly
cover the sample cell
with the instrument cap.
5.
Press:
ZERO
The cursor will move to
the right, then the
display will show:
0 µg/L O2
Note: If Reagent Blank
Correction is on, the
display may flash “limit”.
See Section 1.
6.
Collect at least 40
mL of sample in a
50-mL beaker. Fill a
Low Range Dissolved
Oxygen AccuVac
Ampul with sample.
Note: Keep the tip
immersed while the ampul
fills completely.
7.
Immediately place
the AccuVac ampul into
the cell holder. Tightly
cover the ampul with the
instrument cap.
Note: The ampuls will
contain a small piece of
wire to maintain reagent
quality. The solution color
will be yellow.
8.
Press:
READ
The cursor will move to
the right, then the result
in µg/L dissolved
oxygen will be
displayed.
Note: Use the initial
reading. The reading is
stable for 30 seconds. After
30 seconds, the ampul
solution will absorb oxygen
from the air.