Hach DR/850, Procedures Manual, Page: 255 / 460

255
Method 10019
NITRITE, Low Range, Test ‘N Tube
(0–0.500 mg/L NO
2
- -N)
Diazotization Method
For water, wastewater, and seawater
USEPA approved for wastewater analysis
*
1.
Enter the stored
program number
for nitrite nitrogen
(NO
2
-
-N), Test ‘N Tube.
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:
63 ENTER
The display will show
mg/L, NO2-N and the
ZERO icon.
Note: For alternate forms
(NO
2
-
, NaNO
2
), press the
CONC key.
3.
Insert the COD/TNT
Adapter into the cell
holder by rotating the
adapter until it drops
into place. Then push
down to fully insert.
Note: For increased
performance, a diffuser
band covers the light path
holes on the adapter. Do
not remove the diffuser
band.
4.
Fill a Test ‘N Tube
NitriVer
®
3 Nitrite vial
with 5 mL of sample.
Cap and shake to
dissolve powder. This is
the prepared sample.
5.
Press:
TIMER ENTER
A 20-minute reaction
period will begin.
Note: A pink color will
develop if nitrite is present.
6.
When the timer
beeps, fill an empty
Test ‘N Tube vial with
5 mL of sample
(the blank).
7.
Clean the outside of
the vials with a towel.
Note: Wipe with a damp
towel and follow with a dry
one to remove fingerprints
and other marks.
8.
Place the blank in the
vial adapter.
Push straight down on
the top of the vial until it
seats solidly into the
adapter.
Note: Do not move the vial
from side to side as this can
cause errors.
* Federal Register, 44(85) 25505 (May 1, 1979).