Hach DR/850 Procedures Manual page 245

NITRATE, Low Range,
13.
Press:
READ
The cursor will move to
the right, then the result
-
in mg/L NO -N
3
(or alternate form) will
be displayed.
Note: Standard Adjust may
be performed using a
prepared standard
(see Section 1).
Note: Rinse the sample cell
and cylinder immediately
after use to remove all
cadmium particles.
Sampling and Storage
continued
Note: See Pollution
Prevention and Waste
Management for proper
disposal of cadmium.
Collect samples in clean plastic or glass bottles. Store at 4 °C (39
°F) or lower if the sample is to be analyzed within 24 to 48 hours.
Warm to room temperature before running the test. For longer
storage periods, adjust sample pH to 2 or less with sulfuric acid,
ACS (about 2 mL per liter). Sample refrigeration is still required.
Before testing the stored sample, warm to room temperature and
neutralize with 5.0 N Sodium Hydroxide Standard Solution. Do
not use mercury compounds as preservatives. Correct the test
result for volume additions; see Correction for Volume Additions
(Section 1) for
more information.
245