Hach DR/850 Procedures Manual page 238

NITRATE, High Range,
9.
Place the AccuVac
Ampul into the cell
holder. Tightly cover the
ampul with the
instrument cap.
Sampling and Storage
continued
10.
Press:
READ
The cursor will move to
the right, then the result
in mg/L NO -N (or
3
alternate form) will
be displayed.
Note: Use of the Standard
Adjust feature for each new
lot of reagent is highly
recommended. See Accuracy
Check.
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.
238