DR/2400
Nitrogen, Total
NitrogenTot_TNT_High_PSD_Eng_Ody.fm Page 1 of 6
• Digestion is required for determining total nitrogen. The digestion procedure is included below.
• Place a safety shield in front of the COD reactor to prevent injury if splattering occurs.
• This test is technique-sensitive. Invert the vials as described here to avoid low results: Hold the vial in a vertical position with the
cap pointing up. Turn the vial upside-down. Wait for all of the solution to flow down to the cap. Pause. Return the vial to an upright
position. Wait for all the solution to flow to the bottom of the vial. This process equals one inversion.
• Wipe the outside of sample cells before each insertion into the instrument cell holder. Use a damp towel followed by a dry one to
remove fingerprints or other marks.
• If the test overranges, repeat the digestion and measurement with diluted sample. The digestion must be repeated for
accurate results.
• Use the deionized water provided in the reagent set or Organic-free Water (Cat. No. 26415-49) to prepare the standards and
perform the procedure.
Nitrogen, Total
Method 10072
Persulfate Digestion Method
Test ‘N Tube™ Vials
HR (10 to 150 mg/L N)
Scope and Application: For water and wastewater.
1. Turn on the COD
Reactor. Heat to
103–106 °C.
2. Using a funnel, add
the contents of one Total
Nitrogen Persulfate
Reagent Powder Pillow
to each of two HR Total
Nitrogen Hydroxide
Digestion Reagent vials.
Wipe off any reagent that
may get on the lid or the
tube threads.
3. Add 0.5 mL of sample
to a vial (this is the
prepared sample).
Add 0.5 mL of the
deionized water included
in the kit to a second vial
(this is the reagent blank).
Note: Use only water that is
free of all nitrogen-containing
species as a substitute for the
deionized water provided.
4. Cap both vials. Shake
vigorously for at least
30 seconds to mix.
Note: The persulfate reagent
may not dissolve completely
after shaking. This will not
affect accuracy.
Tips and Techniques
Test ‘N Tube Method 10072
To Next Page
Loading...
