Thermo Scientific AQUAfast AQ3700, User Manual

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2 Thermo Scientific Orion AQUAfast AQ3700 Colorimeter User Guide
1.1 Methods
Nitrogen, total LR
with Digestion Tube Test
0.5 – 25 mg/l N
Insert the adapter for 16 mm Ø vials.
1. Open two TN Hydroxide LR digestion vials and add
the contents of one TN Persulfate Rgt. Powder
Pack (Note 2, 3).
2. Add 2 ml deionized water to the prepared vial (this is
the blank, Note 4, 5).
3. Add
2 ml of the water sample
to the other prepared vial
(this is the sample).
4. Close the vials with the caps and shake to mix the
contents (at least 30 seconds, Note 6).
5. Heat the vials for 30 minutes in the preheated reactor
at a temperature of
100°C
(Note 7).
6. After 30 minutes remove the vials from the reactor.
(CAUTION: The vials are hot!)
Allow the vials to cool to room temperature.
7. Open the cooled digestion vials and add the contents of one
TN Reagent A Powder Pack to each vial (Note 2).
8. Close the vials with the caps and shake to mix the
contents (at least 15 seconds).
9. Press
[ ]
key.
Wait for a
reaction period of 3 minutes.
After the reaction period is finished proceed as follows:
10. Open the digestion vials and add the contents of one
TN Reagent B Powder Pack to each vial (Note 2).
11. Close the vials with the caps and shake to mix the
contents (at least 15 seconds, Note 8).
12. Press
[ ]
key.
Wait for a reaction period of 2 minutes .
After the reaction period is finished proceed as follows:
13. Open
two TN Acid LR/HR (Reagent C) vials
and
add
2 ml of the digested, treated blank
to one vial
(this is the blank).
14. Add
2 ml of the digested, treated water sample
to
the other TN Acid LR/HR vial (this is the sample).
15. Close the vials with the caps and swirl the vials gently
several times to mix the contents (10 x, Note 9).
(CAUTION: Vials warm up).
Countdown
3:00
start:
Countdown
2:00
start:
1 2
3 4
Ø 16 mm
8 0 2