Chapter 5
|
Orion AQUAfast Reagent Chemistry Instructions for Orion AquaMate
92
|
Orion AquaMate Spectrophotometer User Manual
Thermo Scientific
ACD004 Nitrogen (Total) Low Range Digestion Tube Test
Persulfate Digestion Method
0.5 – 25 mg/l N (Nitrite as Nitrogen)
1.
Open two TN Hydroxide LR Digestion Vials and add the contents of one TN Persulfate
Reagent Power Pack straight from the foil into each vial. Use a funnel to add the reagent.
Wipe off any persulfate reagent that may get on the lid or tube threads.
2.
Add 2 ml of deionized water to the first digestion vial (this is the blank vial).
3.
Add 2 ml of sample to the second digestion vial (this is the sample vial).
4.
Close the vials tightly with the caps and shake the vials for at least 30 seconds to mix the
contents. The reagent many not dissolve completely.
5.
Heat the digestion vials for 30 minutes in the preheated reactor at a temperature of 100 °C.
6.
CAUTION: The vials will be hot. Remove the digestion vials from the reactor and allow
them to cool to room temperature.
7.
Open the cooled digestion vials and add the contents of one TN Reagent A Power Pack
straight from the foil into each vial. Use a funnel to add the reagent.
8.
Close the vials tightly with the caps and shake the vials for at least 15 seconds to mix
contents.
9.
Wait for a reaction period of 3 minutes.
10.
Open the digestion vials and add the contents of one TN Reagent B Power Pack straight
from the foil into each vial. Use a funnel to add the reagent.
11.
Close the vials tightly with the caps and shake the vials for at least 15 seconds to mix
contents. The reagent will not completely dissolve.
12.
Wait for a reaction period of 2 minutes.
13.
Open two TN Acid LR/HR (Reagent C) Vials and add 2 ml of the digested, treated blank to
the first vial (this is the blank vial).
14.
Add 2 ml of the digested, treated sample to the second vial (this is the sample vial).
15.
Close the vials tightly with the caps and gently invert the vials at least 10 times to mix
contents. 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. Return the vial to the upright
position. Wait for all the solution to flow to the bottom of the vial. This process is one
inversion; 10 inversions equal about 30 seconds. Wipe the exteriors of the vials.
CAUTION: The vials will become warm during mixing.
16.
Wait for a reaction period of 5 minutes.
17.
Load and run the ACD004 method.
18.
Place the blank vial into the holder in the sample chamber and close the chamber door.