Thermo Scientific AQUAfast AQ3700, User Manual

Page: 198 / 264

Thermo Scientific Orion AQUAfast AQ3700 Colorimeter User Guide
1.1 Methods
Urea
with Tablet and Liquid Reagent
0.1 – 3 mg/l (NH
2
)
2
CO / mg/l Urea
1. Fill a clean vial (24 mm Ø) with 10 ml of the water
sample
, close tightly with the cap.
2. Place the vial in the sample chamber making sure that
the marks are aligned.
3. Press ZERO key.
4. Remove the vial from the sample chamber.
5. Add
2 drops of Urea reagent 1
to the water sample
(Note 8).
6. Close the vial tightly with the cap and swirl several times
to mix the contents.
7. Add 1 drop of Urea Reagent 2 (Urease) to the same
water sample (Note 8).
8. Close the vial tightly with the cap and swirl several times
to mix the contents.
9. Press [ ] key.
Wait for a reaction period of 5 minutes .
After the reaction period is finished proceed as follows:
10. Add
one AMMONIA No. 1 tablet
straight from the
foil to the prepared water sample and mix to dissolve
with a clean stirring rod.
11. Add one AMMONIA No. 2 tablet straight from the
foil to the same water sample and mix to dissolve with
a clean stirring rod.
prepare Zero
press ZERO
Countdown
5:00
start:
9 0 3