Thermo Scientific Orion AquaMate UV-Vis, Руководство пользователя

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Chapter 5
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Orion AQUAfast Reagent Chemistry Instructions for Orion AquaMate
Thermo Scientific Orion AquaMate Spectrophotometer User Manual | 55
ACR012 Ammonia Low Range Reaction Tube Test
Salicylate Method
0.02 – 2.5 mg/l N (Ammonia as Nitrogen)
1. Load and run the ACR012 method.
2. Open one 16 mm reaction vial and add 2 ml of deionized water (this is the blank vial).
3. Open a second 16 mm reaction vial and add 2 ml of sample (this is the sample vial).
4. Add the contents of one Ammonia Salicylate F5 Powder Pack straight from the foil into
each vial.
5. Add contents of one Ammonia Cyanurate F5 Powder Pack straight from the foil into each
vial.
6. Close the vials tightly with the caps and swirl or invert several times to mix the contents.
Wipe the exteriors of the vials.
7. Wait for a reaction period of 20 minutes.
8. Place the blank vial into the holder in the sample chamber and close the chamber door.
9. Press the Measure Blank function key to measure the blank.
10. Open the sample chamber door. Remove the blank vial from the holder.
11. Place the sample vial into the holder in the sample chamber and close the chamber door.
12. Press the Measure Sample function key to display the result in mg/l ammonia as N.
Notes:
• Strong alkaline or acidic water samples must be adjusted to approximately pH 7 before
analysis (use 1 mol/l hydrochloric acid or 1 mol/l sodium hydroxide).
• If chlorine is known to be present, add one drop of 0.1 mol/l sodium thiosulfate for each 0.3
mg/l Cl
2
in a one liter water sample.
• Iron interferes with the test. The interferences can be eliminated as follows: Determine the
amount of total iron present in the water sample. To produce the blank add an iron
standard solution with the same iron concentration to the vial instead of deionized water.
•
Conversion: mg/l NH
4
= mg/l N x 1.29
mg/l NH
3
= mg/l N x 1.22