Test Procedures
PROCEDURE
Use universal sample holder
1. Preheat COD reactor to 100 ±2°C. Follow safety precautions.
2. Remove caps from two *Total Nitrogen Hydroxide Reagent Tubes (4040).
3. Use a 0.15 g spoon (0727) and a funnel (0459) to add one level measure of *Digestion
Reagent Powder (4036) to each tube. Tap funnel to dispense powder completely.
4. Use a 1.0 mL pipet (0354) to add 2.0 mL of Deionized Water (5115PS), or organic-free
water, to one tube. This is the blank.
5. Use another 1.0 mL pipet (0354) to add 2.0 mL of sample to the other tube. This is the
sample.
6. Cap both tubes and shake vigorously for 30 seconds.
7.
Place the tubes in the COD reactor for 30 minutes.
8. After exactly 30 minutes, turn the reactor off . Carefully remove the tubes from the
reactor and allow them to cool to room temperature.
9. At the end of the cooling period, press
ON
button to turn spectrophotometer on.
10. Scroll to and select
PROGRAMMED TESTS
from the menu.
11. Scroll to and select
ALL TESTS
(or another sequence containing
62 Nitrogen T
) from
PROGRAMMED TESTS
menu.
12. Scroll to and select
62 Nitrogen T
from the menu.
13. Carefully remove caps from the digested tubes.
14. Use a 0.15 g spoon (0727) and a funnel (0459) to add one level measure of *Total
Nitrogen Reagent A Powder (4041). Tap funnel to dispense powder completely. Cap
the tubes and shake for 15 seconds.
15. Wait 3 minutes.
16. Remove the caps from the tubes. Add one *Total Nitrogen Reagent B Tablet
(4042A) to each tube. Cap the tubes and shake for 45 seconds or until the tablet
disintegrates.
17. Wait 2 minutes.
18. Remove the caps from the reacted tubes. Carefully remove the caps from two *Total
Nitrogen Acid Reagent Tubes (4043). CAUTION: Tubes contain a strong acid.
19. Use another 1.0 mL pipet (0354) to add 2 mL of digested, treated blank to one Total
Nitrogen Acid Reagent Tube. This is the blank.
20. Use another 1.0 mL pipet (0354) to add 2 mL of digested, treated sample to the other
Total Nitrogen Acid Reagent Tube. This is the sample.
21. Cap the tubes and invert 10 times to mix. CAUTION: The tubes will be hot.
NOTE: Invert slowly and completely for accurate results. Hold tubes with caps up.
Invert the tube and wait for the air bubble to fl ow to the bottom of the tube. Turn the
tube upright and wait for the air bubble to return to the top of the tube. This is one
SMART Spectro 2 Test Procedures 05.02.16
NITROGEN
, TOTAL
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