LaMotte SMART Spectro Spectrophotometer - Manual (Page 202)

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 until spectrophotometer
turns 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.
SMART Spectro Test Procedures 10.12 NITROGEN, Total
Test P
rocedures