LaMotte SMART Spectro Spectrophotometer User Manual
Page 182
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 (4042) 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.
þNOTE: Invert slowly and completely for accurate results. Hold tubes
with caps up. Invert the tube and wait for the air bubble to flow 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 inversion.
22.
Wait 5 minutes.
SMART SPECTRO TEST PROCEDURES 05.04
Nitrogen, Total 3/4