LaMotte SMART Spectro Spectrophotometer - Manual (Page 108)

PROCEDURE
Use universal sample holder
1. Homogenize sample if necessary.
2. Preheat COD heater block to 150±2°C.
3. Remove cap from COD tube vial. Hold vial at a 45° angle. Use a
volumetric pipet, to carefully add 2.0 mL sample water allowing the sample
to run down the side of the vial.
4. Cap and mix thoroughly.
5. Rinse the outside of the vial with distilled water. Wipe dry with a paper
towel.
6. Repeat steps 3 through 5 using 2.0 mL distilled water. This is the reagent
blank.
7. Place vials in preheated COD block heater and maintain temperature at
150±2°C for two hours.
8. At the end of the heating period turn the heater off. Wait 20 minutes for
the vials to cool to 120°C or less.
9. Remove vials from block heater. Invert several times to mix.
10. Allow to cool to room temperature.
11. Press
ON
button until spectrophotometer turns on.
12. Scroll to and select PROGRAMMED TESTS from menu.
13. Scroll to and select ALL TESTS (or another sequence containing 25
COD LR 0-150
) from PROGRAMMED TESTS menu.
14. Scroll to and select 25 COD LR 0-150 from menu.
15. Wipe the blank vial with a damp towel to remove fingerprints and
smudges. Wipe with a dry towel.
16. Insert reagent blank tube into chamber. Align the center of the LaMotte
logo on the tube with the arrow shaped mark molded into the housing at
the front edge of the light chamber. Select SCAN BLANK.
17. Remove tube from Spectro.
18. Insert digested water sample tube into chamber. Position tube as instructed
above. Select SCAN SAMPLE. Record result. For the most accurate results,
take three readings on each sample and average the results.
19. Press
OFF
button to turn spectrophotometer off or press
EXIT
button to
exit to a previous menu or make another menu selection.
SMART SPECTRO TEST PROCEDURES 03.05 COD–LR 3/4