LaMotte SMART Spectro Spectrophotometer - Manual (Page 126)

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. Hold tube 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 tube.
4. Cap and mix thoroughly.
5. Rinse the outside of the tube with distilled water. Wipe dry with a paper
towel.
6. Repeat steps 2 through 5 using 2.0 mL distilled water. This is the reagent
blank.
7. Place tubes 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
tubes to cool to 120°C or less.
9. Remove tubes 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 26 COD
SR 0-1500) from PROGRAMMED TESTS menu.
14. Wipe the blank tube with a damp towel to remove fi ngerprints and smudges.
Wipe with a dry towel.
15. Scroll to and select 26 COD SR 0-1500 from menu.
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.
NOTES: Reagents are light sensitive. Unused reagents should be stored in the
shipping container, and in the refrigerator if possible, until needed.
SMART Spectro Test Procedures 2.11 COD, Standard Range
Test P
rocedures