LaMotte SMART3 Colorimeter - Manual (Page 141)

PROCEDURE
Use COD/UDV adapter.
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 3 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 and hold
until colorimeter turns on.
12. Press ENTER to select TESTING MENU.
13. Select ALL TESTS (or another sequence containing 024 COD LR) from
PROGRAMMED TESTS menu.
14. Scroll to and select 024 COD LR from menu.
15. Wipe the blank tube with a damp towel to remove fi ngerprints and smudges.
Wipe with a dry towel.
16. Insert reagent blank tube into chamber. Select SCAN BLANK.
17. Remove tube from colorimeter.
18. Insert digested water sample tube into chamber. Select SCAN SAMPLE.
Record result. For the most accurate results, take three readings on each
sample and average the results.
19. Press to turn colorimeter off or press
EXIT
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.
A reagent blank should be run with each set of samples and with each lot of
reagents.
The reacted blank will be stable if stored in the dark.
To eliminate error caused by contamination, wash all glassware with 20% sulfuric
SMART3 Test Procedures 11.10 COD, Low Range
Test P
rocedures