LaMotte SMART Spectro Spectrophotometer - Manual (Page 117)

PROCEDURE
Use universal sample holder
1. Press and hold ON button until spectrophotometer turns on.
2. Scroll to and select PROGRAMMED TESTS.
3. Scroll to and select ALL TESTS (or another sequence containing
23 Chromium-TT) from TESTING MENU.
4. Scroll to and select 23 Chromium-TT from menu.
5. Rinse a tube (0290) with sample water. Fill to 10 mL with sample.
6. Insert the tube into chamber, close lid and select SCAN BLANK.
7. Remove the tube from Spectro.
8. Add one *Chromium Spectrophotometric Grade Tablet (3889).
9. Use Tablet Crusher (0175) to crush tablet.
10. Cap tube.
11. Shake vigorously for 30 seconds.
12. Wait 3 minutes.
13. Insert tube into chamber, close lid and select SCAN SAMPLE. Record result
in ppm chromium.
14. Press OFF button to turn the spectrophotometer off or press EXIT button to
exit to a previous menu or make another menu selection.
NOTES: For best possible results, a reagent blank should be determined to
account for any contribution to the test result by the reagent system. To determine
the reagent blank, follow the above test procedure to scan a distilled or deionized
water blank. Then follow the above procedure to perform the test on a distilled or
deionized water sample. This test result is the reagent blank. Subtract the reagent
blank from all subsequent test results of unknown samples.
To convert results to ppm chromate (CrO
4
-2 ), multiply by 2.23. To convert result to
ppm sodium chromate (Na
2
CrO
4
) multiply by 3.12.
CHROMIUM, TesTab SMART Spectro Test Procedures 2.11
Test P
rocedures