LaMotte SMART Spectro Spectrophotometer - Manual (Page 111)

PROCEDURE
Use universal sample holder.
1. Press and hold ON button until spectrophotometer turns on.
2. Scroll to and select PROGRAMMED TESTS from menu.
3. Scroll to and select ALL TESTS (or another sequence containing
22 Chromium) from TESTING MENU.
4. Scroll to and select 22 Chromium from menu.
5. Rinse a clean tube (0290) with sample water. Fill to the 10 mL line with
sample.
6. Insert tube into chamber, close lid and select SCAN BLANK.
7. Remove tube from Spectro. Use the 0.1g spoon (0699) to add one measure of
*Chromium Reagent Powder (V-6276). Cap and shake until powder dissolves.
Wait 3 minutes for full color development.
8. During waiting period, fold a piece of fi lter paper (0465) in half then half again
to form a cone. Push corners together to open end, and insert into funnel
(0459).
9. At the end of 3 minute waiting period, fi lter sample into a clean tube. Mix. Insert
tube into chamber, close lid and select SCAN SAMPLE. Record result.
10. Press OFF button to turn spectrophotometer off or press EXIT button to exit to
a previous menu or make another menu selection.
NOTES: To convert result 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.
Highly buffered waters may give poor results and require a more careful pH
adjustment. Before adding *Chromium Reagent Powder, adjust pH of sample to
pH 3-4.
CHROMIUM, Hexavalent SMART Spectro Test Procedures 2.11
Test P
rocedures