LaMotte SMART 2 - Manual (Page 114)

PROCEDURE
1. Press and hold ON button until colorimeter turns on.
2. Press ENTER to start.
3. Press ENTER to select TESTING MENU.
4. Select ALL TESTS (or another sequence containing 22 Chromium)
from TESTING MENU.
5. Scroll to and select 22 Chromium from menu.
6. Rinse a clean tube (0290) with sample water. Fill to the 10 mL line with
sample.
7. Insert tube into chamber, close lid and select SCAN BLANK.
8. Remove tube from colorimeter. 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.
9. During waiting period, fold a piece of filter paper (0465) in half then half
again to form a cone. Push corners together to open end, and insert into
funnel (0459).
10. At the end of 3 minute waiting period, filter sample into a clean tube.
Mix. Insert tube into chamber, close lid and select SCAN SAMPLE.
Record result.
11. Press OFF button to turn colorimeter off or press
EXIT button to exit to a
previous menu or make another menu selection.
þ NOTES: To convert result to ppm chromate (CrO
42–
) 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 2/2 Smart2 TEST PROCEDURES 2.04