LaMotte SMART Spectro Spectrophotometer - Manual (Page 99)

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 filter 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, filter 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.
þNOTES: 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 SMART SPECTRO TEST PROCEDURES 05.04