LaMotte CHROMIUM TEST KIT LSCV User Manual
Page 3
TOTAL CHROMIUM
1.
Use the graduated cylinder (0418) to measure 50 mL of sample water.
Pour into the Erlenmeyer flask (0431).
2.
Use the 1 mL pipet to carefully add 5 mL (5 x 1 mL) of *Sulfuric
Acid, 5N (7681).
NOTE:
Highly buffered waters may require more careful pH
adjustment.
3.
Place flask on burner or hot plate. Bring solution to a gentle boil.
4.
To the boiling solution, add Potassium Permanganate, 0.5% (7682),
one drop at a time, until the pink color persists for ten minutes.
5.
After boiling, add *Sodium Azide, 5% (7683), one drop at a time,
until pink color disappears.
6.
Cool sample under running tap water. Dilute to 50 mL line with
Deionized Water (5115PS).
7.
Fill test tube (0230) to 5 mL line with treated sample.
8.
Use the 0.05 g spoon (0696) to add one level measure *Chromium
Reagent Powder (V-6276). Cap and shake for one minute. Wait five
minutes.
9.
Insert test tube into Chromium Comparator (7679). Match sample
color to a color standard.
Record as ppm Chromium (Cr
+6
and Cr
+3
).
TRIVALENT CHROMIUM
Subtract Hexavalent Chromium from Total Chromium. Record as ppm
Trivalent Chromium (Cr
+3
).
Cr
+3
= Total Chromium - Cr
+6