LaMotte SMART3 Colorimeter - Manual (Page 291)

PROCEDURE
A. PREPARATION OF DILUTE ZINC INDICATOR SOLUTION
1. Use a pipet (0352) to add exactly 5.0 mL of *Zinc Indicator Solution (6314)
to a 10 mL graduated cylinder (0416). The bottom of the curved surface (the
meniscus) of liquid should be at 5.0 mL mark. Pour this into the bottle labeled
“Dilute Zinc Indicator Solution” (6314-MT).
2. Use unrinsed graduated cylinder to add 10.0 mL and then 7.8 mL (total of 17.8
mL) of *Methyl Alcohol (6319) to bottle labeled “Dilute Zinc Indicator Solution”
(6314-MT). Cap and mix ingredients in this bottle. Do not leave this bottle
uncapped.
B. DETERMINATION OF ZINC
1. Press and hold until colorimeter turns on.
2. Press ENTER to select TESTING MENU.
3. Select ALL TESTS (or another sequence containing 099 Zinc LR) from
TESTING MENU.
4. Scroll to and select 099 Zinc LR 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. (See Note)
7. Remove tube from colorimeter. Use 0.1 g spoon (0699) to add one measure
of Sodium Ascorbate Powder (6316). Use 0.5 g spoon (0698) to add one
measure of *Zinc Buffer Powder (6315). Cap and shake vigorously for 1
minute. Some undissolved buffer may remain in the bottom of the tube.
8. Add 3 drops of *Sodium Cyanide, 10% (6565). Cap and mix.
9. Use the 1 mL pipet assembly to add 1 mL of “Dilute Zinc Indicator Solution”.
Cap and mix.
10. Use a second plain pipet (0352) to add 4 drops of *Formaldehyde Solution,
37% (5128). Cap and mix by inverting 15 times.
11. Insert tube into chamber, close lid and select SCAN SAMPLE. Record result.
12. Press
to turn colorimeter off or press
EXIT
to exit to a previous menu or
make another menu selection.
NOTE: 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. It is necessary to
determine the reagent blank only when a new lot number of reagents is obtained.
SMART3 Test Procedures 11.11 ZINC, Low Range
Test P
rocedures