GB
Methods
Remove the vial from the sample chamber.
Place the sample in the sample chamber making sure that the
marks are aligned.
Press the [ZERO/TEST] key.
The method symbol flashes for approx. 8 seconds.
The result is shown in the display in mg/l Fe.
Notes:
1. Rinse all glassware with detergent, followed by tap water. Rinse again with 1:1
Hydrochloric acid solution and deionized water. These steps will remove deposits that
can cause slightly high results.
2. Take the sample reading immediately after the instrument zero, If the sample contains
100 mg/l or more Molybdate (MoO
4
2-
).
3. For more accurate results, a reagent blank value for each new lot of reagent is advis-
able. Follow the described procedure using deionized water instead of the sample.
Subtract the obtained reading value from the final results.
4. Interference pH: A sample pH of less than 3 or more than 4 after addition of reagent,
may inhibit colour formation, as the developed colour fades too quickly or results in
turbidity. Adjust the sample pH to between 3 and 5 in the graduated cylinder before the
addition of reagent:
• Add by drops an applicable amount of Iron-free acid or base eg. 1 N Sulfuric acid
solution or 1 N Sodium hydroxide solution.
• If necessary make a volume correction if significant volumes of acid or base are used.
5. If Iron is present a blue colour developes. A small amount of undissolved reagent does
not have an affect on the results of the test.
Sample collection and storage:
• Collect samples in clean glass or plastic bottles. These should have been cleaned with 6
N (1:1) Hydrochloric acid and rinsed with deionised water.
• To preserve samples for later analysis, adjust the sample pH to less than 2 with concen-
trated Hydrochloric acid by adding about 2 ml per liter. If the sample is tested immedi-
ately this acid addition is not necessary.
• If the dissolved Iron is required, filter the sample through a 0.45-micron filter or equiva-
lent medium immediately after collection and before acidification.
• The preserved samples should be kept at room temperature for a maximum of 6
months.
• Adjust the pH to 3 – 5 by adding 5 N Sodium hydroxide solution before analysis. Do not
exceed pH 5 as Iron might precipitates.
• The test result needs to be corrected for the dilution caused by the volume additions.
Reagent Form of reagent/Quantity Order-No.
Set
VARIO (Fe in Mo) Rgt 1
VARIO (Fe in Mo) Rgt 2
Powder Pack / 100
Powder Pack / 100
536010
Zero
Test
RESULT
FE M
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