Methods
GB
F
0.0.0
Zero
Test
F
RESULT
Notes:
1. The same batch of SPADNS reagent solution must be used for adjustment and test.
The adjustment process
performed for each new batch of SPANDS reagent solution (see Standard Methods 20th,
1998, APHA, AWWA, WEF 4500 F D., S. 4-82).
2. During adjustment and test the same vial should be used for zeroing and test, as differ-
ent vials may exhibit minor tolerances.
3. The calibration solution and the water samples to be tested should have the same tem-
perature (± 1°C).
4. As the test result is highly dependent on exact sample and reagent volumes, the sample
and reagent volumes should always be metered by using a 10 ml resp. 2 ml volumetric
pipette (class A).
5. The accuracy of the test methods decreases above a level of 1.4 mg/l Fluoride. Although
the results are sufficiently accurate for most applications, even more exact results can be
achieved by 1:1 dilution of the sample prior to use and subsequent multiplication of the
result by 2.
6. SPADNS reagent solution contains Arsenite.
Chlorine concentrations up to 5 mg/l do not interfere.
7. Sea- and wastewater samples must be distilled.
Reagent
SPADNS reagent solution
Fluoride standard
22
Fluoride with liquid reagent
0.05 – 2.0 mg/l F
Fill a clean vial (24 mm Ø) with 10 ml of the water sample and
perform zero calibration (see "Operation").
Add exactly 2 ml SPADNS reagent solution (Note 4) to the water
sample.
Caution: Vial is filled to the top!
Close the vial tightly with the cap and invert several times to mix the
contents.
Place the vial in the sample chamber making sure that the
are aligned.
Press the [ZERO/TEST] key.
The method symbol flashes for approx. 3 seconds.
The result is shown in the display in mg/l Fluoride.
Tolerances:
± 5 % (full scale, Note 5)
(see
"menu-options"
Form of reagent/Quantity
Liquid reagent / 250 ml
Solution / 30 ml
-
4
calibration mode Fluoride)
marks
needs to be
Order-No.
467481
205630
MD100_8 07/2016