LaMotte 1200 Colorimeter - Manual (Page 52)

FLUORIDE SPADNS TEST METHOD SPECIFICATIONS
APPLICATION
Drinking and surface waters; domestic and industrial waters.
RANGE
0.0 to 2.0 ppm Fluoride
METHOD
Colorimetric test based upon the reaction between fluoride and zirconium dye lake. The
fluoride reacts with the dye lake, dissociating a portion of it into a colorless complex ion
and dye. As the fluoride concentration increases, the color produced becomes
progressively lighter.
HANDLING & PRESERVATION
Samples may be stored and refrigerated in plastic containers.
INTERFERENCES
The following substances produce a positive interference at the concentration given:
Chloride (Cl - ) 7000 mg/L
Phosphate (PO
4
-3 ) 16 mg/L
Hexametaphosphate (NaPO
3
)
6
1 mg/L
The following substances produce a negative interference at the concentration given:
Alkalinity (CaCO
3
) 5000 mg/L
Aluminum (Al +3 ) 0.1 mg/L
Iron (Fe +3 ) 10 mg/L
Sulfate (SO
4
-2 ) 200 mg/L
Color and turbidity must be removed or compensated for in the procedure. Temperature
should be maintained within 5 degrees Celcius of room temperature.
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