Tintometer Lovibond MD100 Instrucciones página 51

Methods
GB
Notes:
1. Temperature of the sample should be 15°C –25°C.
2. If Silica or Phosphate is present a yellow colour is developed.
3. In this step any yellow colour due to Phosphate is removed.
4. Substances who may interfere when present in concentrations at:
Substance
Iron
Phosphate
Sulfide
Occasionally water samples contain forms of silica which reacts very slowly with Molyb-
date. The nature of these forms is not known.
A pre-treatment with Sodium hydrogencarbonate and then with Sulfuric Acid will make
these forms reactive to Molybdate (pre-treatment is given in "Standard Methods for the
Examination of Water and Wastewater" under "Silica Digestion with Sodium Bicarbo-
nate").
5. Conversion:
mg/l Si = mg/l SiO
2
Reagent
Set
VARIO Silica HR Molybdate F10
VARIO Silica HR Acid Rgt F10
VARIO Silica HR Citric Acid F10
MD100_2 10/2014
Interference
large amounts interfere
does not interfere at concentrations less than 50 mg/l PO
at 60 mg/l PO the interference is approx. – 2%
4
at 75 mg/l PO the interference is approx. – 11 %
4
interferes at all levels
x 0.47
Form of reagent/Quantity
Powder Pack / 100
Powder Pack / 100
Powder Pack / 100
4
Order-No.
535700
51