Lovibond Tintometer MD 100 Manual De Instrucciones página 21

Silicate HR PP / M352
Analyses
The following table identifies the output values can be converted into other citation forms.
Unit
mg/l
mg/l
EN
Chemical Method
Silicomolybdate
Appendix
Interferences
Removeable Interferences
• Occasionally water samples contain forms of silica which reacts very slowly with
Molybdate. The nature of these forms is not known. A pre-treatment with Sodium
hydrogencarbonate and then with Sulphuric 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
Bicarbonate").
• If silicon dioxide or phosphate are present, a yellow colour develops.
The yellow colour caused by phosphate is eliminated by the addition of silica citric
acid F10 powder packets.
Interference
Fe
PO
3-
4
PO
3-
4
PO
3-
4
S
2-
22
Cite form
SiO
2
Si
from / [mg/l] Influence
large quantities
50
60 The disturbance is about -2 %
75 The disturbance is about -11 %
in all quantities
Scale Factor
1
0.47
EN Method Reference Book 1.0