LaMotte SMART Spectro Spectrophotometer - Manual (Page 241)

APPLICATION: Boiler and cooling waters; domestic and industrial
wastes.
RANGE: 0–50 ppm Silica
MDL: 1 ppm
METHOD: Silica forms a complex with ammonium molybdate in an
acidic solution to produce a yellow color in proportion to
the amount of silica present. Phosphate also reacts with
molybdate but the addition of oxalic acid eliminates the
molybdophosphoric acid complex.
SAMPLE HANDLING
& PRESERVATION:
Silica samples may be preserved by refrigeration at 4°C
in plastic containers up to one week without any change
in silica concentration.
INTERFERENCES: Sulfi des and large amounts of iron interfere. Color
and turbidity may be removed by standardizing the
instrument with the original water sample.
SILICA, High Range SMART Spectro Test Procedures 2.11
Test P
rocedures