Annexes
3.4. Silicium
REAGENTS
Remark: All reagents and standards must be prepared in polyethylene and stored in polyethylene bottles.
A. Sulfuric acid solution (1 liter)
Required chemicals: Sulfuric acid ................. 5 ml.
H2SO4 (95‐97%)
Distilled water
H2O
Lauryl sulfate ................... 1 g.
B. Ammonium heptamolybdate solution (1 liter)
Required chemicals: Ammonium
heptamolybdate ............ 10 g.
(NH4)6Mo7O24.4H2O
Distilled water
H2O
C. Oxalic acid solution (1 liter)
Required chemicals: Oxalic acid ..................... 44 g.
C2H2O4.2H2O
Distilled water
H2O
D. L(+)Ascorbic acid solution (1 liter)
Required chemicals: L(+)Ascorbic acid .......... 40 g.
C6H8O6
Distilled water
H2O
E. Rinsing liquid sampler
Required chemicals: Distilled water
H2O
STANDARDS
Stock solution 100 mg Si/liter (1 liter)
Required chemicals: Sodium
metasilicate ............ 1.0119 g.
Na2SiO3.9H2O
Distilled water
H2O
Preparation: Dilute the sulfuric acid in ± 800 ml
distilled water. Fill up to 1 liter with distilled water,
add the lauryl sulfate and mix.
Note: Solution is stable for 1 week. Store at 4°C
when the solution is not used.
Preparation:
Dissolve
the
ammonium
heptamolybdate in ± 800 ml distilled water. Fill up
to 1 liter with distilled water and mix.
Note: Solution is stable for 1 day. Do not use metal
spoons for the ammonium
heptamolybdate.
Preparation: Dissolve the oxalic acid in ± 800 ml
distilled water. Fill up to 1 liter with distilled water
and mix.
Note: Solution is stable for 1 month. Store at 4°C
when the solution is not used.
Preparation: Dissolve the L(+)ascorbic acid in ±
800 ml distilled water. Fill up to 1 liter with
distilled water and mix.
Note: Solution is stable for 1 week. Store at 4°C
when the solution is not used.
Note: For sea water samples, adjust the salinity of
the rinsing water sampler to the same level as the
salinity of the sea water samples when matrix peaks
reach the same level as the detection limit. Use ultra
pure sodium chloride or “zero” seawater for
adjustment. Refresh weekly.
Preparation: Dissolve the sodium metasilicate in ±
800 ml distilled water. Fill up to 1 liter with
distilled water and mix.
Note: Solution is stable for 1 month.
3.4. Silicium
REAGENTS
Remark: All reagents and standards must be prepared in polyethylene and stored in polyethylene bottles.
A. Sulfuric acid solution (1 liter)
Required chemicals: Sulfuric acid ................. 5 ml.
H2SO4 (95‐97%)
Distilled water
H2O
Lauryl sulfate ................... 1 g.
B. Ammonium heptamolybdate solution (1 liter)
Required chemicals: Ammonium
heptamolybdate ............ 10 g.
(NH4)6Mo7O24.4H2O
Distilled water
H2O
C. Oxalic acid solution (1 liter)
Required chemicals: Oxalic acid ..................... 44 g.
C2H2O4.2H2O
Distilled water
H2O
D. L(+)Ascorbic acid solution (1 liter)
Required chemicals: L(+)Ascorbic acid .......... 40 g.
C6H8O6
Distilled water
H2O
E. Rinsing liquid sampler
Required chemicals: Distilled water
H2O
STANDARDS
Stock solution 100 mg Si/liter (1 liter)
Required chemicals: Sodium
metasilicate ............ 1.0119 g.
Na2SiO3.9H2O
Distilled water
H2O
Preparation: Dilute the sulfuric acid in ± 800 ml
distilled water. Fill up to 1 liter with distilled water,
add the lauryl sulfate and mix.
Note: Solution is stable for 1 week. Store at 4°C
when the solution is not used.
Preparation:
Dissolve
the
ammonium
heptamolybdate in ± 800 ml distilled water. Fill up
to 1 liter with distilled water and mix.
Note: Solution is stable for 1 day. Do not use metal
spoons for the ammonium
heptamolybdate.
Preparation: Dissolve the oxalic acid in ± 800 ml
distilled water. Fill up to 1 liter with distilled water
and mix.
Note: Solution is stable for 1 month. Store at 4°C
when the solution is not used.
Preparation: Dissolve the L(+)ascorbic acid in ±
800 ml distilled water. Fill up to 1 liter with
distilled water and mix.
Note: Solution is stable for 1 week. Store at 4°C
when the solution is not used.
Note: For sea water samples, adjust the salinity of
the rinsing water sampler to the same level as the
salinity of the sea water samples when matrix peaks
reach the same level as the detection limit. Use ultra
pure sodium chloride or “zero” seawater for
adjustment. Refresh weekly.
Preparation: Dissolve the sodium metasilicate in ±
800 ml distilled water. Fill up to 1 liter with
distilled water and mix.
Note: Solution is stable for 1 month.