Hach Ultra POLYMETRON 9210, Руководство оператора, Страница: 29 / 116

Page 23
SILKOSTAT 9210
4. Starting-up
Reagent preparation
Danger :
Read the precaution and security appendix and wear protective
goggles and clothes before use chemical products.
Reagent concentrations (by type)
Reagent 1 - Molybdate reagent
•
Sodium dihydrate molybdate 50 g/L
•
Concentrated sulphuric acid 45 mL/L
Reagent 2 - Oxalic reagent
•
Oxalic acid dihydrate 40 g/L
Reagent 3 - Reducing reagent
•
Concentrated sulphuric acid 12.5 mL/L
•
Ammonium ferrous ( II ) sulphate hexahydrate 20 g/L
Reagent preparation (makes 2 litres)
Reagent 1 - Molybdate reagent
Sodium dihydrate molybdate, Na
2
MoO
4
.2H
2
O, >99%, neat (analytical quality)
(FLUKA# 71756, MERCK# 106521 or equivalent)
100 g
Concentrated sulphuric acid, H
2
SO
4
, 95-97%, neat (analytical quality)
(FLUKA# 84721, MERCK# 100731 or equivalent)
90 mL
1) Fill a 2-litre graduated flask to 2/3rds capacity with demineralised water (with the lowest
possible silica content). Add the sodium dihydrate molybdate whilst stirring the solution.
2) Continue to stir until the molybdate is completely dissolved (<5minutes).
3) Still stirring, slowly add the concentrated sulphuric acid in 3 or 4 parts (measured out from
a test tube).
4) Keep stirring until completely dissolved (<5minutes).
5) Make up the volume to the gauge line (2 litres).
6) Leave to cool before transferring to the 2-litre container provided for this reagent.