Hach DR2400 - Page 716

Silica
Silica
Page 2 of 6
Silica_PT_ULow_HTB_Eng_Ody.fm
5. Fill two clean 250-mL
Erlenmeyer flasks to
overflowing with sample.
6. Fill a clean 50-mL
plastic graduated
cylinder with sample
from one of the flasks;
then discard the contents
of the cylinder.
Repeat three times.
7. Fill the rinsed
cylinder to the 50-mL
mark with sample from
the same flask.
Discard any remaining
sample in the flask.
8. Pour the contents of
the 50-mL cylinder back
into the original flask.
9. Repeat step 6 through
step 8 for the second flask
containing sample.
10. Use a TenSette
®
Pipet
to add 1.0 mL of
Molybdate 3 Reagent to
each flask. Swirl to mix.
11. Touch the timer icon.
Touch
OK.
A four-minute reaction
period will begin.
12. When the timer
beeps, add 1.0 mL of
Citric Acid F Reagent to
each flask. Swirl to mix.
13. Touch the timer icon.
Touch
OK.
A one-minute reaction
period will begin. The
destruction of possible
phosphate interference
occurs during this period.
14. When the timer
beeps, pour the contents
of one flask into the
Pour-Thru Cell.
15. After the flow stops,
touch
Zero.
The display will show:
0 µg/L SiO
2
16. Add 1.0 mL of Amino
Acid F Reagent to the
remaining flask. Swirl to
mix.
A faint blue color will
develop if silica is present.
Repeat
Steps 6—8
Zero