Hach DR/700 - Page 540

57-34
QUATERNARY AMMONIUM COMPOUNDS, continued
7. Fill a 25-mL cell
to the 25-mL line
with sample.
8. Add the contents
of one Q.A.C. Reagent
1 powder pillow. Cap
and invert to mix.
Remove cap after
mixing.
Note: Shaking the cell
will cause air bubble
turbidity which
dissipates slowly and
interferes with test
results.
9. Add the contents
of one Q.A.C.
Reagent 2 powder
pillow. Cap and
invert to mix.
10. Wait 2 minutes. 11. Place the blank in
the cell holder.
Note: Typical indoor
lighting permits the
DR/700 to operate with
the cell compartment
cover open. In bright
sunlight it may be
necessary to close the
cell compartment cover.
Transfer 10 mL of the
blank solution to a
10-mL cell. If the 10-mL
cell is used for the blank,
another 10-mL cell must
be used for the sample.
12. Press: ZERO
The display will
count down to 0.
Then the display will
show 0.0 mg/L and
the zero prompt will
turn off.
2 minutes