Hach DR/850 Procedures Manual page 156

CYANIDE,
continued
:30 seconds
5.
Press:
TIMER
ENTER
A 30-second reaction
period will begin. Shake
the sample cell for the
30 seconds.
9.
Add the contents of
one CyaniVer 5 Cyanide
Reagent Powder Pillow.
Cap the cell.
6.
After the first timer
beeps, the display will
show: 0:30 TIMER 2
Press
ENTER.
A 30-second reaction
period will begin. Let
the sample cell sit
undisturbed for this
30-second period.
10.
Shake vigorously
to completely dissolve
the CyaniVer 5 Cyanide
Reagent Powder (the
prepared sample).
7.
After the timer beeps,
add the contents of one
CyaniVer 4 Cyanide
Reagent Powder Pillow.
Cap the sample cell.
11.
The display will
show: 30:00 Timer 3
Press:
ENTER
A 30-minute reaction
period will begin.
Note: If cyanide is present,
a pink color will develop
which then turns blue after
a few minutes.
156
:10 seconds
8.
Shake the sample cell
for ten seconds.
Immediately proceed
with Step 9.
Note: Delaying the
addition of the CyaniVer 5
Cyanide Reagent Powder
for more than 30 seconds
after the addition of the
CyaniVer 4 Cyanide
Reagent Powder will give
lower test results.
Note: Accuracy is not
affected by undissolved
CyaniVer 4 Cyanide
Reagent Powder.
12.
Fill another 10-mL
sample cell (the blank)
with 10 mL of sample.