Hach DR/700 Procedures Manual page 254

CYANURIC ACID,
10.
Press:
ZERO
The display will
count down to 0.
Then the display will
show the
concentration of the
standard and the zero
prompt will turn off.
SAMPLING AND STORAGE
Collect samples in clean plastic or glass bottles. Samples must be
analyzed within 24 hours.
CALIBRATION
A new calibration is necessary for each now manufacturing lot of
Cyanuric Acid 2 Reagent Powder Pillows. A new calibration is also
necessary when the water sample to be tested has a cyanuric acid
concentration which is not between that of the standards used to
calibrate the DR/700.
Perform the calibration as follows:
a) Dissolve 1.000 gram of cyanuric acid in l liter of demineralized water
to make a 1000-mg/L solution. Fill the flask half-full with
demineralized water, then agitate the flask until all the solid has
dissolved. Add demineralized water to the line. Cap and invert 10 times
to mix. This stock solution is stable for several weeks.
continued
11.
Place the
prepared sample in
the cell holder.
Note: Typical indoor
lighting permits the
DR/700 to operate with
the cell compartment
open. In bright
sunlight, it may be
necessary to close the
cell compartment cover.
Transfer 10 mL of the
blank and 10 mL of the
sample to a
10-mL sample cell and
proceed.
50-4
12.
Within 7
minutes after the
3-minute reaction
period, press:
READ
The display will
count down to 0.
Then the display will
show the results in
mg/L cyanuric acid.
Note: Clean sample
cells with soap, water
and a brush soon after
each test to prevent a
white film forming on
the cells.