Hach DR/850 Procedures Manual page 166

CYANURIC ACID,
9.
Place the prepared
sample into the cell
holder. Tightly cover
the sample cell with the
instrument cap.
Sampling and Storage
Accuracy Check
Method Performance
continued
10.
Press:
READ
The cursor will move to
the right, then the result
in mg/L cyanuric acid
will be displayed.
Note: Standard Adjust may
be performed using a
prepared standard
(see Section 1).
Note: Clean sample cells
with soap, water and a
brush soon after each test
to prevent a white film
from forming.
Collect samples in clean plastic or glass bottles. Samples must be
analyzed within 24 hours.
Standard Solution Method
a) Dissolve 1.000 gram of cyanuric acid in 1000 mL of
deionized water to make a 1000 mg/L solution. It takes
several hours for the cyanuric acid to dissolve. This
solution is stable for several weeks.
b) Dilute 2.00 mL of the 1000 mg/L solution to 100 mL with
deionized water to make a 20 mg/L solution. Prepare
fresh daily.
c) Testing the 20 mg/L solution should give test results of
about 20 mg/L cyanuric acid.
Precision
In a single laboratory, using a standard solution of 25.0 mg/L
cyanuric acid and two lots of reagent with the instrument, a single
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