22
METHOD PROCEDURE
• Press
Start.
The display will show a 25 minute countdown prior to the measurement.
To skip the timer, press
Read.
When the timer ends the meter will perform the reading.
The instrument displays concentration in
mg/L
of
cyanide (CN-)
.
Note:
Shake vigorously the cuvette 4 or 5 times during the first 20 minutes of the
timer. Accuracy is not affected by undissolved reagent powder.
• Press the
key and use the functional keys to select
Chemical Form
.
• Use the functional keys and press
Select
to change the displayed chemical formula
to
mg/L
of
potassium cyanide (KCN)
.
Note:
For accurate results perform the test at 20—25
°
C.
INTERFERENCES
Interference may be caused by:
• large amounts of turbidity that will cause high readings
Oxidizing (such as chlorine) or reducing agents (such as sulfide or sulfur dioxide) are
known to interfere with the measurement. Distillation will remove these.
Samples with high pH values should be adjusted to approximately pH 7 before testing.
CAUTION:
Cyanides, their solutions, and hydrogen cyanide liberated by acids, are
very poisonous.