Hach DR/700 Procedures Manual page 579

CYANIDE,
to 0.3 SCFH. If the contents of the distillation flask begin to back up
through the thistle tube, increase the air flow by adjusting the flow meter
until the contents do not back up through the thistle tube. Allow the
sample to boil for one hour.
l) When one hour is up, turn the still off but maintain the air flow for 15
minutes.
m) After 15 minutes, remove the rubber stopper on the 500-mL vacuum
flask to break the vacuum and turn off the water to the aspirator. Turn
off the water to the condenser.
n) Remove the gas bubbler/cylinder assembly from the distillation
apparatus. Separate the gas bubbler from the cylinder and pour the
contents of the cylinder into a 250-mL, Class A volumetric flask. Rinse
the gas bubbler, cylinder and J-tube connector with demineralized water
and add the washings to the volumetric flask.
o) Fill the flask to the mark with demineralized water and mix
thoroughly. Neutralize the contents of the flask and analyze for cyanide.
SUMMARY OF METHOD
The pyridine-pyrazolone method used for measuring cyanide gives an
intense blue color with free cyanide. A sample distillation is required to
determine cyanide from transition and heavy metal cyanide complexes.
REQUIRED REAGENTS
Description
CyaniVer 3 Cyanide Reagent
Powder Pillows . . . . . . . . . 1 pillow . . . 100/pkg . . . . . . . 21068-69
CyaniVer 4 Cyanide Reagent
Powder Pillows . . . . . . . . . 1 pillow . . . 100/pkg . . . . . . . 21069-69
CyaniVer 5 Cyanide Reagent
Powder Pillows . . . . . . . . . 1 pillow . . . 100/pkg . . . . . . . 21070-69
REQUIRED APPARATUS
Clippers, for opening
powder pillows . . . . . . . . . 1 . . . . . . . . . each . . . . . . . . . . . . 968-00
DR/700 Filter Module
Number 61.01. . . . . . . . . . . 1 . . . . . . . . . each . . . . . . . . . . 46261-00
continued
Quantity
Per Test
61-23
Unit Cat. No.