Ionode IJ-CN Cyanide User Manual

Page 2

Application

The Ionode IJ-CN Ion selective electrode responds reversibly
to Cyanide, Iodide, Mercuric and Silver ions. The electrode
should not be used in cyanide solutions above 10

-3

M CN.

The electrode only measures cyanide at high pH levels (11-13).
The detection limit is 1 x 10

-6

M CN

Interfering Ions

Max. ratio of Interfering Ions/ Cyanide Ion as follows:

Iodide

1 x10

-2

Bromide

1 x 10

Chloride

1 x 10

Hydroxide

1 x 10

Sulphide

Must be absent

Cleaning

If the membrane is poisoned by interferences the surface
may be renewed by careful polishing with fine wet-and-dry
(P1200 grade). The electrode surface should appear yellow
with a waxy lustre. Always inspect the membrane before use,
and clean if necessary. Organic contaminants can be
removed with ethanol. DO NOT use the electrode in chlorinated
hydrocarbons. Routinely remove the sleeve and replace the
potassium nitrate electrolyte.

Electrolyte Replacement

The electrode has an inbuilt double junction Ag/AgCl with
a replaceable sleeve electrolyte. 1M potassium nitrate is
suitable for most applications. Please consult Ionode Customer
Service if you wish to use a different sleeve electrolyte.

Calibration Standards

Standard solutions of Bromide Ion should preferably bracket
the expected measurement range. For example, to determine
Cyanide ions in the 0.1-10mg/L range, it is usually adequate
to use standard Cyanide solutions in the following values:-
0.1, 1.0, and 10.0 mg/L

The need for ISA (Ionic Strength Adjuster)

It is important to use ISA, so that the Ionic Strength
of standards and samples is independent of the
concentration of the Cyanide Ion.
As a guide, add 25ml 0.1M potassium hydroxide
to every 25ml of calibration standard or sample.
Ensure the pH is at least 11.

Calibration Procedure

With your meter set on mV (or on concentration on
Ion Meters), calibrate by immersing the electrode in
a stirred calibration standard (with added ISA), starting
with the lowest concentration first.
Wait for stability, note the potential in mV, and then
carefully rinse and blot dry the electrode before
repeating with the next highest standard, until all the
calibration standards have been measured.
When using meters that do not have direct
concentration readouts, record the data and graph
the potential against log of the Iodide Ion Concentration.
The graph should have a slope of approximately
-55mV/decade of concentration at 25ºC.

Sample Measurement

Follow the same basic procedures as calibration,
substituting the calibration standard for your sample.
It is important to use the same stirring conditions,
temperature, etc for best results. Use the same ratio
of sample/ISA as used in the calibration step.
Read off the concentration from the graph or directly
from Ion meters.

For more information visit ionode.com

Introduction

This guide contains the basic information for proper use
of your Cyanide Ion selective electrode.

Preparation

IJ series electrodes are shipped without sleeve electrolyte,
and must be filled prior to use. To fill, hold the electrode
by the sleeve and gently ease off the rubber wetting cap.
Prepare as follows:

Fill the annular space with

electrolyte to approximately half
to three quarter full.
1M potassium nitrate is normally
recommended.

Invert the electrode. Hold the

electrode just below the sleeve
and with careful rotation and
pulling along the axis of the
electrode, remove the sleeve.
DO NOT BEND.

Slide the sleeve back onto the electrode ensuring the black

O-ring is well seated within the electrode body. Do not exert
sideways force. Any excess electrolyte will be expelled from the
end of the electrode through the ground junction. Ensure there
are no air bubbles in the sleeve.Wash off any excess electrolyte
before use.

Concentration PPM

GOOD CHEMISTRY