Ionode IJ-I Iodide - Manual (Page 2)

Application
The Ionode IJ-I Ion selective electrode responds reversibly
to Iodide, Cyanide and Silver ions. The limit of detection
is 5 x 10
-8 M Iodide. Use known addition for [I - ] > 0.1M. Try
to avoid exposure of the electrode to direct sunlight, and
avoid use in strong reducing agents.
Interfering Ions
Max. ratio of Interfering Ions/ Bromide Ion as follows
Chloride: 1 x 10
6 , Bromide: 1 x 10 3 , Cyanide: 2 x 10 -2
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 or
yellow-grey with 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 Iodide Ion should preferably bracket
the expected measurement range. For example, to determine
Iodide ions in the 1-40mg/L range, it is usually adequate to
use standard Iodide solutions in the following values:-
1.0, 10.0 and 100.0 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 Iodide
Ion. A suitable ISA is potassium nitrate, which is added to
both standards and samples. As a guide, add 5ml 1M potassium
nitrate to every 25ml of calibration standard or sample.
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 Bromide Ion concentration. The graph should
have a slope of approximately -55mV/decade of
concentration at 25C.
Typical Calibration Curve
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 Iodide 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:
2. Fill the annular space with
electrolyte to approximately half
to three quarter full.
1M potassium nitrate is normally
recommended.
1. 2.
1. 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.
3. 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.
3.
GOOD CHEMISTRY
GOOD CHEMISTRY