Ionode IJ-Cl Chloride - Manual (Page 2)

Application
The Ionode IJ-Cl Ion selective electrode responds revers-
ibly to Chloride and Silver ions. The limit of detection is 2 x
10-5M Cl
- . Use known addition for [Cl - ] > 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/ chloride ion as follows:
Hydroxide
80
Ammonium 0.1
Thiosulphate 1 x 10 -2
Bromide 3 x 10 -3
Iodide 5 x 10 -7
Cyanide 2 x 10 -7
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 grey or
purple-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 IJ-Cl 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 Chloride Ion should preferably bracket
the expected measurement range.
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 Chloride
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 50ml
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 Chloride Ion
Concentration. The graph should have a slope of
approximately -55mV/decade of concentration at 25C.
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.
Introduction
This guide contains the basic information for proper use
of your Chloride 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.
Chloride ISE. Typical calibration curve
Concentration PPM
250
300
200
150
100
50
0
1 10 100 1000
P
ot
ential mV
Concentration PPM
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