Ionode IJ-Br Bromide - Manual (Page 2)

Application
The Ionode IJ-Br Ion selective electrode responds reversibly
to Bromide and Silver ions. The limit of detection is 5x10
-6 M Br - .
Use known addition for [Br - ] > 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:
Hydroxide
3 x 10 4
Chloride 4 x 10 2
Iodide 2 x 10 -4
Cyanide 8 x 10 -5
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 membrane surface should have 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 IJ-Br 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.
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 Bromide
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 Bromide 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 new Bromide 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.
Bromide ISE. Typical calibration curve
Concentration PPM
225
300
150
75
0.1 1.00 10.00 100.00 1000.00
P
ot
ential mV
Concentration PPM
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