Ionode IJ-14 - Manual (Page 2)

Theory in brief
Electrochemical measurements are relative, which raises
the question—what is the correct value?
The standard hydrogen electrode (SHE) has an arbitrarily
assigned value of 0.000V. However, the SHE is impractical to
use, and in most cases either calomel (Hg/Hg
2
Cl
2
/sat KCl) or
Ag/AgCl/sat KCl electrodes are used.
The IJ14 will have a constant potential providing the electrolyte
concentration is kept constant and the secondary sleeve
junction is maintained in a good condition.
Helpful Hints
• Select the correct sleeve electrolyte for the application.
• Keep all connections dry.
• Use a dedicated high impedance pH meter.
• Immerse the electrode so that the reference junction is
below the liquid surface.
• Minimise contact with sulphide vapours and change the
sleeve electrolyte frequently in these conditions.
Maintenance
• When not in use (short term storage), keep the
electrode immersed in 2-3M KCl solution to stabilise
junction potentials.
• Replace sleeve electrolyte when necessary.
The frequency of this is best determined by experience,
however this should be done more often when
measuring contaminated samples.
• For long term storage, remove and clean the sleeve.
Replace the sleeve (without electrolyte) and attach
the wetting cap.
• DO NOT store the electrode in deionized or distilled water.
Cleaning
Cleanliness of the sensor and junction is critical for
accurate measurement as drift is often due to an
unclean sensor/junction. Clean the electrode periodically.
Remove the sleeve and clean the membrane, ground
glass stem and sleeve using one of the following methods.
DO NOT use abrasive materials.
Method One: Alkaline samples and scale: Soak membrane
in 1M HCl for an hour. Wash well with water and
condition in 20% KCl before use.
Method Two: Grease and oil: Wipe the membrane and
ground stem with cotton or tissue soaked in acetone
followed by methylated spirits. Wash with distilled
water before use.
Method Three: Solids and organics: Wipe the membrane
and junction with cotton or tissue soaked in a mild
non-alkaline detergent. Wash with distilled water and
condition in 20% KCl before before use.
This guide contains the basic information for correct use
and maintenance of your new IJ14 reference electrode.
A more comprehensive manual is available for download
from www.ionode.com.au
Preparation
IJ14 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 gel
or electrolyte to approximately
half to three quarter full.
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 side-
ways 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 and store
in 2-3M KCl before use.
3.
Introduction
The IJ14 is a double junction Ag/AgCl reference electrode
suited for use with a wide variety of indicator electrodes
such as pH, ISE and metal half-cells. The double junction
design allows the user to select electrolytes suitable for
use with the majority of ion selective electrode half-cells.
Suitable electrolytes commonly used include KCl, KNO
3
,
NH
4
NO
3
, and ethanolic LiCl. The IJ14 can also be used to
monitor potentials of various processes such as corrosion.
GOOD CHEMISTRY
GOOD CHEMISTRY