Specifications

Gas Sensing – In general, the sensing element of the gas sensing
electrode is made of a Teon® membrane. The gas permeates through the
membrane and changes the pH of the KCl lling solution. The change in
pH is directly proportional to the concentration of ions present.
Glass Bulb – Glass body ion selective electrodes are constructed similar
to a pH electrode since they have a glass bulb that is sensitive to the
species in question.
ISEs are also available in single and double junction constructions. While
the single junction electrodes are suitable for clean water applications,
the double junction electrodes are designed for harsher applications
such as solutions with heavy metals and organic materials.
Calibrating and Ionic Strength Adjuster solutions (ISA) in 480 ml bottles are available.
Contact your nearest distributor for more information.
Electrodes | About ISE Electrodes
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About ISE Electrodes
Introduction to Ion Selective Electrodes (ISE)
The ISE functions in the same principle as the pH electrode. The pH
electrode is the most commonly used ISE that measures the activity of
hydrogen activity in a solution. Ion Selective Electrodes (ISE) respond to
ionic activity or concentration in a liquid because of the characteristics of
the electrode’s sensing membrane. Ideally, the ISE develops an electrical
potential which is proportional to the activity or concentration of the ion
for which the membrane is selective. For example, the uoride electrode
can be used to directly sense uoride ion in drinking water.
Eutech offers a wide selection of ISEs for the measurement of
ammonia, bromide, cadmium, calcium, carbon dioxide, carbonate,
chloride, copper, cyanide, uoride, iodide, lead, nitrate, potassium,
silver, sulde and sodium.
Direct Analysis with Ionic Strength Adjustment
In the direct analysis method, a sample concentration is determined by
measuring the electrode potential and comparing to those obtained
in standard solutions. Normally, an Ionic Strength Adjustor (ISA) and/or
pH adjustor must be added to both the samples and the standards. This
helps in that the closer the standard solution matrix is to the sample
matrix, the more valid is the analysis. A number of standard solutions
are used to standardize a pH/mV/ion meter, or to construct a calibration
curve (by plotting the electrode’s output in mV versus the log of the
concentration). The sample concentration is then read from the meter
or the calibration curve.
The advantages of the direct method of analysis are:
1. Many samples (particularly those with relatively simple ionic
backgrounds) can be quickly measured after a single
calibration procedure
2. The technique is valid over a wide range of concentrations
3. Sample volume values are not required, and may also vary over a
wide range
Calibrating and Ionic Strength Adjuster solutions (ISA) in 480 ml
bottles are available for the various ions measured. Please refer to
the accompanying instruction sheet of each Eutech ISE.
Other methods of measurement that may need the use of ISA are
the known addition, known subtraction, analyte addition and
analyte subtraction methods that are applicable with the colour
touchscreen research-grade CyberScan series 6000 bench meters.
For specic application methods, please refer to the accompanying
instruction manuals of the bench meters.
Types of ISE Constructions
Eutech carries ISEs with the following three types of
sensing elements.
Membrane/Solid State – The solid, polished crystalline membrane of
the solid state ion selective electrode is prepared from either a single or
mixture of compounds. Measurement of the potential is taken across
this membrane.