Specifications

Electrodes | About pH Electrodes
Internal Reference Types
| Calomel Reference (Hg/Hg
2
Cl
2
) |
Calomel reference electrodes can give potentials accurate to within 0.01
millivolt. The repeatability and potential stability of such electrodes are
superior to those of the Ag/AgCl electrode, although only at a constant
and relatively low temperature. Calomel is subject to a constant and
relatively low temperature uctuation with a temperature limitation of
80 °C. Calomel is recommended for clinical measurement; for samples
containing protein, tris buers; and for high purity water applications.
| Silver/Silver Chloride Reference (Ag/AgCl) |
Ag/AgCl reference electrodes are largely hysteresis-free and can be used
at a higher temperature with lower temperature coecients. Ag/AgCl
is the best general purpose reference with a wide temperature range
(-5 to 110 °C).
| Double Junction |
A double junction reference is constructed with an Ag/AgCl inner
chamber and a chemically compatible reference solution in the outer
chamber. It is recommended for samples containing organic compounds,
proteins, heavy metals; and other compounds that interact with silver,
such as bromides, iodides, cyanides and suldes.
Rellable Vs Sealed Design
Reference Construction
| Rellable Reference Cell |
Selected for high accuracy, stability, and longer electrode life. Rellable
types sacrice convenience and ease of maintenance.
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Rellable Design
Rell hole allows reference electrolyte
replenishment.
Can be used many times over.
Needs relling when ll solution is low.
Sealed Design
No rell hole. The reference electrolyte
is usually a gel.
Replacement of the electrode is
necessary when it gets contaminated.
Virtually no maintenance is required.
Pour in reference electrolyte
with the relling bottle (that is
supplied with all electrodes)
Twist-close the cap
Twist-open the cap to
expose the relling hole
Patented Twist-Cap Design
Unlike conventional designs which use rubber sleeves, Eutech’s 620
series rellable electrodes feature a patented rell-hole with twist-cap
design – easy-to-use and leak-proof. Relling of reference electrolyte is
hassle-free and quick with no wastage.
| Sealed Reference Cell |
Sealed gel-led reference electrodes are designed for convenience where
minimal maintenance is required. Slightly lower accuracy and shorter life
must be taken into account.