60
ISEs
Ammonium, Nitrate, & Chloride
There are three ion selective electrodes (ISEs) options available for use with the ProSwap Logger:
• Ammonium
• Nitrate
• Chloride
Sensors, Calibration, and Maintenance
4.8
The ammonium and nitrate sensors use a silver/silver chloride
wire electrode in a custom filling solution. The internal
solution is separated from the sample medium by a polymer
membrane, which selectively interacts with ammonium
or nitrate ions. When the sensor is immersed in water, a
potential is established across the membrane that depends
on the relative amounts of ions in the sample and the internal
solution. This potential is read relative to the Ag/AgCl
reference electrode.
The chloride sensor uses a solid-state membrane attached to
a conductive wire. This sensor operates in a similar fashion to
the ammonium and nitrate sensors.
For all ISEs, the linear relationship between the logarithm of
the ammonium, nitrate or chloride activity and the observed
voltage, as predicted by the Nernst equation, is the basis for
the determination.
Guarded
Sensor Tip
Replaceable
Sensor Base