Potentiometric Biosensors Potentiometric electrodes for the analysis of molecules
of biochemical importance can be constructed in a fashion similar to that used for
gas-sensing electrodes. The most common class of potentiometric biosensors are
the so-called enzyme electrodes, in which an enzyme is trapped or immobilized at
the surface of an ion-selective electrode. Reaction of the analyte with the enzyme
produces a product whose concentration is monitored by the ion-selective electrode.
Potentiometric biosensors have also been designed around other biologically
active species, including antibodies, bacterial particles, tissue, and hormone
receptors.
One example of an enzyme electrode is the urea electrode, which is based on
the catalytic hydrolysis of urea by urease