Download MBBS (Bachelor of Medicine and Bachelor of Surgery) Latest Ion Selective Electrodes Lecture PPT
KEY WORD AND DEFINITIONS
Electrode: A conductor through which an electrical
current enters or leaves a nonmetallic portion of a circuit.
Indicator electrode: Used in potentiometry that produces
a potential representative of the species being measured.
Reference electrode: Is an electrode at which no
appropriate current is allowed to flow and which is used
to observe or control the potential of the indicator or
working electrode, respectively.
Potentiometry: An electrochemical process where the
potential difference is measured between an indicator
electrode and reference electrode when no current is
allowed to flow in the electrochemical cell.
WORKING PRINCIPLE
Membrane potentials are caused by the permeability of
certain types of membranes to selected anions or cations.
Such membranes are used to fabricate ion-selective
electrodes that selectively interact with a single ionic
species.
The potential produced at membrane-sample solution
interface is proportional to the logarithm of the ionic
activity or concentration of the ion in question
Measurements with ISEs are simple, often rapid,
nondestructive, and applicable to a wide range of
concentrations.
The ion-selective membrane is the "heart" of an ISE
as it controls the selectivity of the electrode.
Ion-selective membranes typically consist of glass,
crystalline, polymeric materials.
Ionic-selective electrodes are widely
used clinically for the measurement of
pH, PCO2 and electrolytes in whole
blood, serum, plasma and urine.
This post was last modified on 30 November 2021