Ion-selective Electrode (ISE):
What is Ion selective Electrode?
An ion-selective electrode (ISE), also known as a specific ion electrode (SIE), is a transducer that alters the action of a specific ion dissolved in a solution into an electrical potential. In this article, you will know about the Main equipment used in the measurement of ISE. Besides ISE, the biosensor is used to detect the presence of chemicals in biological samples. However, some of the immunological techniques are used for the detection of infection also.
The main principle of Ion-selective Electrode (ISE):
Ion-selective electrode using liquid membrane: An ideal ion-selective electrode mainly comprised of a thin membrane where only selective ions can be transported. This transport of ions from higher concentration to lower concentration gradient by selective binding creates a potential difference in some sites of membranes.
Main equipment used in ISE measurement:
A pH meter is the type of equipment that is needed for an ISE measurement. Here, I am going to discuss the pH meter:
A pH meter that measures millivolts can also be used to make a bond with an ISE. The pH meter surely has a pin-connector to show the link with the reference electrode. The majority of the ISE’s are mixtures of electrodes that have the reference electrode construct on the body of the ion-selective electrode, but some ion-selective electrodes require a separate reference electrode.
Demonstration with pH meter:
When carrying out selective ion measurements, this is very important to have good demonstration. It offers an unsullied supply of ions to be visible to the portion of ISE. It is very important thing to select a suitable speed that keeps a constant and smooth motion and here rate of turbulent should be avoided.
Adjustment of pH in ISE:
For precise and repeatable measurements the pH control is required in many cases. Some specific ions show different activities when miscellaneous concentrations of hydrogen ions are available in the solution.
Time of response:
For stabilization of the readings, a very long time is required by ISE. While measuring standard solution, at least 15 minutes should be permissible for equilibrium to be established.
Organizing a calibration curve, it is recommended to use about three typical solutions. We use it to know about the estimated values of known solutions while selecting the concentration of typical solutions.
Cleaning with water:
- To assure exact readings, it is necessary to blemish the ion selective electrode between measurements.
- For rinsing purpose, we use deionized water or we can say it as the distilled water. During this process we should not rub the under process electrode by using any material to shake off any excess water.
Conditioning of ISE:
- The ion selective electrode obliged for remaining damp at all times even they are not in use.
- For cleaning, conditioning and storing, we need to check with the manual of an operator.
Safety measures of using ISE (Ion-selective Electrode):
While using ISE, the lab safety rules must be considered. We should take care that ISE should not be stored in water for a long period of time and when you want to store it dry it respectively.
Store joint ISEs in temper solution of ionic strength adjuster.
If we want to store ISEs for a long period of time then get rid of the reference solution of ISA and store it in the dry phase.
Electrodes with a polymer membrane must not have to come in contact with organic solvents.·
Crystal membranes of ISE have to be cleaned with mild abrasive and then rinse with water. For cleaning ISEs, toothpaste is an excellent cleaning agent.