How do we find the existence of charge on colloidal particles? Electrophoresis is theanswer. When an electric field is applied across two electrodes that are totally submerged in a colloidal solution, the particles (colloidal) tend to move towards one or the other electrode. This movement of particles under the effect of electric field is known as electrophoresis.
Ferdinand Frederic Reuss was the first man to observe this phenomenon in 1807. The positively charged particles (cations) that moved towards the cathode were termed as cataphoresis whereas the negatively charged particles (anions) that moved towards anode were termed as anaphoresis.
This technique is carried out in laboratories to carry out DNA and RNA analysis. This technique uses a negative charge to move proteins towards the positive charge.
Let us explain this with the help of an experiment. We use a small test tube with some clear liquid in it and that liquid contains DNA strands of different lengths.
DNA strands can be classified into short, medium and long strands. DNA strands are so small that you can’t even see them under the microscope, but there is a way to find out the DNA strands without touching it or seeing it.
This method is known as Gel electrophoresis. This technique is also helpful in separation of molecules like proteins. Gel is like a sponge and has many holes in it and the gel is used as a filter that sorts the DNA strands. There are small holes present at one end of the gel and we place the DNA samples into these holes. Then with the help of electric current, we make the DNA to move and with the help of electrophoresis process we push the DNA strands through the gel filter.
Long strands move slowly as compared to small strands through the holes in the gel and the strands with same length will move with the same speed. In this way DNA strands sort themselves. To make the strands visible to the naked eye, we stain the sorted group of DNA strands.
This method is used to count the presence of abnormal proteins and absence of normal proteins and also to identify the types of proteins present in high or low amounts in blood. In this process, proteins are divided on the basis of size and electrical charge.
To understand more and dig into the world of many more electrophoresis methods, get yourself enrolled at Byju’s classes.