One of the most widely used procedures in the world of chemistry and biology to identify compounds found in a sample is the separation of these components based on prior identification. This prior identification is achieved by studying the velocities at which the components of the mixture or sample move through a porous medium while being entrained by a moving solvent. This process is called chromatography. There are a large number of commercial techniques for doing this, and there are even electronic devices that do it automatically. We will now take a look at how to make a simple chromatography with basic elements.
- A strip of porous paper, which can be filter paper from a coffee machine or an uninked strip of newspaper.
- Markers in different colours.
- A glass tumbler.
- A pen.
The first step is to cut a strip of porous paper 4 cm wide and slightly longer than the length of the glass we are going to use to make the glass. chromatography.
Once we have the porous paper ribbon ready, we are going to fix it to the pen using some adhesive tape. Take care that the free end of the porous paper ribbon goes all the way to the bottom of the glass, while the pen is resting on top of the glass. The appearance is similar to that of any hanging banner or banner, except that it must be inside the glass.
Now, we make a stain with a black felt-tip pen, just at the free end of the porous paper strip about 2cm from the edge. Take care that this stain is intense but not too big, like a sort of thick dot.
It is time to add an amount of alcohol to the glass that is approximately 1 cm high, measured from the bottom of the glass. Now, we place our paper ribbon inside the glass, supporting it with the pen, making sure that the end of the paper is inside the alcohol, but that the black ink stain is located outside the liquid. We can cover the glass to prevent the alcohol from evaporating.
All that remains is to wait and see how the alcohol drags the different components of the ink along the length of the porous paper, observing how stains of different colours appear on the paper, which indicates the variety of inks used to create the black colour. This experiment can be repeated with different coloured inks in order to compare the components of each of them.