How does chromatography work?

Many of you might have heard about the word chromatography because it is actually a widely used technique in laboratory but hardly do people know what actually is chromatography.

Ever since forensic science has evolved chromatography has become a very important part of it, specially to detect the various substances which are found on the crime scene and elsewhere.

It is so widely used, that attempts have been made and even succeeded to automate the entire process instead of conducting the tests manually to not only reduce the testing time but also to detect the substances with more precision.

We would be explaining the basic technique of chromatography and how does chromatography work and also its applications in real life in the post below.

Common example of chromatography:

Results of Chromatography experiment on markers of 4 colors.

You might have surely noticed at some point of time or the other that when there are water drops on the paper which consist of ink you might have noticed that instead of just smudging an unusual occurrence might occur which might divide the ink in to areas of different colours and this is the most common example of chromatography at work.

The ink is displaying different colors due to being divided into substances of different properties.

You can also try this yourself by pouring water over a paper which is something written on it with ink.

While chromatography does not occur always in such a case but there are instances when this is very common specially when light is directly cast on the surface.

The reason why ink is divided into different areas of colour is because of the process of chromatography. This is the same principle which is used in chromatography to detect different substances.

Chromatography is mainly used in laboratory to divide mixture is into its ingredients and therefore it is also used in forensic science as well.

What does the word chromatography mean?

Chromatography stands for coloured writing in Greek.

Chromatography basically means the art of separating different ingredients whether they are in the liquid form or the cashier’s form.

The paper ending the example which we gave up or is just the small evidence of the process of chromatography.

How does chromatography work?

In the universe everything is in a state of vibration including yourself and the things besides you but the frequency of vibration is completely different and that means that you are moving at a different speed and the thing which is beside you is moving at a different speed and this fact is what makes chromatography happen because it divides the substances which are moving at different speed.

Simple jist of the process:

If the above explanation was a bit difficult for you to understand then the example which you would be giving below would certainly make it much more simpler for you as to how chromatography works.

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Visualize a race and when you look down upon the starting line with all the runners lined up from a great height it might not be easy to distinguish each and every runner and you can take this is a mixture of substances which you want to separate with the help of chromatography.

When the race actually starts you would find that each runner is moving at a different pace and therefore it actually becomes easier for you to distinguish between the runners and this is what chromatography actually does to the mixture of different substances.

Similarly, when a liquid is actually put on a solid you had to understand that the liquid is moving at a different speed as compared to the solid and with the help of chromatography you can actually see the liquid moving and that is why it appears different from the mixture of solid and liquid in which the liquid was not easily visible earlier.

If you are still finding chromatography difficult to understand then we would actually explain to you about it with the help of another example. Consider a liquid which is actually a mixture of different solutions which is spilled on a surface which is solid.

Now the surface would actually absorb a part of the liquid but not all of it in most of the cases. In most of the cases at the molecule level a process goes on due to which the molecules of the liquid are sucked into the surface for some time period and this is called adsorption but this is not visible to the naked eye and the difference between adsorption and absorption is that in the later the molecules which are sucked into the surface are permanently sucked into the surface whereas in the former there is only exchange of molecules.

The process of chromatography actually uses the former. When these molecules are exchanged with newer molecules of the liquid which is on the surface the molecules which are in the surface take some time to come back to the liquid and this time period is actually different for different types of liquids and this property of the liquid is actually exploited in the process of chromatography to separate one liquid from another or to separate one gets from another.

Different liquid molecules come out from the solid surface at different speeds and therefore that speed at which they move in the solid is an entirely different as well and when you observe this with the help of chromatography it becomes possible to differentiate one liquid from another.

For the process of chromatography to clearly distinguish the liquids or gases we need a large surface material which is solid and if the gap in the molecules of such material is large then the process of chromatography becomes even more evident because the space for the molecules of the liquid or the gas to adsorb in the surface is more and therefore the speed at which they move out of the service is more distinct and therefore the entire process is more evident.

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For practical uses in the industry chromatography can be divided into three types, the first one is paper chromatography, the second one is column chromatography, the third one is gas chromatography.

Paper chromatography:

paper chromatographyThis is the same as the example which we explained above with paper and ink. This experiment might have been carried out by you in school as well. The procedure for this experiment is that you actually drop small quantity of ink on paper and then hang the paper vertically but before that you put alcohol or water near the lower area where you have bought ink.

Then you hang the paper vertically and because of the porous nature of paper the solvent which you have put like alcohol or water actually dissolves the ink and since the paper’s Stationery the ink is actually divided into different components and in some of the cases the different colours might be readily visible but if not then you had to use developing fluids to separate out the different colours from the ink and to help you identify the different constituents of ink.

Column chromatography:

column chromatographyColumn chromatography works on the same principle as paper chromatography but the only difference is that in the column chromatography you actually have a vertical jar filled with a adsorbent liquid like silica gel. Instead of putting ink in the vertical jar the mobile commodity which is to be studied is and used at high pressure in the jar thereby forcing it to exchange the molecules with the crystals which are present in the vertical jar.

The vertical jar resembles the column. One more substances added to the experiment which is eluant which helps the commodity to travel through the crystals. There is one more variation of this method which is known as thin-film chromatography and in this the call which was the vertical jar earlier is replaced with a sheet of glass or metal or plastic but it also contains a thin layer of adsorbent material but in this case these are not crystals but rather a thin layer of liquid adsorbent material.

Gas chromatography:

gas chromatography

Gas chromatography is actually one of the widest used types of chromatography because it is completely automated and therefore the results are much more accurate than the other types of chromatography.

We would explain gas chromatography in steps below:

1.The first step to gas chromatography is the substance which is to be studied and the ingredients are to be found out is actually inserted in a syringe and then it is inserted into the machine which is known as gas chromatography machine. After the substance is heated in the machine it actually vaporises because it is heated at such a level that it cannot sustain its current state and therefore it vaporises.

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2.The chamber in which this vapour is present is injected with a eulant substance which in this case is a gas like hydrogen which is completely neutral. This forms the second step of gas chromatography.

3.This gas actually helps the vapour of the substance to travel through the column which is usually a tube which is made of glass or metal and this tube is actually filled with adsorbent material and in gas chromatography the material which is required should be having a high boiling point so that it does not boil due to the passes of the vapour.

4.After it passes through the adsorbent material the different ingredients of the vapour are differentiated because they pass at different speed through the adsorbent material and at the end of the tube there is a spectrometer which actually analyses these vapours and brings them down in the form of peaks and some other electronic detector can also be used depending on the substance which is to be analysed. The final result is in the form of chromatography that is a chart which in the form of peaks reveals what kind of substances are included and the quantity of those substances as well.

This entire process in gas chromatography is conducted in the gas chromatography machine and therefore it is completely automated and the results are also much more accurate than the other types of chromatography and that is the reason that in the industry gas chromatography is one of the widely used types of chromatography as compared to the other types.

Applications of chromatography:

-Chromatography is widely used in the pharmacy industry to understand about the ingredients of the medicines as well as to vary them depending on the results and the research which they have done.

-Chromatography is also used in forensic science to detect the evidences which they have found and it is widely used to detect the stains of blood as well.

-Chromatography is also used to monitor the presence of poisonous gases and the pollutants in the air. It is also used for detecting water pollution.

-Chromatography is also helpful in detecting chlorophyll in plants which scientists understand the process of photosynthesis.

-Chromatography also helps in understanding the genetically modified food stuffs which are produced these days to ensure that the results are according to the planning.

As you can see chromatography actually has a wide range of applications in almost each and every industry and therefore right from research and development to testing for substances in the forensic industry, it is a wide range of applications.