Why we use chromatogtarhy in the method of sepration?

This is a simple method of separating substances, finding its most simple use of separating dyes. We can thus annalyse the substances in it. On the other hand, we can also detect harmful substances from food produced illegally and estimate the level of danger impact on people's health. Hope this helped. And if you need a most specific answer, just ask. Many people may answer and within these, you can perhaps find one that matches your case.

Chromatography is a means of separating molecules out due some component of their physical properties. It involves separating them between two phases a stationary phase and a mobile phase. The greater affinity (attraction) the molecule has to the stationary phase the slower it will move though the material. Therefore molecules can be separated this way.

For example in Thin paper chromatography which is popular for separating dyes at schools, the stationary phase is the paper and the mobile phase is the liquid (usually some sort of alcohol mixture if I remember correctly).

Chromatography is important and useful as the sample can often be recovered in instances such as Ion Exchange Chromatography. This can be useful for purifying substances such as proteins. In the lab this can be very important to have pure protein for other experiments such as X ray crystallography, immunoblotting or NMR. I usually follow this step with a type of liquid chromatography call Gel filtration which separates molecules out due to size exclusion, this results in a protein which is 99% pure - necessary for what I do.

Another type of chromatography which I do to separate proteins is affinity chromatography, my protein has a 'tag' and it bind to a column that I flush it over. I then run buffer over the column which runs off 'elutes' all the non bound substances. How do I get my sample off? I then run another buffer which contains a substance with a higher affinity than by tag and my sample comes off as it is displaced.

It really is a very useful technique and common in lot of labs. I could tell you about all the different types and advantages and disadvantages of each for sample separation but I think I would find it very interesting but you would be bored!

In conclusion chromatography is useful for separating any heterogeneous mixture, provided you choose the right kind.