Chromatography

Chromatography is used to separate 2 or more dissolved solids in a solution, but these dissolved solids are in very small quantities . Example - Different Dyes from Blank Ink

What is chromatography?

It is a technique used to separate different solutes that dissolve in the same solvent.

This technique is used for separation of different colors .

Example

• It is used to separate different colors of dye.
• It is used to separate drugs from blood
• It is used to separate different colours from pigments

Central Idea behind Chromatography

Different solutes have different solubilities in a solvent. And these solutes are separated using Chromatography

Let's look at a Case where Chromatography is used

Separating Different Colors of Dye

Ink has water as solvent and dye is soluble(solute) in it.

Is DYE  made of Single color?

• No
• Dye in ink is made up of different colors mixed together.

How to Separate Different Colors of Dye

1. Take a small strip of filter paper
2. Draw a line on it (around 3 cm from bottom)
3. Put a small drop of ink at the center of the line using a sketch pen.
4. Let it dry
5. Now take  a beaker filled with some water
6. Lower the filter paper in the beaker
7. Lower end of filter paper should dip in water but ink spot should be just above the water
8. After some times, we see water rise up over the filter paper
9. Different colors of ink are also visible at different heights

Reason :

When water rises up on filter paper, it takes the dye of ink along with it.

• The component which is more soluble in water rises faster and is seen at higher position
• The component which is less soluble is seen below at lower position