Lab 3-B Paper Chromatography

Today, we had a lab based on paper chromatography. We dotted food colouring on strips of paper and then dipped them into different test tubes that had water. These dots and the water would slowly travel up the strip of paper. Eventually, the dots and water would stop moving and then we would take out the strips of paper and measure.

1. Measure the distance from the starting line to the solvent front (where the water stopped) (D₂)
2. Measure the distance from the starting line to the middle of where the dot ended up (D₁)
3. 
   

   D₁ ÷D₂
4. This will give you the R_f value for the colour

By finding out the R_f value, we can find out what the mixture (if it is a mixture) is made up of

Example: A green dot will separate into yellow and blue

              Therefore, green is composed of yellow and blue