Narration : 15. Paper Chromatography
- To avoid dirt, place filter paper on another clean paper.
- Lightly draw a circle with a pencil approximately 10 mm radius at the center of a filter paper.
- Draw cross marks on the circle as the starting points of chromatography.
- Cut in the paper to make a solvent-drawing segment.
- Take the sample solution with a capillary, spot the solution lightly on one of the starting points. The spot should be less than 3 mm in diameter. Don't apply a lot of the solution at one time as it will blot.
- You can put the sample and dry the spot with an electric heater a few times to concentrate the sample into a small spot.
- This video shows the behaviors of methyl red and methyl orange individually, and that of a mixture of them in paper chromatography.
- Be careful not to wet the rim and pour the developing solution into a Petri dish.
- Fold the solvent-drawing segment so that it is immersed in the developing solvent.
- Put another Petri dish of the same size on the filter paper as a lid and wait for the development.
- In paper chromatography, the sample moves along with the developing solvent. Separation of the compounds takes place depending on their mobility.
- Here, methyl red moves faster than methyl orange.
- Stop the development just before the front of the developing solvent reaches the edge of the Petri dish.
- Take out the filter paper and immediately mark the front of the developing solvent with a pencil.
- Dry the filter paper with an electric heater.
- Make a mark in the center of the spot.
- Record the shape and color of the spots.
- Measure distance a from the starting point to the mark and distance b from the starting point to the front of the developing solvent. Calculate Rf values by dividing a by b.