Chromatography

• Chromatography separates the components of a mixture in solution. The components of the mixture separate based on the solubility in the solvent and attraction to the paper.
• A pencil line is drawn about one to 2 to centimetres from the bottom of a piece of paper
• A pencil cross is drawn on the pencil line and this is the origin. pencil is used because it will not dissolve
• The paper is then placed in a container with enough solvent in the bottom to reach the bottom of the paper
• The spot that travels the furthest up the paper is the most soluble
• The distance of the solvent moves is marked with a pencil when removed from solvent. This is this solvent front.
• If the substance is to be separated is not coloured, they can be seen under ultraviolet light, or chemical developing agent can be sprayed onto the chromatography to mark the spots by making them coloured
• The distance travelled by the solvent is the mobile
• The paper is the stationary as it does not move
• Rf= distance moved by spot/distance moved by solvent
• Rf value is between 0-1 and can be used to assess purity