How do you set up a chromatography experiment?

To set up a chromatography experiment, you need a stationary phase, a mobile phase, a sample and a chromatography apparatus.

Firstly, you need to understand the two main components of chromatography: the stationary phase and the mobile phase. The stationary phase is a solid or a liquid supported on a solid, while the mobile phase is a liquid or a gas that moves over or through the stationary phase. The stationary phase is usually a piece of chromatography paper or a thin layer of a substance spread on a glass plate. The mobile phase is a suitable solvent or mixture of solvents.

Next, you need to prepare your sample. This could be a mixture of coloured substances, such as food colouring or ink, or a mixture of other substances. The sample is usually dissolved in a suitable solvent to make a solution. The solution is then applied to the stationary phase. This is often done by using a capillary tube to put a small spot of the solution onto the stationary phase.

The stationary phase is then placed in a sealed container with a small amount of the mobile phase. The mobile phase is absorbed into the stationary phase and moves up it. As it does so, it carries the sample with it. Different components of the sample move at different rates, depending on their solubility in the mobile phase and their attraction to the stationary phase. This separates the components of the sample.

The chromatography apparatus is usually a simple set-up. For paper chromatography, for example, you might use a beaker with a lid, a piece of chromatography paper, a pencil to mark the starting line and the positions of the spots, and a suitable solvent. The paper is hung in the beaker so that the bottom of the paper is in the solvent but the spots are above the level of the solvent. The beaker is then sealed and left for a suitable period of time to allow the chromatography to take place.

Remember, safety is paramount when conducting any experiment. Always wear protective clothing, including gloves and goggles, and work in a well-ventilated area.