How do you prepare a sample for paper chromatography?

To prepare a sample for paper chromatography, you dissolve it in a suitable solvent and apply it to the chromatography paper.

In more detail, the first step in preparing a sample for paper chromatography is to choose a suitable solvent. The solvent, also known as the mobile phase, is the liquid that will carry the sample up the chromatography paper. The choice of solvent depends on the nature of the sample. For example, if the sample is a mixture of coloured substances, you might use water or ethanol as the solvent.

Next, you need to prepare the chromatography paper. This is usually a strip of filter paper. One end of the paper is dipped into the solvent, and the other end is left hanging out of the container. The solvent will gradually rise up the paper by capillary action.

The sample is then applied to the paper. This is done by dissolving the sample in a small amount of the chosen solvent and then using a capillary tube to apply a small spot of the solution onto the paper. The spot should be applied near the bottom of the paper, but not too close to the edge or the solvent. It's important to apply the sample as a small, concentrated spot to ensure that the different components of the mixture can separate effectively.

Once the sample has been applied, the paper is placed in a sealed container with the solvent. The solvent will rise up the paper, carrying the sample with it. As the solvent moves, it will separate the different components of the sample based on their different affinities for the paper and the solvent. This process is known as chromatography.

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