How are samples prepared for paper chromatography?

In paper chromatography, sample preparation is straightforward and requires only a very small quantity of material. To prepare the sample, the test solution is applied as a small spot near one corner of a sheet of filter paper.12

Before the separation process begins, the paper itself is typically impregnated with a suitable solvent to establish a stationary liquid phase. Once the sample has been spotted onto the paper, an edge of the sheet near the spot is immersed in a second, flowing solvent. As this solvent moves across the paper via capillary action, it carries the components of the sample along with it, separating them based on their varying solubilities in the two solvents.12